Asami T

References (45)

Title : New Series of Zaxinone Mimics (MiZax) for Fundamental and Applied Research - Jamil_2023_Biomolecules_13_
Author(s) : Jamil M , Lin PY , Berqdar L , Wang JY , Takahashi I , Ota T , Alhammad N , Chen GE , Asami T , Al-Babili S
Ref : Biomolecules , 13 : , 2023
Abstract : The apocarotenoid zaxinone is a recently discovered regulatory metabolite required for proper rice growth and development. In addition, zaxinone and its two mimics (MiZax3 and MiZax5) were shown to have a remarkable growth-promoting activity on crops and a capability to reduce infestation by the root parasitic plant Striga through decreasing strigolactone (SL) production, suggesting their potential for application in agriculture and horticulture. In the present study, we developed a new series of MiZax via structural modification of the two potent zaxinone mimics (MiZax3 and MiZax5) and evaluated their effect on plant growth and Striga infestation. In general, the structural modifications to MiZax3 and MiZax5 did not additionally improve their overall performance but caused an increase in certain activities. In conclusion, MiZax5 and especially MiZax3 remain the likely most efficient zaxinone mimics for controlling Striga infestation.
ESTHER : Jamil_2023_Biomolecules_13_
PubMedSearch : Jamil_2023_Biomolecules_13_
PubMedID: 37627271

Title : Zaxinone mimics (MiZax) efficiently promote growth and production of potato and strawberry plants under desert climate conditions - Wang_2023_Sci.Rep_13_17438
Author(s) : Wang JY , Jamil M , AlOtaibi TS , Abdelaziz ME , Ota T , Ibrahim OH , Berqdar L , Asami T , Ahmed Mousa MA , Al-Babili S
Ref : Sci Rep , 13 :17438 , 2023
Abstract : Climate changes and the rapid expanding human population have become critical concerns for global food security. One of the promising solutions is the employment of plant growth regulators (PGRs) for increasing crop yield and overcoming adverse growth conditions, such as desert climate. Recently, the apocarotenoid zaxinone and its two mimics (MiZax3 and MiZax5) have shown a promising growth-promoting activity in cereals and vegetable crops under greenhouse and field conditions. Herein, we further investigated the effect of MiZax3 and MiZax5, at different concentrations (5 and 10 microM in 2021; 2.5 and 5 microM in 2022), on the growth and yield of the two valuable vegetable crops, potato and strawberry, in the Kingdom of Saudi of Arabia. Application of both MiZax significantly increased plant agronomic traits, yield components and total yield, in five independent field trials from 2021 to 2022. Remarkably, the amount of applied MiZax was far less than humic acid, a widely applied commercial compound used here for comparison. Hence, our results indicate that MiZax are very promising PGRs that can be applied to promote the growth and yield of vegetable crops even under desert conditions and at relatively low concentrations.
ESTHER : Wang_2023_Sci.Rep_13_17438
PubMedSearch : Wang_2023_Sci.Rep_13_17438
PubMedID: 37838798

Title : Synthesis of Carlactone Derivatives to Develop a Novel Inhibitor of Strigolactone Biosynthesis - Kawada_2023_ACS.Omega_8_13855
Author(s) : Kawada K , Saito T , Onoda S , Inayama T , Takahashi I , Seto Y , Nomura T , Sasaki Y , Asami T , Yajima S , Ito S
Ref : ACS Omega , 8 :13855 , 2023
Abstract : Strigolactones (SLs), phytohormones that inhibit shoot branching in plants, promote the germination of root-parasitic plants, such as Striga spp. and Orobanche spp., which drastically reduces the crop yield. Therefore, reducing SL production via chemical treatment may increase the crop yield. To design specific inhibitors, it is valid to utilize the substrate structure of the target proteins as lead compounds. In this study, we focused on Os900, a rice enzyme that oxidizes the SL precursor carlactone (CL) to 4-deoxyorobanchol (4DO), and synthesized 10 CL derivatives. The effects of the synthesized CL derivatives on SL biosynthesis were evaluated by the Os900 enzyme assay in vitro and by measuring 4DO levels in rice root exudates. We identified some CL derivatives that inhibited SL biosynthesis in vitro and in vivo.
ESTHER : Kawada_2023_ACS.Omega_8_13855
PubMedSearch : Kawada_2023_ACS.Omega_8_13855
PubMedID: 37091382

Title : Rational design of Striga hermonthica-specific seed germination inhibitors - Zarban_2022_Plant.Physiol_188_1369
Author(s) : Zarban RA , Hameed UFS , Jamil M , Ota T , Wang JY , Arold ST , Asami T , Al-Babili S
Ref : Plant Physiol , 188 :1369 , 2022
Abstract : The obligate hemiparasitic weed Striga hermonthica grows on cereal roots and presents a severe threat to global food security by causing enormous yield losses, particularly in sub-Saharan Africa. The rapidly increasing Striga seed bank in infested soils provides a major obstacle in controlling this weed. Striga seeds require host-derived strigolactones (SLs) for germination, and corresponding antagonists could be used as germination inhibitors. Recently, we demonstrated that the common detergent Triton X-100 is a specific inhibitor of Striga seed germination by binding noncovalently to its receptor, S. hermonthica HYPO-SENSITIVE TO LIGHT 7 (ShHTL7), without blocking the rice (Oryza sativa) SL receptor DWARF14 (OsD14). Moreover, triazole ureas, the potent covalently binding antagonists of rice SL perception with much higher activity toward OsD14, showed inhibition of Striga but were less specific. Considering that Triton X-100 is not suitable for field application and by combining structural elements of Triton and triazole urea, we developed two hybrid compounds, KK023-N1 and KK023-N2, as potential Striga-specific germination inhibitors. Both compounds blocked the hydrolysis activity of ShHTL7 but did not affect that of OsD14. Binding of KK023-N1 diminished ShHTL7 interaction with S. hermonthica MORE AXILLARY BRANCHING 2, a major component in SL signal transduction, and increased ShHTL7 thermal specificity. Docking studies indicate that KK023-N1 binding is not covalent but is caused by hydrophobic interactions. Finally, in vitro and greenhouse tests revealed specific inhibition of Striga seed germination, which led to a 38% reduction in Striga infestation in pot experiments. These findings reveal that KK023-N1 is a potential candidate for combating Striga and a promising basis for rational design and development of further Striga-specific herbicides.
ESTHER : Zarban_2022_Plant.Physiol_188_1369
PubMedSearch : Zarban_2022_Plant.Physiol_188_1369
PubMedID: 34850204
Gene_locus related to this paper: strhe-ShHTL7

Title : Striga hermonthica Suicidal Germination Activity of Potent Strigolactone Analogs: Evaluation from Laboratory Bioassays to Field Trials - Jamil_2022_Plants.(Basel)_11__
Author(s) : Jamil M , Wang JY , Yonli D , Ota T , Berqdar L , Traore H , Margueritte O , Zwanenburg B , Asami T , Al-Babili S
Ref : Plants (Basel) , 11 : , 2022
Abstract : The obligate hemiparasite Striga hermonthica is one of the major global biotic threats to agriculture in sub-Saharan Africa, causing severe yield losses of cereals. The germination of Striga seeds relies on host-released signaling molecules, mainly strigolactones (SLs). This dependency opens up the possibility of deploying SL analogs as "suicidal germination agents" to reduce the accumulated seed bank of Striga in infested soils. Although several synthetic SL analogs have been developed for this purpose, the utility of these compounds in realizing the suicidal germination strategy for combating Striga is still largely unknown. Here, we evaluated the efficacy of three potent SL analogs (MP3, MP16, and Nijmegen-1) under laboratory, greenhouse, and farmer's field conditions. All investigated analogs showed around a 50% Striga germination rate, equivalent to a 50% reduction in infestation, which was comparable to the standard SL analog GR24. Importantly, MP16 had the maximum reduction of Striga emergence (97%) in the greenhouse experiment, while Nijmegen-1 appeared to be a promising candidate under field conditions, with a 43% and 60% reduction of Striga emergence in pearl millet and sorghum fields, respectively. These findings confirm that the selected SL analogs appear to make promising candidates as simple suicidal agents both under laboratory and real African field conditions, which may support us to improve suicidal germination technology to deplete the Striga seed bank in African agriculture.
ESTHER : Jamil_2022_Plants.(Basel)_11__
PubMedSearch : Jamil_2022_Plants.(Basel)_11__
PubMedID: 35448773

Title : Function of hydroxycinnamoyl spermidines in seedling growth of Arabidopsis - Takahashi_2022_Biosci.Biotechnol.Biochem_86_294
Author(s) : Takahashi I , Ota T , Asami T
Ref : Biosci Biotechnol Biochem , 86 :294 , 2022
Abstract : Hydroxycinnamic acid amides are involved in various developmental processes as well as in biotic and abiotic stress responses. Among them, the presence of spermidine derivatives, such as N1,N8-di(coumaroyl)-spermidine and N1,N8-di(sinapoyl)-spermidine, and their biosynthetic genes have been reported in Arabidopsis, but their functions in plants are still unknown. We chemically synthesized the above-mentioned spermidine derivatives to assess their physiological functions in Arabidopsis. We evaluated the growth and development of chemically treated Arabidopsis and demonstrated that these compounds inhibited seed germination, hypocotyl elongation, and primary root growth, which could be due to modulation of plant hormone homeostasis and signaling. The results suggest that these compounds are regulatory metabolites that modulate plant growth and development.
ESTHER : Takahashi_2022_Biosci.Biotechnol.Biochem_86_294
PubMedSearch : Takahashi_2022_Biosci.Biotechnol.Biochem_86_294
PubMedID: 34958361

Title : Canonical strigolactones are not the major determinant of tillering but important rhizospheric signals in rice - Ito_2022_Sci.Adv_8_eadd1278
Author(s) : Ito S , Braguy J , Wang JY , Yoda A , Fiorilli V , Takahashi I , Jamil M , Felemban A , Miyazaki S , Mazzarella T , Chen GE , Shinozawa A , Balakrishna A , Berqdar L , Rajan C , Ali S , Haider I , Sasaki Y , Yajima S , Akiyama K , Lanfranco L , Zurbriggen MD , Nomura T , Asami T , Al-Babili S
Ref : Sci Adv , 8 :eadd1278 , 2022
Abstract : Strigolactones (SLs) are a plant hormone inhibiting shoot branching/tillering and a rhizospheric, chemical signal that triggers seed germination of the noxious root parasitic plant Striga and mediates symbiosis with beneficial arbuscular mycorrhizal fungi. Identifying specific roles of canonical and noncanonical SLs, the two SL subfamilies, is important for developing Striga-resistant cereals and for engineering plant architecture. Here, we report that rice mutants lacking canonical SLs do not show the shoot phenotypes known for SL-deficient plants, exhibiting only a delay in establishing arbuscular mycorrhizal symbiosis, but release exudates with a significantly decreased Striga seed-germinating activity. Blocking the biosynthesis of canonical SLs by TIS108, a specific enzyme inhibitor, significantly lowered Striga infestation without affecting rice growth. These results indicate that canonical SLs are not the determinant of shoot architecture and pave the way for increasing crop resistance by gene editing or chemical treatment.
ESTHER : Ito_2022_Sci.Adv_8_eadd1278
PubMedSearch : Ito_2022_Sci.Adv_8_eadd1278
PubMedID: 36322663

Title : Evaluation of the Biostimulant Activity of Zaxinone Mimics (MiZax) in Crop Plants - Wang_2022_Front.Plant.Sci_13_874858
Author(s) : Wang JY , Jamil M , Hossain MG , Chen GE , Berqdar L , Ota T , Blilou I , Asami T , Al-Solimani SJ , Mousa MAA , Al-Babili S
Ref : Front Plant Sci , 13 :874858 , 2022
Abstract : Global food security is a critical concern that needs practical solutions to feed the expanding human population. A promising approach is the employment of biostimulants to increase crop production. Biostimulants include compounds that boost plant growth. Recently, mimics of zaxinone (MiZax) were shown to have a promising growth-promoting effect in rice (Oryza sativa). In this study, we investigated the effect of MiZax on the growth and yield of three dicot horticultural plants, namely, tomato (Solanum lycopersicum), capsicum (Capsicum annuum), and squash (Cucurbita pepo) in different growth environments, as well as on the growth and development of the monocot date palm (Phoenix dactylifera), an important crop in the Middle East. The application of MiZax significantly enhanced plant height, flower, and branch numbers, fruit size, and total fruit yield in independent field trials from 2020 to 2021. Importantly, the amount of applied MiZax was far less than that used with the commercial compound humic acid, a widely used biostimulant in horticulture. Our results indicate that MiZax have significant application potential to improve the performance and productivity of horticultural crops.
ESTHER : Wang_2022_Front.Plant.Sci_13_874858
PubMedSearch : Wang_2022_Front.Plant.Sci_13_874858
PubMedID: 35783933

Title : Chemical Synthesis of Triazole-Derived Suppressors of Strigolactone Functions - Ito_2021_Methods.Mol.Biol_2309_25
Author(s) : Ito S , Kikuzato K , Nakamura H , Asami T
Ref : Methods Mol Biol , 2309 :25 , 2021
Abstract : Triazole is a five-membered heteroring consists of two carbon atoms and three nitrogen atoms and exhibits a wide range of biological activities. The basic heterocyclic rings are 1,2,3-triazole and 1,2,4-triazole. Here we describe the chemical synthetic methods for triazole derivatives that can suppress the function of SL by inhibiting SL biosynthesis pathway or SL perception sites such as D14.
ESTHER : Ito_2021_Methods.Mol.Biol_2309_25
PubMedSearch : Ito_2021_Methods.Mol.Biol_2309_25
PubMedID: 34028676

Title : Strigolactone signaling inhibition increases adventitious shoot formation on internodal segments of ipecac - Okazaki_2021_Planta_253_123
Author(s) : Okazaki K , Watanabe S , Koike I , Kawada K , Ito S , Nakamura H , Asami T , Shimomura K , Umehara M
Ref : Planta , 253 :123 , 2021
Abstract : SL inhibited adventitious shoot formation of ipecac, whereas the SL-related inhibitors promoted adventitious shoot formation. SL-related inhibitors might be useful as new plant growth regulators for plant propagation. In most plant species, phytohormones are required to induce adventitious shoots for propagating economically important crops and regenerating transgenic plants. In ipecac (Carapichea ipecacuanha (Brot.) L. Andersson), however, adventitious shoots can be formed without phytohormone treatment. Here we evaluated the effects of GR24 (a synthetic strigolactone, SL), SL biosynthetic inhibitors, and an SL antagonist on adventitious shoot formation during tissue culture of ipecac. We found that exogenously applied GR24 suppressed indole-3-acetic acid transport in internodal segments and decreased the number of adventitious shoots formed; in addition, the distribution of adventitious shoots changed from the apical to middle region of the internodal segments. In contrast, the SL-related inhibitors promoted adventitious shoot formation on both apical and middle regions of the segments. In particular, SL antagonist treatment increased endogenous cytokinin levels and induced multiple shoot development. These results indicate that SL inhibits adventitious shoot formation in ipecac. In ipecac, one of the shoots in each internodal segment becomes dominant and auxin derived from that shoot suppresses the other shoot growth. Here, this dominance was overcome by application of SL-related inhibitors. Therefore, SL-related inhibitors might be useful as new plant growth regulators to improve the efficiency of plant propagation in vitro.
ESTHER : Okazaki_2021_Planta_253_123
PubMedSearch : Okazaki_2021_Planta_253_123
PubMedID: 34014387

Title : On improving strigolactone mimics for induction of suicidal germination of the root parasitic plant Striga hermonthica - Takahashi_2021_aBIOTECH_2_1
Author(s) : Takahashi I , Fukui K , Asami T
Ref : aBIOTECH , 2 :1 , 2021
Abstract : Strigolactones (SLs) are plant hormones that regulate the branching of plants and seed germination stimulants of root parasitic plants. As root parasites are a great threat to agricultural production, the use of SL agonists could be anticipated to provide an efficient method for regulating root parasites as suicidal germination inducers. A series of phenoxyfuranone-type SL mimics, termed debranones, has been reported to show potent bioactivities, including reduction of the tiller number on rice, and stimulation of seed germination in the root parasite Striga hermonthica. To exert both activities, two substituents on the phenyl ring of the molecules were important but at least a substituent at the 2-position must be an electron-withdrawing group. However, little is known about the effect of the properties of the substituents at the 2-position on bioactivities. Here, we found that different substituents at the 2-position give different preferences for bioactivities. Halogenated debranones were more effective than the others and SL agonist GR24 for inhibiting rice tiller but far less effective in the induction of S. hermonthica germination. Meanwhile, nitrile and methyl derivatives clearly stimulated the germination of S. hermonthica seeds. Although their IC50 values were 100 times higher than that of GR24 in the receptor competitive binding assay, their physiological activities were approximately 1/10 of GR24. These differences could be due to their uptake in plants and/or their physicochemical stability under our experimental conditions. These findings could support the design of more potent and selective SL agonists that could contribute to solving big agricultural issues.
ESTHER : Takahashi_2021_aBIOTECH_2_1
PubMedSearch : Takahashi_2021_aBIOTECH_2_1

Title : A New Series of Carlactonoic Acid Based Strigolactone Analogs for Fundamental and Applied Research - Jamil_2020_Front.Plant.Sci_11_434
Author(s) : Jamil M , Kountche BA , Wang JY , Haider I , Jia KP , Takahashi I , Ota T , Asami T , Al-Babili S
Ref : Front Plant Sci , 11 :434 , 2020
Abstract : Strigolactones (SLs) are a group of carotenoid derived plant hormones that play a key role in establishing plant architecture and adapting it to environmental changes, and are involved in plants response to biotic and abiotic stress. SLs are also released into the soil to serve as a chemical signal attracting beneficial mycorrhizal fungi. However, this signal also induces seed germination in root parasitic weeds that represent a major global threat for agriculture. This wide spectrum of biological functions has made SL research one of the most important current topics in fundamental and applied plant science. The availability of SLs is crucial for investigating SL biology as well as for agricultural application. However, natural SLs are produced in very low amounts, and their organic synthesis is quite difficult, which creates a need for efficient and easy-to-synthesize analogs and mimics. Recently, we have generated a set of SL analogs, Methyl Phenlactonoates (MPs), which resemble the non-canonical SL carlactonoic acid. In this paper, we describe the development and characterization of a new series of easy-to-synthesize MPs. The new analogs were assessed with respect to regulation of shoot branching, impact on leaf senescence, and induction of seed germination in different root parasitic plants species. Some of the new analogs showed higher efficiency in inhibiting shoot branching as well as in triggering parasitic seed germination, compared to the commonly used GR24. MP16 was the most outstanding analog showing high activity in different SL biological functions. In summary, our new analogs series contains very promising candidates for different applications, which include the usage in studies for understanding different aspects of SL biology as well as large scale field application for combating root parasitic weeds, such as Striga hermonthica that devastates cereal yields in sub-Saharan Africa.
ESTHER : Jamil_2020_Front.Plant.Sci_11_434
PubMedSearch : Jamil_2020_Front.Plant.Sci_11_434
PubMedID: 32373143

Title : Efficient Mimics for Elucidating Zaxinone Biology and Promoting Agricultural Applications - Wang_2020_Mol.Plant_13_1654
Author(s) : Wang JY , Jamil M , Lin PY , Ota T , Fiorilli V , Novero M , Zarban RA , Kountche BA , Takahashi I , Martinez C , Lanfranco L , Bonfante P , de Lera AR , Asami T , Al-Babili S
Ref : Mol Plant , 13 :1654 , 2020
Abstract : Zaxinone is an apocarotenoid regulatory metabolite required for normal rice growth and development. In addition, zaxinone has a large application potential in agriculture, due to its growth-promoting activity and capability to alleviate infestation by the root parasitic plant Striga through decreasing strigolactone (SL) production. However, zaxinone is poorly accessible to the scientific community because of its laborious organic synthesis that impedes its further investigation and utilization. In this study, we developed easy-to-synthesize and highly efficient mimics of zaxinone (MiZax). We performed a structure-activity relationship study using a series of apocarotenoids distinguished from zaxinone by different structural features. Using the obtained results, we designed several phenyl-based compounds synthesized with a high-yield through a simple method. Activity tests showed that MiZax3 and MiZax5 exert zaxinone activity in rescuing root growth of a zaxinone-deficient rice mutant, promoting growth, and reducing SL content in roots and root exudates of wild-type plants. Moreover, these compounds were at least as efficient as zaxinone in suppressing transcript level of SL biosynthesis genes and in alleviating Striga infestation under greenhouse conditions, and did not negatively impact mycorrhization. Taken together, MiZax are a promising tool for elucidating zaxinone biology and investigating rice development, and suitable candidates for combating Striga and increasing crop growth.
ESTHER : Wang_2020_Mol.Plant_13_1654
PubMedSearch : Wang_2020_Mol.Plant_13_1654
PubMedID: 32835886

Title : Methylation at the C-3' in D-Ring of Strigolactone Analogs Reduces Biological Activity in Root Parasitic Plants and Rice - Jamil_2019_Front.Plant.Sci_10_353
Author(s) : Jamil M , Kountche BA , Haider I , Wang JY , Aldossary F , Zarban RA , Jia KP , Yonli D , Shahul Hameed UF , Takahashi I , Ota T , Arold ST , Asami T , Al-Babili S
Ref : Front Plant Sci , 10 :353 , 2019
Abstract : Strigolactones (SLs) regulate plant development and induce seed germination in obligate root parasitic weeds, e.g. Striga spp. Because organic synthesis of natural SLs is laborious, there is a large need for easy-to-synthesize and efficient analogs. Here, we investigated the effect of a structural modification of the D-ring, a conserved structural element in SLs. We synthesized and investigated the activity of two analogs, MP13 and MP26, which differ from previously published AR8 and AR36 only in the absence of methylation at C-3'. The de-methylated MP13 and MP26 were much more efficient in regulating plant development and inducing Striga seed germination, compared with AR8. Hydrolysis assays performed with purified Striga SL receptor and docking of AR8 and MP13 to the corresponding active site confirmed and explained the higher activity. Field trials performed in a naturally Striga-infested African farmer's field unraveled MP13 as a promising candidate for combating Striga by inducing germination in host's absence. Our findings demonstrate that methylation of the C-3' in D-ring in SL analogs has a negative impact on their activity and identify MP13 and, particularly, MP26 as potent SL analogs with simple structures, which can be employed to control Striga, a major threat to global food security.
ESTHER : Jamil_2019_Front.Plant.Sci_10_353
PubMedSearch : Jamil_2019_Front.Plant.Sci_10_353
PubMedID: 31001294

Title : Triazole Ureas Covalently Bind to Strigolactone Receptor and Antagonize Strigolactone Responses - Nakamura_2019_Mol.Plant_12_44
Author(s) : Nakamura H , Hirabayashi K , Miyakawa T , Kikuzato K , Hu W , Xu Y , Jiang K , Takahashi I , Niiyama R , Dohmae N , Tanokura M , Asami T
Ref : Mol Plant , 12 :44 , 2019
Abstract : Strigolactones, a class of plant hormones with multiple functions, mediate plant-plant and plant-microorganism communications in the rhizosphere. In this study, we developed potent strigolactone antagonists, which covalently bind to the strigolactone receptor D14, by preparing an array of triazole urea compounds. Using yeast two-hybrid and rice-tillering assays, we identified a triazole urea compound KK094 as a potent inhibitor of strigolactone receptors. Liquid chromatography-tandem mass spectrometry analysis and X-ray crystallography revealed that KK094 was hydrolyzed by D14, and that a reaction product of this degradation covalently binds to the Ser residue of the catalytic triad of D14. Furthermore, we identified two triazole urea compounds KK052 and KK073, whose effects on D14-D53/D14-SLR1 complex formation were opposite due to the absence (KK052) or presence (KK073) of a trifluoromethyl group on their phenyl ring. These results demonstrate that triazole urea compounds are potentially powerful tools for agricultural application and may be useful for the elucidation of the complicated mechanism underlying strigolactone perception.
ESTHER : Nakamura_2019_Mol.Plant_12_44
PubMedSearch : Nakamura_2019_Mol.Plant_12_44
PubMedID: 30391752
Gene_locus related to this paper: orysj-Q10QA5

Title : Synthetic agonist of HTL\/KAI2 shows potent stimulating activity for Arabidopsis seed germination - Fukui_2019_Bioorg.Med.Chem.Lett_29_2487
Author(s) : Fukui K , Arai K , Kasahara H , Asami T , Hayashi KI
Ref : Bioorganic & Medicinal Chemistry Lett , 29 :2487 , 2019
Abstract : HTL/KAI2, a member of the alpha/beta-fold hydrolase superfamily, is known to be a receptor-like protein of lactone compounds and that triggers seed germination of Arabidopsis. However, the endogenous ligand and physiological roles of HTL/KAI2 have remained unclear. To understand the mechanism underlying seed germination involved in HTL/KAI2 signaling, it is necessary to identify the endogenous ligand of HTL/KAI2. To date, even a biosynthetic mutant of the ligand has not yet been isolated. Because exogenous agonistic chemicals can only be purchased in small amounts at high prices, the limited supply of those chemicals has hampered any large-scale experiments, such as mutant screening. Therefore, easily synthesized and scalable artificial agonist would remove the limitation of the chemical supply and contribute to the identification of the endogenous ligand of HTL/KAI2 and/or the biosynthetic mutants. In this study, we demonstrated that designed chemicals with a phenoxyfuranone scaffold potently stimulated seed germination via HTL/KAI2 in Arabidopsis. As a result of screening of these chemicals, we selected a representative compound with convincing selectivity. Here in, we provide a new promising synthetic agonist of HTL/KAI2.
ESTHER : Fukui_2019_Bioorg.Med.Chem.Lett_29_2487
PubMedSearch : Fukui_2019_Bioorg.Med.Chem.Lett_29_2487
PubMedID: 31345632
Gene_locus related to this paper: arath-KAI2.D14L

Title : Synthesis and Biological Evaluation of Novel Triazole Derivatives as Strigolactone Biosynthesis Inhibitors - Kawada_2019_J.Agric.Food.Chem_67_6143
Author(s) : Kawada K , Takahashi I , Arai M , Sasaki Y , Asami T , Yajima S , Ito S
Ref : Journal of Agricultural and Food Chemistry , 67 :6143 , 2019
Abstract : Strigolactones (SLs) are one of the plant hormones that control several important agronomic traits, such as shoot branching, leaf senescence, and stress tolerance. Manipulation of the SL biosynthesis can increase the crop yield. We previously reported that a triazole derivative, TIS108, inhibits SL biosynthesis. In this study, we synthesized a number of novel TIS108 derivatives. Structure-activity relationship studies revealed that 4-(2-phenoxyethoxy)-1-phenyl-2-(1 H-1,2,4-triazol-1-yl)butan-1-one (KK5) inhibits the level of 4-deoxyorobanchol in roots more strongly than TIS108. We further found that KK5-treated Arabidopsis showed increased branching phenotype with the upregulated gene expression of AtMAX3 and AtMAX4. These results indicate that KK5 is a specific SL biosynthesis inhibitor in rice and Arabidopsis.
ESTHER : Kawada_2019_J.Agric.Food.Chem_67_6143
PubMedSearch : Kawada_2019_J.Agric.Food.Chem_67_6143
PubMedID: 31083983

Title : Regulation of biosynthesis, perception, and functions of strigolactones for promoting arbuscular mycorrhizal symbiosis and managing root parasitic weeds - Yoneyama_2019_Pest.Manag.Sci_75_2353
Author(s) : Yoneyama K , Xie X , Nomura T , Takahashi I , Asami T , Mori N , Akiyama K , Kusajima M , Nakashita H
Ref : Pest Manag Sci , 75 :2353 , 2019
Abstract : Strigolactones (SLs) are carotenoid-derived plant secondary metabolites that play important roles in various aspects of plant growth and development as plant hormones, and in rhizosphere communications with symbiotic microbes and also root parasitic weeds. Therefore, sophisticated regulation of the biosynthesis, perception and functions of SLs is expected to promote symbiosis of beneficial microbes including arbuscular mycorrhizal (AM) fungi and also to retard parasitism by devastating root parasitic weeds. We have developed SL mimics with different skeletons, SL biosynthesis inhibitors acting at different biosynthetic steps, SL perception inhibitors that covalently bind to the SL receptor D14, and SL function inhibitors that bind to the serine residue at the catalytic site. In greenhouse pot tests, TIS108, an azole-type SL biosynthesis inhibitor effectively reduced numbers of attached root parasites Orobanche minor and Striga hermonthica without affecting their host plants; tomato and rice, respectively. AM colonization resulted in weak but distinctly enhanced plant resistance to pathogens. SL mimics can be used to promote AM symbiosis and to reduce the application rate of systemic-acquired resistance inducers which are generally phytotoxic to horticultural crops. (c) 2019 Society of Chemical Industry.
ESTHER : Yoneyama_2019_Pest.Manag.Sci_75_2353
PubMedSearch : Yoneyama_2019_Pest.Manag.Sci_75_2353
PubMedID: 30843315

Title : Strigolactones-a novel class of phytohormones as anti-cancer agents - Hasan_2018_J.Pestic.Sci_43_168
Author(s) : Hasan MN , Razvi SSI , Kuerban A , Balamash KS , Al-Bishri WM , Abulnaja KO , Choudhry H , Khan JA , Moselhy SS , M Z , Kumosani TA , Al-Malki AL , Alhosin M , Asami T
Ref : J Pestic Sci , 43 :168 , 2018
Abstract : Chemotherapy shows some promising results in the inhibition of cancer, but resistance to chemotherapy and its severe side effects may occur in due course, resulting in only restricted and narrow benefits. Therefore, there is a pressing need to find alternative chemotherapeutic drugs for combating cancers. Plants have been used since ages in medicine, and by the dawn of 19th century, various potent and promising anti-cancer products have been derived from plants. Strigolactones (SLs) are a novel class of phytohormones involved in regulating the branching of shoots. Recently, many novel synthesized SL analogues have been found to be effective against solid and non-solid tumours. These hormones have been reported to have a unique mechanism of inhibiting cancer cells by lowering their viability and promoting apoptosis and cell death at micromolar concentrations. Therefore, synthetic SL analogues could be future potent anti-cancer drug candidates. Further research is needed to identify and deduce the significance of these synthetic SL analogues.
ESTHER : Hasan_2018_J.Pestic.Sci_43_168
PubMedSearch : Hasan_2018_J.Pestic.Sci_43_168
PubMedID: 30363122

Title : Effects of gibberellin and strigolactone on rice tiller bud growth - Ito_2018_J.Pestic.Sci_43_220
Author(s) : Ito S , Yamagami D , Asami T
Ref : J Pestic Sci , 43 :220 , 2018
Abstract : Strigolactones (SLs) regulate diverse developmental phenomena. Rice SL biosynthesis and signaling mutants have an increased number of tillers and a reduced plant height relative to wild-type (WT) rice plants. In this study, we tested the effectiveness of gibberellin (GA) on restoring more tillering phenotype and dwarfism observed in both SL biosynthesis and signaling mutants. The application of GA to these mutants rescued the tiller bud outgrowth; however, the sensitivity to GA was different between the WT and the SL biosynthesis mutant.
ESTHER : Ito_2018_J.Pestic.Sci_43_220
PubMedSearch : Ito_2018_J.Pestic.Sci_43_220
PubMedID: 30363138

Title : Structural analysis of HTL and D14 proteins reveals the basis for ligand selectivity in Striga - Xu_2018_Nat.Commun_9_3947
Author(s) : Xu Y , Miyakawa T , Nosaki S , Nakamura A , Lyu Y , Nakamura H , Ohto U , Ishida H , Shimizu T , Asami T , Tanokura M
Ref : Nat Commun , 9 :3947 , 2018
Abstract : HYPOSENSITIVE TO LIGHT (HTL) and DWARF14 (D14) mediate the perception of karrikin and strigolactone, which stimulates germination of the parasitic weed Striga. However, their role in parasitic seeds is poorly understood, and the basis for their differing responsiveness remains unclear. Here, we show that Striga hermonthica HTL proteins (ShHTLs) in 'conserved' and 'intermediate' clades are able to bind karrikin. The 'divergent' clade is able to hydrolyze strigolactone. Unexpectedly, we find that ShD14 is also capable of hydrolyzing strigolactone. Through comparative analysis of ShHTLs and ShD14 crystal structures, we provide insights into the basis for their selectivity. Moreover, we show that both ShD14 and divergent clade ShHTLs, but not conserved and intermediate clade ShHTLs, can interact with the putative downstream signaling component ShMAX2 in the presence of the synthetic strigolactone, rac-GR24. These findings provide insight into how strigolactone is perceived and how ligand specificity is determined.
ESTHER : Xu_2018_Nat.Commun_9_3947
PubMedSearch : Xu_2018_Nat.Commun_9_3947
PubMedID: 30258184
Gene_locus related to this paper: strhe-ShD14 , strhe-ShHTL4 , strhe-ShHTL1 , strhe-ShHTL7

Title : Plant Chemical Biology -
Author(s) : Kinoshita T , McCourt P , Asami T , Torii KU
Ref : Plant Cell Physiol , 59 :1483 , 2018
PubMedID: 30032233

Title : Characterization of a helminthosporic acid analog that is a selective agonist of gibberellin receptor - Miyazaki_2018_Bioorg.Med.Chem.Lett_28_2465
Author(s) : Miyazaki S , Tomita K , Yamane H , Kobayashi M , Asami T , Nakajima M
Ref : Bioorganic & Medicinal Chemistry Lett , 28 :2465 , 2018
Abstract : Helminthosporol, a natural growth regulator isolated from a fungus, stimulates hypocotyl growth and seed germination, similar to gibberellin (GA). We recently reported that helminthosporic acid (H-acid), a synthetic analog of helminthosporol, acts as an agonist of GA receptor. In this study, we showed that a H-acid analog, in which the hydroxymethyl group at the C-8 position of H-acid was converted to a keto group, acts as a selective GA receptor agonist. 1) This analog shows higher hypocotyl elongation activity in Arabidopsis than H-acid does, and induces the degradation of DELLA protein and 2) leads to the formation of the GID1-DELLA complex and 3) regulates the expression of GA-related genes. In addition, 4) its hypocotyl elongation activity was not observed in a atgid1a single mutant, and 5) this analog could promote only the interaction between specific GA receptors and DELLA proteins in vitro. Taken together, our results strongly suggest that the selectivity of the reported H-acid analog depends on the specificity of its GA receptor binding activity.
ESTHER : Miyazaki_2018_Bioorg.Med.Chem.Lett_28_2465
PubMedSearch : Miyazaki_2018_Bioorg.Med.Chem.Lett_28_2465
PubMedID: 29907394

Title : Target-based selectivity of strigolactone agonists and antagonists in plants and their potential use in agriculture - Takahashi_2018_J.Exp.Bot_69_2241
Author(s) : Takahashi I , Asami T
Ref : J Exp Bot , 69 :2241 , 2018
Abstract : Strigolactones (SLs) are small carotenoid-derived molecules that possess a wide spectrum of functions, including plant hormonal activities and chemical mediation of rhizosphere communication with both root parasitic plants and symbiotic arbuscular mycorrhizal fungi. Chemicals that regulate the functions of SLs may therefore have the potential to become widely used in agricultural applications. For example, various SL analogs and mimics have been developed to reduce the seed banks of root parasites in the field. Other analogs and mimics act selectively to suppress branching, with weak, or no stimulation, of germination in root parasites. In addition, some antagonists for SL receptors have been developed based on the mechanisms of SL perception. A better understanding of the modes of action of SL perception by various receptors will help to support the design of SL analogs, mimics, and antagonists with high activity and selectivity. Here, we review the compounds reported so far from the viewpoint of their selectivity to their targets, and the possibilities for their use in agriculture.
ESTHER : Takahashi_2018_J.Exp.Bot_69_2241
PubMedSearch : Takahashi_2018_J.Exp.Bot_69_2241
PubMedID: 29635308

Title : Methyl phenlactonoates are efficient strigolactone analogs with simple structure - Jamil_2018_J.Exp.Bot_69_2319
Author(s) : Jamil M , Kountche BA , Haider I , Guo X , Ntui VO , Jia KP , Ali S , Hameed US , Nakamura H , Lyu Y , Jiang K , Hirabayashi K , Tanokura M , Arold ST , Asami T , Al-Babili S
Ref : J Exp Bot , 69 :2319 , 2018
Abstract : Strigolactones (SLs) are a new class of phytohormones that also act as germination stimulants for root parasitic plants, such as Striga spp., and as branching factors for symbiotic arbuscular mycorrhizal fungi. Sources for natural SLs are very limited. Hence, efficient and simple SL analogs are needed for elucidating SL-related biological processes as well as for agricultural applications. Based on the structure of the non-canonical SL methyl carlactonoate, we developed a new, easy to synthesize series of analogs, termed methyl phenlactonoates (MPs), evaluated their efficacy in exerting different SL functions, and determined their affinity for SL receptors from rice and Striga hermonthica. Most of the MPs showed considerable activity in regulating plant architecture, triggering leaf senescence, and inducing parasitic seed germination. Moreover, some MPs outperformed GR24, a widely used SL analog with a complex structure, in exerting particular SL functions, such as modulating Arabidopsis roots architecture and inhibiting rice tillering. Thus, MPs will help in elucidating the functions of SLs and are promising candidates for agricultural applications. Moreover, MPs demonstrate that slight structural modifications clearly impact the efficiency in exerting particular SL functions, indicating that structural diversity of natural SLs may mirror a functional specificity.
ESTHER : Jamil_2018_J.Exp.Bot_69_2319
PubMedSearch : Jamil_2018_J.Exp.Bot_69_2319
PubMedID: 29300919

Title : Conversion of carlactone to carlactonoic acid is a conserved function of MAX1 homologs in strigolactone biosynthesis - Yoneyama_2018_New.Phytol_218_1522
Author(s) : Yoneyama K , Mori N , Sato T , Yoda A , Xie X , Okamoto M , Iwanaga M , Ohnishi T , Nishiwaki H , Asami T , Yokota T , Akiyama K , Nomura T
Ref : New Phytol , 218 :1522 , 2018
Abstract : Strigolactones (SLs) are a class of plant hormones which regulate shoot branching and function as host recognition signals for symbionts and parasites in the rhizosphere. However, steps in SL biosynthesis after carlactone (CL) formation remain elusive. This study elucidated the common and diverse functions of MAX1 homologs which catalyze CL oxidation. We have reported previously that ArabidopsisMAX1 converts CL to carlactonoic acid (CLA), whereas a rice MAX1 homolog has been shown to catalyze the conversion of CL to 4-deoxyorobanchol (4DO). To determine which reaction is conserved in the plant kingdom, we investigated the enzymatic function of MAX1 homologs in Arabidopsis, rice, maize, tomato, poplar and Selaginella moellendorffii. The conversion of CL to CLA was found to be a common reaction catalyzed by MAX1 homologs, and MAX1s can be classified into three types: A1-type, converting CL to CLA; A2-type, converting CL to 4DO via CLA; and A3-type, converting CL to CLA and 4DO to orobanchol. CLA was detected in root exudates from poplar and Selaginella, but not ubiquitously in other plants examined in this study, suggesting its role as a species-specific signal in the rhizosphere. This study provides new insights into the roles of MAX1 in endogenous and rhizosphere signaling.
ESTHER : Yoneyama_2018_New.Phytol_218_1522
PubMedSearch : Yoneyama_2018_New.Phytol_218_1522
PubMedID: 29479714

Title : Rationally Designed Strigolactone Analogs as Antagonists of the D14 Receptor - Takeuchi_2018_Plant.Cell.Physiol_59_1545
Author(s) : Takeuchi J , Jiang K , Hirabayashi K , Imamura Y , Wu Y , Xu Y , Miyakawa T , Nakamura H , Tanokura M , Asami T
Ref : Plant Cell Physiol , 59 :1545 , 2018
Abstract : Strigolactones (SLs) are plant hormones that inhibit shoot branching and act as signals in communications with symbiotic fungi and parasitic weeds in the rhizosphere. SL signaling is mediated by DWARF14 (D14), which is an alpha/beta-hydrolase that cleaves SLs into an ABC tricyclic lactone and a butenolide group (i.e. D-ring). This cleavage reaction (hydrolysis and dissociation) is important for inducing the interaction between D14 and its target proteins, including D3 and D53. In this study, a hydrolysis-resistant SL analog was predicted to inhibit the activation of the D14 receptor, thereby disrupting the SL signaling pathway. To test this prediction, carba-SL compounds, in which the ether oxygen of the D-ring or the phenol ether oxygen of the SL agonist (GR24 or 4-bromo debranone) was replaced with a methylene group, were synthesized as novel D14 antagonists. Subsequent biochemical and physiological studies indicated that carba-SLs blocked the interaction between D14 and D53 by inhibiting D14 hydrolytic activity. They also suppressed the SL-induced inhibition of rice tiller outgrowths. Additionally, carba-SLs antagonized the SL response in a Striga parasitic weed species. Structural analyses revealed that the D-ring of 7'-carba-4BD was hydrolyzed by D14 but did not dissociate from the 4BD skeleton. Thus, 7'-carba-4BD functioned as an antagonist rather than an agonist. Thus, the hydrolysis of the D-ring of SLs may be insufficient for activating the receptor. This study provides data relevant to designing SL receptor antagonists.
ESTHER : Takeuchi_2018_Plant.Cell.Physiol_59_1545
PubMedSearch : Takeuchi_2018_Plant.Cell.Physiol_59_1545
PubMedID: 29727000
Gene_locus related to this paper: arath-AtD14 , arath-KAI2.D14L

Title : Synthetic strigolactone analogues reveal anti-cancer activities on hepatocellular carcinoma cells - Hasan_2018_Bioorg.Med.Chem.Lett_28_1077
Author(s) : Hasan MN , Choudhry H , Razvi SS , Moselhy SS , Kumosani TA , Zamzami MA , Omran Z , Halwani MA , Al-Babili S , Abualnaja KO , Al-Malki AL , Alhosin M , Asami T
Ref : Bioorganic & Medicinal Chemistry Lett , 28 :1077 , 2018
Abstract : Hepatocellular carcinoma (HCC) remains one of the leading causes of death worldwide. The complex etiology is attributed to many factors like heredity, cirrhosis, hepatitis infections or the dysregulation of the different molecular pathways. Nevertheless, the current treatment regimens have either severe side effects or tumors gradually acquire resistance upon prolonged use. Thus, developing a new selective treatment for HCC is the need of the hour. Many anticancer agents derived from plants have been evaluated for their cytotoxicity towards many human cancer cell lines. Strigolactones (SLs)-a newly discovered class of phytohormones, play a crucial role in the development of plant-root and shoot. Recently, many synthetic analogues of SLs have demonstrated pro-apoptotic effects on different cancer cell lines like prostate, breast, colon and lung. In this study, we tested synthetic SLs analogues on HCC cell line-HepG2 and evaluated their capability to induce cell proliferation inhibition and apoptosis. Primary WST-1 assays, followed by annexin-V/7AAD staining, demonstrated the anti-proliferative effects. The SLs analogues TIT3 and TIT7 were found to significantly reduce HepG2 cell viability in a dose- and time-dependent manner and induce apoptosis. Interestingly, though TIT3 and TIT7 strongly affected cancer cell proliferation, both compounds showed moderate anti-proliferative effect on normal cells. Further, migration of cancer cells was suppressed upon treatment with TIT3 and TIT7 in a wound healing assay. In summary, these findings suggest that two SLs analogues TIT3 and TIT7 exert selective inhibitory effects on cancer cells most likely through targeting microtubules. SLs analogues could be used in future as potential anti-cancer candidates in chemotherapy.
ESTHER : Hasan_2018_Bioorg.Med.Chem.Lett_28_1077
PubMedSearch : Hasan_2018_Bioorg.Med.Chem.Lett_28_1077
PubMedID: 29456109

Title : Involvement of STH7 in light-adapted development in Arabidopsis thaliana promoted by both strigolactone and karrikin - Thussagunpanit_2017_Biosci.Biotechnol.Biochem_81_292
Author(s) : Thussagunpanit J , Nagai Y , Nagae M , Mashiguchi K , Mitsuda N , Ohme-Takagi M , Nakano T , Nakamura H , Asami T
Ref : Biosci Biotechnol Biochem , 81 :292 , 2017
Abstract : Strigolactones (SLs) and karrikins (KARs) regulate photomorphogenesis. GR24, a synthetic SL and KAR1, a KAR, inhibit the hypocotyl elongation of Arabidopsis thaliana in a weak light. GR24 and KAR1 up-regulate the expression of STH7, encoding a transcription factor belonging to the double B-box zinc finger subfamily. In this study, we used STH7-overexpressing (STH7ox) lines and functionally defective STH7 (STH7-SRDX) mutants to investigate roles of SLs and KARs in photomorphogenesis of Arabidopsis. Hypocotyl elongation of STH7-SRDX mutants was less sensitive to both GR24 and KAR1 treatment than that of wild-type Arabidopsis under weak light conditions. Furthermore, the chlorophyll and anthocyanin content was increased in STH7ox lines when de-etiolated with light and GR24-treated plants had enhanced anthocyanin production. GR24 and KAR1 treatment significantly increased the expression level of photosynthesis-related genes LHCB1 and rbcS. The results strongly suggest that SL and KAR induce photomorphogenesis of Arabidopsis in an STH7-dependent manner.
ESTHER : Thussagunpanit_2017_Biosci.Biotechnol.Biochem_81_292
PubMedSearch : Thussagunpanit_2017_Biosci.Biotechnol.Biochem_81_292
PubMedID: 27858514

Title : A Taylor-Made Design of Phenoxyfuranone-Type Strigolactone Mimic - Fukui_2017_Front.Plant.Sci_8_936
Author(s) : Fukui K , Yamagami D , Ito S , Asami T
Ref : Front Plant Sci , 8 :936 , 2017
Abstract : Strigolactones are a class of plant hormones that inhibit axillary bud outgrowth and are released from plant roots to act as a rhizosphere communication signal. The Orobanchaceae parasitic plant Striga hermonthica perceives strigolactone as its germination signal, indicating host presence. After germination, the Striga plant parasitises the host plant and suppresses host growth by draining photosynthetic products, water and other essential nutrients. Because of this way of life, this parasite threatens crop production in sub-Saharan Africa with infestation in crop fields and crop devastation. Crop protection in such areas is among the most concerning problems to be dealt with as immediately as possible. With respect to crop protection from Striga, many strigolactone agonists have been developed and used in research to reveal Striga biology, and have contributed to development of crop protection methods. However, an effective method has yet to be found. In a previous study, we reported debranones as a group of strigolactone mimics that inhibit axillary buds outgrowth with moderate stimulation activity for Striga germination. Debranones would be accessible because they are simply synthesized from commercially available phenols and bromo butenolide. Taking this advantage of debranones for Striga research, we tried to find the debranones stimulating Striga seed germination. To modulate functional selectivity and to enhance germination inducing activity of debranones, we studied structure-activity relationships. We investigated effects of substituent position and functional group on debranone activity and selectivity as a strigolactone mimic. As a result, we improved stimulation activity of debranones for Striga seed germination by chemical modification, and demonstrated the pharmacophore of debranones for selective modulation of distinct strigolactone responses.
ESTHER : Fukui_2017_Front.Plant.Sci_8_936
PubMedSearch : Fukui_2017_Front.Plant.Sci_8_936
PubMedID: 28676802

Title : Chemical modification of a phenoxyfuranone-type strigolactone mimic for selective effects on rice tillering or Striga hermonthica seed germination - Takahashi_2016_Pest.Manag.Sci_72_2048
Author(s) : Takahashi I , Fukui K , Asami T
Ref : Pest Manag Sci , 72 :2048 , 2016
Abstract : BACKGROUND: We previously reported that a series of phenoxyfuranone compounds, designated 'debranones', mimic strigolactone (SL) activity. 4-Bromodebranone (4BD) is a functionally selective SL mimic that reduces the number of shoot branches on rice more potently than GR24, a typical synthetic SL analogue, but does not induce seed germination in the root-parasitic plant Striga hermonthica. To enhance the selective activity of debranones in stimulating the seed germination of root-parasitic plants, we prepared several analogues of 4BD in which the chlorine atom was substituted with an H atom at the o-, m- or p-position on the phenyl ring (designated 2-, 3-, or 4-chlorodebranone, respectively) or had a bicyclic group instead of the phenyl ring. We evaluated the biological activities of the compounds with rice tillering assays and S. hermonthica seed germination assays. RESULTS: Both assays showed that the substituent position affected debranone efficiency, and among the monochlorodebranones, 2-chlorodebranone was more effective than the other two isomers in both assays. When the activities of the bicyclic debranones were compared in the same two assays, one was more active than GR24 in the rice tillering assay. This debranone also stimulated the germination of S. hermonthica seeds. Thus, some debranone derivatives induced the germination of S. hermonthica seeds, although their activities were still approximately 1/20 that of GR24. CONCLUSION: These results strongly suggest that further and rigorous structure-activity relationship studies of the debranones will identify derivatives that more potently stimulate the suicidal germination of S. hermonthica seeds. (c) 2016 Society of Chemical Industry.
ESTHER : Takahashi_2016_Pest.Manag.Sci_72_2048
PubMedSearch : Takahashi_2016_Pest.Manag.Sci_72_2048
PubMedID: 26929041

Title : Structural basis of unique ligand specificity of KAI2-like protein from parasitic weed Striga hermonthica - Xu_2016_Sci.Rep_6_31386
Author(s) : Xu Y , Miyakawa T , Nakamura H , Nakamura A , Imamura Y , Asami T , Tanokura M
Ref : Sci Rep , 6 :31386 , 2016
Abstract : The perception of two plant germination inducers, karrikins and strigolactones, are mediated by the proteins KAI2 and D14. Recently, KAI2-type proteins from parasitic weeds, which are possibly related to seed germination induced by strigolactone, have been classified into three clades characterized by different responses to karrikin/strigolactone. Here we characterized a karrikin-binding protein in Striga (ShKAI2iB) that belongs to intermediate-evolving KAI2 and provided the structural bases for its karrikin-binding specificity. Binding assays showed that ShKAI2iB bound karrikins but not strigolactone, differing from other KAI2 and D14. The crystal structures of ShKAI2iB and ShKAI2iB-karrikin complex revealed obvious structural differences in a helix located at the entry of its ligand-binding cavity. This results in a smaller closed pocket, which is also the major cause of ShKAI2iB's specificity of binding karrikin. Our structural study also revealed that a few non-conserved amino acids led to the distinct ligand-binding profile of ShKAI2iB, suggesting that the evolution of KAI2 resulted in its diverse functions.
ESTHER : Xu_2016_Sci.Rep_6_31386
PubMedSearch : Xu_2016_Sci.Rep_6_31386
PubMedID: 27507097
Gene_locus related to this paper: strhe-ShHTL3

Title : Discovery and identification of 2-methoxy-1-naphthaldehyde as a novel strigolactone-signaling inhibitor - Mashita_2016_J.Pestic.Sci_41_71
Author(s) : Mashita O , Koishihara H , Fukui K , Nakamura H , Asami T
Ref : J Pestic Sci , 41 :71 , 2016
Abstract : Knowledge about strigolactone biosynthesis and signaling is increasing and the crystal structure of strigolactone receptor protein D14 has been resolved. Although a variety of strigolactone biosynthesis inhibitors and strigolactone agonists are known, no inhibitors of strigolactone signaling have been reported. Here, we conducted virtual screening in silico to identify chemical regulators that inhibit SL reception. We used LigandScout to analyze a pharmacophore model based on structural information about D14 protein and complex D14-D-OH (a hydrolysis product of strigolactone formed by D14). We identified a candidate compound, XM-47, and confirmed that it inhibits D14-SLR1 and D14-D53 interactions. A possible product of XM-47 hydrolysis, 2-methoxy-1-naphthaldehyde (2-MN), inhibits D14-SLR1 and D14-D53 interactions and restores the growth of rice tillering buds suppressed by strigolactone.
ESTHER : Mashita_2016_J.Pestic.Sci_41_71
PubMedSearch : Mashita_2016_J.Pestic.Sci_41_71
PubMedID: 30363101

Title : Development of Inhibitors of Salicylic Acid Signaling - Jiang_2015_J.Agric.Food.Chem_63_7124
Author(s) : Jiang K , Kurimoto T , Seo EK , Miyazaki S , Nakajima M , Nakamura H , Asami T
Ref : Journal of Agricultural and Food Chemistry , 63 :7124 , 2015
Abstract : Salicylic acid (SA) plays important roles in the induction of systemic acquired resistance (SAR) in plants. Determining the mechanism of SAR will extend our understanding of plant defenses against pathogens. We recently reported that PAMD is an inhibitor of SA signaling, which suppresses the expression of the pathogenesis-related PR genes and is expected to facilitate the understanding of SA signaling. However, PAMD strongly inhibits plant growth. To minimize the side effects of PAMD, we synthesized a number of PAMD derivatives, and identified compound 4 that strongly suppresses the expression of the PR genes with fewer adverse effects on plant growth than PAMD. We further showed that the adverse effects on plant growth were partially caused the stabilization of DELLA, which is also related to the pathogen responses. These results indicate that compound 4 would facilitate our understanding of SA signaling and its cross talk with other plant hormones.
ESTHER : Jiang_2015_J.Agric.Food.Chem_63_7124
PubMedSearch : Jiang_2015_J.Agric.Food.Chem_63_7124
PubMedID: 26236918

Title : Target sites for chemical regulation of strigolactone signaling - Nakamura_2014_Front.Plant.Sci_5_623
Author(s) : Nakamura H , Asami T
Ref : Front Plant Sci , 5 :623 , 2014
Abstract : Demands for plant growth regulators (PGRs; chemicals that control plant growth) are increasing globally, especially in developing countries. Both positive and negative PGRs are widely used to enhance crop production and to suppress unwanted shoot growth, respectively. Strigolactones (SLs) are multifunctional molecules that function as phytohormones, inhibiting shoot branching and also functioning in the rhizospheric communication with symbiotic fungi and parasitic weeds. Therefore, it is anticipated that chemicals that regulate the functions of SLs will be widely used in agricultural applications. Although the SL biosynthetic pathway is not fully understood, it has been demonstrated that beta-carotene isomerases, carotenoid cleavage dioxygenases (CCDs), and a cytochrome P450 monooxygenase are involved in strigolactone biosynthesis. A CCD inhibitor, abamine, which is also an inhibitor of abscisic acid biosynthesis, reduces the levels of SL in several plant species and reduces the germination rate of Orobanche minor seeds grown with tobacco. On the basis of the structure of abamine, several chemicals have been designed to specifically inhibit CCDs during SL synthesis. Cytochrome P450 monooxygenase is another target enzyme in the development of SL biosynthesis inhibitors, and the triazole-derived TIS series of chemicals is known to include SL biosynthesis inhibitors, although their target enzyme has not been identified. Recently, DWARF14 (D14) has been shown to be a receptor for SLs, and the D-ring moiety of SL is essential for its recognition by D14. A variety of SL agonists are currently under development and most agonists commonly contain the D-ring or a D-ring-like moiety. Several research groups have also resolved the crystal structure of D14 in the last two years. It is expected that this information on the D14 structure will be invaluable not only for developing SL agonists with novel structures but also in the design of inhibitors of SL receptors.
ESTHER : Nakamura_2014_Front.Plant.Sci_5_623
PubMedSearch : Nakamura_2014_Front.Plant.Sci_5_623
PubMedID: 25414720

Title : Chemical screening of an inhibitor for gibberellin receptors based on a yeast two-hybrid system - Yoon_2013_Bioorg.Med.Chem.Lett_23_1096
Author(s) : Yoon JM , Nakajima M , Mashiguchi K , Park SH , Otani M , Asami T
Ref : Bioorganic & Medicinal Chemistry Lett , 23 :1096 , 2013
Abstract : We applied a yeast two-hybrid (Y2H) system to the high-throughput monitoring of two proteins' interaction, a receptor for phytohormone gibberellin (GA) and its direct signal transducer DELLA. With this system, we screened inhibitors to the interaction. As a result, we discovered a chemical, 3-(2-thienylsulfonyl)pyrazine-2-carbonitrile (TSPC), and we confirmed that TSPC is an inhibitor for GA perception by in vitro and in planta evaluations.
ESTHER : Yoon_2013_Bioorg.Med.Chem.Lett_23_1096
PubMedSearch : Yoon_2013_Bioorg.Med.Chem.Lett_23_1096
PubMedID: 23298808

Title : D14-SCFD3-dependent degradation of D53 regulates strigolactone signalling - Zhou_2013_Nature_504_406
Author(s) : Zhou F , Lin Q , Zhu L , Ren Y , Zhou K , Shabek N , Wu F , Mao H , Dong W , Gan L , Ma W , Gao H , Chen J , Yang C , Wang D , Tan J , Zhang X , Guo X , Wang J , Jiang L , Liu X , Chen W , Chu J , Yan C , Ueno K , Ito S , Asami T , Cheng Z , Lei C , Zhai H , Wu C , Wang H , Zheng N , Wan J
Ref : Nature , 504 :406 , 2013
Abstract : Strigolactones (SLs), a newly discovered class of carotenoid-derived phytohormones, are essential for developmental processes that shape plant architecture and interactions with parasitic weeds and symbiotic arbuscular mycorrhizal fungi. Despite the rapid progress in elucidating the SL biosynthetic pathway, the perception and signalling mechanisms of SL remain poorly understood. Here we show that DWARF 53 (D53) acts as a repressor of SL signalling and that SLs induce its degradation. We find that the rice (Oryza sativa) d53 mutant, which produces an exaggerated number of tillers compared to wild-type plants, is caused by a gain-of-function mutation and is insensitive to exogenous SL treatment. The D53 gene product shares predicted features with the class I Clp ATPase proteins and can form a complex with the alpha/beta hydrolase protein DWARF 14 (D14) and the F-box protein DWARF 3 (D3), two previously identified signalling components potentially responsible for SL perception. We demonstrate that, in a D14- and D3-dependent manner, SLs induce D53 degradation by the proteasome and abrogate its activity in promoting axillary bud outgrowth. Our combined genetic and biochemical data reveal that D53 acts as a repressor of the SL signalling pathway, whose hormone-induced degradation represents a key molecular link between SL perception and responses.
ESTHER : Zhou_2013_Nature_504_406
PubMedSearch : Zhou_2013_Nature_504_406
PubMedID: 24336215

Title : Molecular mechanism of strigolactone perception by DWARF14 - Nakamura_2013_Nat.Commun_4_2613
Author(s) : Nakamura H , Xue YL , Miyakawa T , Hou F , Qin HM , Fukui K , Shi X , Ito E , Ito S , Park SH , Miyauchi Y , Asano A , Totsuka N , Ueda T , Tanokura M , Asami T
Ref : Nat Commun , 4 :2613 , 2013
Abstract : Strigolactones (SLs) are phytohormones that inhibit shoot branching and function in the rhizospheric communication with symbiotic fungi and parasitic weeds. An alpha/beta-hydrolase protein, DWARF14 (D14), has been recognized to be an essential component of plant SL signalling, although its precise function remains unknown. Here we present the SL-dependent interaction of D14 with a gibberellin signalling repressor SLR1 and a possible mechanism of phytohormone perception in D14-mediated SL signalling. D14 functions as a cleavage enzyme of SLs, and the cleavage reaction induces the interaction with SLR1. The crystal structure of D14 shows that 5-hydroxy-3-methylbutenolide (D-OH), which is a reaction product of SLs, is trapped in the catalytic cavity of D14 to form an altered surface. The D14 residues recognizing D-OH are critical for the SL-dependent D14-SLR1 interaction. These results provide new insight into crosstalk between gibberellin and SL signalling pathways.
ESTHER : Nakamura_2013_Nat.Commun_4_2613
PubMedSearch : Nakamura_2013_Nat.Commun_4_2613
PubMedID: 24131983
Gene_locus related to this paper: orysj-Q10QA5

Title : An unusual spliced variant of DELLA protein, a negative regulator of gibberellin signaling, in lettuce - Sawada_2012_Biosci.Biotechnol.Biochem_76_544
Author(s) : Sawada Y , Umetsu A , Komatsu Y , Kitamura J , Suzuki H , Asami T , Fukuda M , Honda I , Mitsuhashi W , Nakajima M , Toyomasu T
Ref : Biosci Biotechnol Biochem , 76 :544 , 2012
Abstract : DELLA proteins are negative regulators of the signaling of gibberellin (GA), a phytohormone regulating plant growth. DELLA degradation is triggered by its interaction with GID1, a soluble GA receptor, in the presence of bioactive GA. We isolated cDNA from a spliced variant of LsDELLA1 mRNA in lettuce, and named it LsDELLA1sv. It was deduced that LsDELLA1sv encodes truncated LsDELLA1, which has DELLA and VHYNP motifs at the N terminus but lacks part of the C-terminal GRAS domain. The recombinant LsDELLA1sv protein interacted with both Arabidopsis GID1 and lettuce GID1s in the presence of GA. A yeast two-hybrid assay suggested that LsDELLA1sv interacted with LsDELLA1. The ratio of LsDELLA1sv to LsDELLA1 transcripts was higher in flower samples at the late reproductive stage and seed samples (dry seeds and imbibed seeds) than in the other organ samples examined. This study suggests that LsDELLA1sv is a possible modulator of GA signaling in lettuce.
ESTHER : Sawada_2012_Biosci.Biotechnol.Biochem_76_544
PubMedSearch : Sawada_2012_Biosci.Biotechnol.Biochem_76_544
PubMedID: 22451398

Title : Effects of triazole derivatives on strigolactone levels and growth retardation in rice - Ito_2011_PLoS.One_6_e21723
Author(s) : Ito S , Umehara M , Hanada A , Kitahata N , Hayase H , Yamaguchi S , Asami T
Ref : PLoS ONE , 6 :e21723 , 2011
Abstract : We previously discovered a lead compound for strigolactone (SL) biosynthesis inhibitors, TIS13 (2,2-dimethyl-7-phenoxy-4-(1H-1,2,4-triazol-1-yl)heptan-3-ol). Here, we carried out a structure-activity relationship study of TIS13 to discover more potent and specific SL biosynthesis inhibitor because TIS13 has a severe side effect at high concentrations, including retardation of the growth of rice seedlings. TIS108, a new TIS13 derivative, was found to be a more specific SL biosynthesis inhibitor than TIS13. Treatment of rice seedlings with TIS108 reduced SL levels in both roots and root exudates in a concentration-dependent manner and did not reduce plant height. In addition, root exudates of TIS108-treated rice seedlings stimulated Striga germination less than those of control plants. These results suggest that TIS108 has a potential to be applied in the control of root parasitic weeds germination.
ESTHER : Ito_2011_PLoS.One_6_e21723
PubMedSearch : Ito_2011_PLoS.One_6_e21723
PubMedID: 21760901

Title : New branching inhibitors and their potential as strigolactone mimics in rice - Fukui_2011_Bioorg.Med.Chem.Lett_21_4905
Author(s) : Fukui K , Ito S , Ueno K , Yamaguchi S , Kyozuka J , Asami T
Ref : Bioorganic & Medicinal Chemistry Lett , 21 :4905 , 2011
Abstract : Strigolactones (SLs) are rhizosphere communication chemicals. Recent studies of highly branched mutants revealed that SL or its metabolites work as a phytohormone to inhibit shoot branching. When SLs are exogenously applied to the rice d10-1 mutant that has a highly branched phenotype caused by a defect in the SL biosynthesis gene (CCD8), they inhibit tiller bud outgrowth (branching in rice) of the mutant. We focused our attention on the SL function as a phytohormone and tried to find new chemicals mimicking the hormonal action of SL by screening chemicals that inhibit branching of rice d10-1 mutant. Fortunately, we found 5-(4-chlorophenoxy)-3-methylfuran-2(5H)-one (3a) as a new chemical possessing SL-like activity against the rice d10-1 mutant. Then, we prepared several derivatives of 3a (3b-3k) to examine their ability to inhibit shoot branching of rice d10-1. These derivatives were synthesized by a one-pot coupling reaction between phenols and halo butenolide to give 5-phenoxy 3-methylfuran-2(5H)-one (3) derivatives, which possess a common substructure with SLs. Some of the derivatives showed SL-like activity more potently than GR24, a typical SL derivative, in a rice assay. As SLs also show activity by inducing seed germination of root parasitic plants, the induction activity of these derivatives was also evaluated. Here we report the structure-activity relationships of these compounds.
ESTHER : Fukui_2011_Bioorg.Med.Chem.Lett_21_4905
PubMedSearch : Fukui_2011_Bioorg.Med.Chem.Lett_21_4905
PubMedID: 21741836

Title : A new lead chemical for strigolactone biosynthesis inhibitors - Ito_2010_Plant.Cell.Physiol_51_1143
Author(s) : Ito S , Kitahata N , Umehara M , Hanada A , Kato A , Ueno K , Mashiguchi K , Kyozuka J , Yoneyama K , Yamaguchi S , Asami T
Ref : Plant Cell Physiol , 51 :1143 , 2010
Abstract : Several triazole-containing chemicals have previously been shown to act as efficient inhibitors of cytochrome P450 monooxygenases. To discover a strigolactone biosynthesis inhibitor, we screened a chemical library of triazole derivatives to find chemicals that induce tiller bud outgrowth of rice seedlings. We discovered a triazole-type chemical, TIS13 [2,2-dimethyl-7-phenoxy-4-(1H-1,2,4-triazol-1-yl)heptan-3-ol], which induced outgrowth of second tiller buds of wild-type seedlings, as observed for non-treated strigolactone-deficient d10 mutant seedlings. TIS13 treatment reduced strigolactone levels in both roots and root exudates in a concentration-dependent manner. Co-application of GR24, a synthetic strigolactone, with TIS13 canceled the TIS13-induced tiller bud outgrowth. Taken together, these results indicate that TIS13 inhibits strigolactone biosynthesis in rice seedlings. We propose that TIS13 is a new lead compound for the development of specific strigolactone biosynthesis inhibitors.
ESTHER : Ito_2010_Plant.Cell.Physiol_51_1143
PubMedSearch : Ito_2010_Plant.Cell.Physiol_51_1143
PubMedID: 20522488

Title : Differential expression and affinities of Arabidopsis gibberellin receptors can explain variation in phenotypes of multiple knock-out mutants - Suzuki_2009_Plant.J_60_48
Author(s) : Suzuki H , Park SH , Okubo K , Kitamura J , Ueguchi-Tanaka M , Iuchi S , Katoh E , Kobayashi M , Yamaguchi I , Matsuoka M , Asami T , Nakajima M
Ref : Plant J , 60 :48 , 2009
Abstract : In Arabidopsis, three receptors exist for the phytohormone gibberellin. Of the three, only a double loss-of-function mutant (atgid1a atgid1c) shows a dwarf phenotype, while other double and all single mutants show no abnormality in height. In this study we show that the expression of AtGID1b-GUS mRNA, driven by the AtGID1b promoter, is low in inflorescence stems, but may be 10% of AtGID1a-GUS mRNA, driven by the AtGID1a promoter. However, AtGID1b-GUS enzymatic activity does not exist in them. This factor strongly suggests that atgid1a atgid1c lacks sufficient AtGID1b protein for normal stem growth. In the stamens of pAtGID1c::AtGID1c-GUS transformants, we detected clear AtGID1c-GUS activity, while another atgid1a atgid1b, which has short stamens in its flowers, causes the adhesion of little pollen to stigmas thus leading to its low fertility. We then evaluated the affinity of the AtGID1-DELLA interaction by a competitive yeast three-hybrid system and also by QCM apparatus. AtGID1c showed a quite lower affinity to RGL2, the major DELLA protein in floral buds, than AtGID1a or AtGID1b. The low affinity of the AtGID1c-RGL2 interaction is likely to be responsible for the failure of AtGID1c to hold RGL2, which is required for normal stamen development. Taken together with expressional information of DELLA genes, we propose that in a double loss-of-function mutant of gibberellin receptors, the emergence of any phenotype(s) depends on the abundance of the remaining receptor and its preference to DELLA proteins existing at a target site.
ESTHER : Suzuki_2009_Plant.J_60_48
PubMedSearch : Suzuki_2009_Plant.J_60_48
PubMedID: 19500306
Gene_locus related to this paper: arath-AT5G27320 , arath-GID1B

Title : Multiple loss-of-function of Arabidopsis gibberellin receptor AtGID1s completely shuts down a gibberellin signal - Iuchi_2007_Plant.J_50_958
Author(s) : Iuchi S , Suzuki H , Kim YC , Iuchi A , Kuromori T , Ueguchi-Tanaka M , Asami T , Yamaguchi I , Matsuoka M , Kobayashi M , Nakajima M
Ref : Plant J , 50 :958 , 2007
Abstract : Arabidopsis carries three receptor genes for the phytohormone gibberellin (GA), AtGID1a, AtGID1b and AtGID1c. Expression of each gene in the rice gid1-1 mutant for GA receptors causes reversion of its severely dwarfed phenotype and GA insensitivity to a normal level, even though each loss-of-function mutant shows no clear phenotype in Arabidopsis (Nakajima et al., 2006). In this paper, we report the functional redundancy and specificity of each AtGID1 by analyzing the multiple mutants for loss of function. Seeds of the double knockout mutants atgid1a atgid1b, atgid1a atgid1c and atgid1b atgid1c germinated normally. The double knockout mutant atgid1a atgid1c showed a dwarf phenotype, while other double mutants were of normal height compared to the wild-type. The stamens of the double knockout mutant atgid1a atgid1b were significantly shorter than those of the wild-type, and this leads to low fertility. A severe disarrangement of the pattern on its seed surface was also observed. The triple knockout mutant atgid1a atgid1b atgid1c did not germinate voluntarily, and only started to grow when the seed coat was peeled off after soaking. Seedlings of the triple knockout mutants were severe dwarfs, only a few millimeters high after growing for 1 month. Moreover, the triple knockout seedlings completely lost their ability to respond to exogenously applied GA. These results show that all AtGID1s function as GA receptors in Arabidopsis, but have specific role(s) for growth and development.
ESTHER : Iuchi_2007_Plant.J_50_958
PubMedSearch : Iuchi_2007_Plant.J_50_958
PubMedID: 17521411
Gene_locus related to this paper: arath-AT5G27320 , arath-GID1B

Title : Preparation and biological activity of molecular probes to identify and analyze jasmonic acid-binding proteins - Jikumaru_2004_Biosci.Biotechnol.Biochem_68_1461
Author(s) : Jikumaru Y , Asami T , Seto H , Yoshida S , Yokoyama T , Obara N , Hasegawa M , Kodama O , Nishiyama M , Okada K , Nojiri H , Yamane H
Ref : Biosci Biotechnol Biochem , 68 :1461 , 2004
Abstract : Several types of jasomonic acid (JA) derivatives, including JA--amino acid conjugates, a JA--biotin conjugate, a JA--dexamethasone heterodimer, and a JA-fluoresceine conjugate, were prepared as candidates for molecular probes to identify JA--binding proteins. These JA derivatives, excepting the JA--fluoresceine conjugate, exhibited significant biological activities in a rice seedling assay, a rice phytoalexin-inducing assay, and/or a soybean phenylalanine ammonia-lyase-inducing assay. These JA derivatives could therefore be useful probes for identifying JA--binding proteins. The activity spectra of the prepared compounds were different from each other, suggesting that different types of JA receptors were involved in the perception of JA derivatives in the respective bioassays.
ESTHER : Jikumaru_2004_Biosci.Biotechnol.Biochem_68_1461
PubMedSearch : Jikumaru_2004_Biosci.Biotechnol.Biochem_68_1461
PubMedID: 15277750