Pan_2014_Comp.Biochem.Physiol.Part.D.Genomics.Proteomics_13C_10

A thiamethoxam-resistant strain of cotton aphid (ThR) strain displayed a 19.35-fold greater resistance to thiamethoxam compared to a susceptible cotton aphid (SS) strain. Solexa sequencing technology was used to investigate differentially expressed genes (DEGs) in cotton aphids in the context of thiamethoxam resistance. A total of 22,569,311 and 21,317,732 clean reads were obtained from the ThR and SS transcriptomes, respectively, and assembled into 35,222 non-redundant (Nr) consensus sequences. The expression of 620 unigenes changed significantly in the ThR libraries compared to the SS strain; 349 genes were up-regulated, and 271 genes were down-regulated (P<=0.001). Expression levels of ribosomal proteins, ATP synthase, cytochrome c oxidase, ecdysteroid UDP-glucosyltransferase and esterase were up-regulated significantly in the ThR strain compared to the SS strain. The genes of cuticle proteins, salivary proteins, and fibroin heavy chain decreased dramatically. One nicotinic acetylcholine receptor (nAChR) alpha subunit was down-regulated in the ThR strain. The expression levels of 10 differentially expressed unigenes were confirmed using real-time RT-PCR, and the observed trends in gene expression matched the Solexa expression profiles. Specific single-nucleotide polymorphisms (SNPs) in nAChRs that cause amino acid substitution were found from the ThR and SS stains respectively. These data illustrate that genetic changes in nAChR genes and up-regulated ribosomal proteins, ecdysteroid UDP-glucosyltransferase, cytochrome c oxidase, esterase and peroxidase may confer the tolerance of resistant cotton aphids to thiamethoxam.