Identification of the gustatory receptor gene family of Tuta absoluta and its expression analysis at different developmental stages

Insect gustatory receptors are a crucial class of chemoreceptors that can detect external environmental stimuli and influence insect behaviors such as host selection, feeding, mating, and oviposition. This study focused on the invasive pest Tuta absoluta (Meyrick) that affected tomatoes. To elucidate the characteristics of the gustatory receptor (GR) gene family in T. absoluta and investigate the expression patterns of GR genes across different developmental stages, we employed bioinformatics approaches to identify, chromosomally locate, conduct phylogenetic analysis, and analyze age-stage expression profiles of the GR genes in T. absoluta. The results indicated that 62 GR genes of the T. absoluta moth were identified and distributed on 19 chromosomes. The length of the encoded protein sequence ranged from 318 to 2034 bp, with an average of 5 exon fragments and 1 to 7 transmembrane regions. Phylogenetic analysis revealed that the GR genes of the T. absoluta could be categorized into four distinct subfamilies: bitter taste receptors (35 genes), carbon dioxide receptors (1 gene), sugar receptors (5 genes), and Gr43a-like receptors (7 genes). The remaining genes have not been classified yet. Expression analysis across different developmental stages revealed that the GR genes of the T. absoluta exhibited significant variation in expression levels throughout its life cycle. The research results provided a solid foundation for further elucidating the functions of gustatory receptor genes in the T. absoluta and uncovering its co-evolutionary relationship with host plants. These findings offered scientific evidence for controlling the T. absoluta by functional plants and lay the foundation for developing novel pest control technologies from a gustatory receptor perspective.