Genome-wide identification and expression profile analysis of the Ras superfamily genes in eastern honeybee (Apis cerana)

The Ras superfamily, a crucial gene family in eukaryotes, functions as molecular switches that regulate various physiological and biochemical processes within cells. However, research on this topic remains limited concerning Apis cerana, a pollinator of significant economic and ecological importance. Here, 83 Ras superfamily genes in the genome of A. cerana were identified and classified into five distinct families. Phylogenetic analysis revealed that the homologous genes from two closely related species, A. cerana and Apis mellifera, clustered with relatively high bootstrap values. Notably, Rerg was unique to A. cerana compared to A. mellifera and had undergone gene duplication events. Expression profiles indicated diverse expression patterns of the Ras superfamily in the fat body during the holometabolous development of A. cerana. Most genes exhibited high expression levels during the later stages of adipose tissue remodeling; however, a minority were predominantly expressed during the prepupal (PP) and 1-day-old pupae (P1) stages. Among the 8 pairs of genes that had undergone gene duplication, 4 had inconsistent patterns, and 3 pairs were from the Ras family. In particular, Di-Ras2-2 was found to be highly expressed exclusively at the PP, and Rap2a-2 was only highly expressed during newly emerged (Em) stage. The observed differences in expression patterns may reflect adaptations to varying energy metabolism modes or environmental pressures. These findings provided a foundational basis for further investigation into the potential physiological roles of the Ras superfamily in A. cerana and offered valuable insights for analyzing this gene family across other insect species.