Transcriptome Analysis of the Brain and Gnathal Ganglion Reveals Feeding-Mediated Genes in Helicoverpa armigera Larvae

Despite the central role of the gustatory nervous system in regulating feeding behavior in the larvae of the major agricultural pest <i>Helicoverpa armigera</i>, the systemic molecular basis of this process is largely unknown. To investigate the molecular basis, we performed RNA-seq on dissected brains and gnathal ganglion (GNG) from fifth-instar larvae, revealing 944 differentially expressed genes (DEGs) that are potentially involved in feeding behaviors. Bioinformatic analyses revealed significant enrichment of these DEGs in pathways including "taste transduction", "neuroactive ligand-receptor interaction", and "feeding behavior". Furthermore, 41 candidate genes closely associated with feeding behaviors were screened, including neuropeptides, neuropeptide receptors, gustatory receptors, and feeding-mediated proteins. Phylogenetic analyses demonstrated that these key genes are evolutionarily conserved. Quantitative real-time PCR (qPCR) results confirmed that most of these candidate genes were significantly upregulated during the fifth instar stage, and their expression was further enhanced under starvation conditions (<i>p</i> < 0.05). Our study presents the first systemic feeding-mediated transcriptomic profile in the insect central nervous system and identifies key feeding-mediated genes in <i>H. armigera</i> larvae. These findings advance our understanding of the molecular basis of feeding in Lepidopteran pests and offer potential target genes for developing gustatory-based pest control strategies.