Genome-wide identification and characterization of heat shock protein superfamily in the cotton aphid Aphis gossypii: phylogenetic, structural, and expression profiles analyses.

The cotton aphid, Aphis gossypii, belonging to Hemiptera Aphididae is a worldwide pest on various plants. This pest is particularly notorious for its high tolerance to both temperature and insecticides. Heat shock proteins (HSPs), which have been recognized as molecular chaperones, play pivotal roles in the response of insects to environmental stress. However, information on HSP genes in A. gossypii and their expression response remain limited. In this study, 50 HSP genes were identified in the A. gossypii genome, including 3 HSP90s, 15 HSP70s, 11 HSP60s, 19 HSP40s and 2 sHSPs. Phylogenetic analysis strongly supported the family classification of A. gossypii HSP genes. All of the AgHSPs were distributed across four chromosomes, and several gene duplication events were observed. Transcriptome data revealed that most AgHSPs could be induced by short-term high temperature treatment. Conversely, most HSPs decreased their transcription levels under long-term high temperature exposure. Notably, three HSPs (AgHSP40-9-X2, AgHSP40-15 and AgHSP70-8) were consistently up-regulated after insecticide exposure in both susceptible and resistant populations. Moreover, the expressions of HSPs across several morphs of aphids were systematically evaluated for the first time. Our findings provide fundamental data for future studies and enhance our understanding of the roles of HSPs in environmental stress adaptation in A. gossypii.