Physcomitrella patens subsp. patens (Moss) PpKAI2-like H Predicted protein
Comment
PpKAI2L-H cleaves both (-)-GR24 and (+)-GR24. PpKAI2L-H on (+/-)-GC242 is explained by the presence of a specific leucine residue Leu28 instead of the phenylalanine found in AtD14 (Phe26)
(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Eukaryota: NE > Viridiplantae: NE > Streptophyta: NE > Streptophytina: NE > Embryophyta: NE > Bryophyta: NE > Bryophytina: NE > Bryopsida: NE > Funariidae: NE > Funariales: NE > Funariaceae: NE > Physcomitrella: NE > Physcomitrella patens: NE
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA MPSPLLSTHNVTVLGNRSDPVVVLGHGLGTDQSVWKYTVPSLVNQNFQVV LYDTMGAGSTETSDFNFKRYSSLQGHVDDLLAILDELEIENCVYVGHSMS GMIGVLASLERPDLFRKLILLSASPRYLNDSSYYGGFEQEDLDQLFSSMR SNFSAWVSGFATAAVGTDIHDEAVQEFSSTFISMRPDVALRTSQFVFQSD FRSILSEVTVPCHIVQSRKDIAVPIEVAEYLRCNLGGWTSVDILQTDGHL PQLSCPELVVPVLLHCIDS
In angiosperms, the alpha/beta hydrolase DWARF14 (D14), along with the F-box protein MORE AXILLARY GROWTH2 (MAX2), perceives strigolactones (SL) to regulate developmental processes. The key SL biosynthetic enzyme CAROTENOID CLEAVAGE DIOXYGENASE8 (CCD8) is present in the moss Physcomitrium patens, and PpCCD8-derived compounds regulate moss extension. The PpMAX2 homolog is not involved in the SL response, but 13 PpKAI2LIKE (PpKAI2L) genes homologous to the D14 ancestral paralog KARRIKIN INSENSITIVE2 (KAI2) encode candidate SL receptors. In Arabidopsis thaliana, AtKAI2 perceives karrikins and the elusive endogenous KAI2-Ligand (KL). Here, germination assays of the parasitic plant Phelipanche ramosa suggested that PpCCD8-derived compounds are likely non-canonical SLs. (+)-GR24 SL analog is a good mimic for PpCCD8-derived compounds in P. patens, while the effects of its enantiomer (-)-GR24, a KL mimic in angiosperms, are minimal. Interaction and binding assays of seven PpKAI2L proteins pointed to the stereoselectivity towards (-)-GR24 for a single clade of PpKAI2L (eu-KAI2). Enzyme assays highlighted the peculiar behavior of PpKAI2L-H. Phenotypic characterization of Ppkai2l mutants showed that eu-KAI2 genes are not involved in the perception of PpCCD8-derived compounds but act in a PpMAX2-dependent pathway. By contrast, mutations in PpKAI2L-G, and -J genes abolished the response to the (+)-GR24 enantiomer, suggesting that PpKAI2L-G, and -J proteins are receptors for moss SLs.
Published as a preprint Lopez-Obando_2020_Biorxiv__
In plants, strigolactones are perceived by the dual receptor-hydrolase DWARF14 (D14). D14 belongs to the superfamily of alpha/beta hydrolases and is structurally similar to the karrikin receptor KARRIKIN INSENSITIVE 2 (KAI2). The moss Physcomitrella patens is an ideal model system for studying this receptor family, because it includes 11 highly related family members with unknown ligand specificity. We present the crystal structures of three Physcomitrella D14/KAI2-like proteins and describe a loop-based mechanism that leads to a permanent widening of the hydrophobic substrate gorge. We have identified protein clades that specifically perceive the karrikin KAR1 and the non-natural strigolactone isomer (-)-5-deoxystrigol in a highly stereoselective manner.
We report the draft genome sequence of the model moss Physcomitrella patens and compare its features with those of flowering plants, from which it is separated by more than 400 million years, and unicellular aquatic algae. This comparison reveals genomic changes concomitant with the evolutionary movement to land, including a general increase in gene family complexity; loss of genes associated with aquatic environments (e.g., flagellar arms); acquisition of genes for tolerating terrestrial stresses (e.g., variation in temperature and water availability); and the development of the auxin and abscisic acid signaling pathways for coordinating multicellular growth and dehydration response. The Physcomitrella genome provides a resource for phylogenetic inferences about gene function and for experimental analysis of plant processes through this plant's unique facility for reverse genetics.
Physcomitrella patens subsp. patens (Moss) PpKAI2-like H Predicted protein
