Genome-wide analyses of glutathione S-transferase gene family and expression profiling among three haplotypes Aphis gossypii

Glutathione S-transferase (GST) plays a critical role in detoxifying various chemical compounds and is essential for host adaptation and pesticide resistance in insects. To understand the genetic structure of the GST family and the expression patterns among three haplotypes of Aphis gossypii, we conducted studies using genome annotation files and RNA-seq data. We identified 11 GSTs in A. gossypii, which include 2 microsomal GSTs, 2 in the Theta class, 2 in the Delta class, 3 in the Sigma class (one of which contains a probable pseudogene), 1 in the Omega class, and 1 belonging to a GST C-terminal domain-containing protein. These GSTs are distributed on autosomes, with the two Delta class GSTs and two Theta class GSTs clustered on a chromosome. AgosGSTCD3 is evolutionarily conserved in aphids, encoding 550 amino acids with the C-terminal region containing a methyltransferase domain. AgosGSTo4 exhibits alternative splicing, resulting in the formation of three isoforms. GSTs show conservation among Hap1, Hap3, and Hap4, except for AgosGSTm9, which demonstrates noticeable variations in the protein-coding regions and surrounding areas among the three haplotypes of A. gossypii. The expression profiles of GSTs were observed in the three haplotypes of A. gossypii, most showing different expression levels. These findings provide a valuable resource for further investigations into population differentiation and pesticide resistance evolution.