Identification, expression profiling and potential functional roles of nuclear receptors in the social aphid Pseudoregma bambucicola.

Background: Nuclear receptors (NRs) constitute a superfamily of transcription factors that regulate diverse biological processes. In insects, NRs not only govern essential physiological functions including metabolism, development, and reproduction, but also play pivotal roles in regulating caste differentiation and division of labor within social insect colonies. Pseudoregma bambucicola is a species of social aphid in which adults exhibit a specialized reproductive division of labor. This unique system produces first-instar nymphs and soldiers, which share an identical genetic background yet exhibit distinct morphological and behavioral traits. Although NRs exhibit pleiotropic regulatory capacities, their roles in the unique developmental patterns of P. bambucicola remain unclear.

Results: This study identified 21 NR genes based on the genomic data of P. bambucicola and analyzed the duplication and loss events of these genes through phylogenetic analysis. Additionally, differential expression of NR genes was analyzed using transcriptomic data. The TLL exhibited significant differential expression in adults with distinct reproductive behaviors, suggesting its involvement in the regulation of reproductive division of labor. E75 and HNF4 were found to be important for the post-embryonic development of soldiers. Furthermore, quantitative real-time PCR confirmed caste-specific expression patterns of HR4 and HR39, indicating their potential involvement in morphological differentiation and developmental regulation among castes.

Conclusions: This study conducted bioinformatic identification of NR genes in the social aphid P. bambucicola, and investigated their potential roles in morphological differentiation and behavioral division through analysis of differential gene expression. The findings provide preliminary evidence for the functional significance of NR genes in social aphids, while offering novel insights for subsequent research exploration.