Abstract
Under global warming, the frequency and severity of agricultural pest outbreaks have intensified, posing serious threats to agriculture. The green peach aphid (Myzus persicae (Hemiptera: Aphididae)), an important agricultural pest, exhibits green and red color morphs and differentiated thermal tolerance, yet the underlying molecular mechanisms remain unclear. In this study, based on transcriptome and 16S rDNA amplicon sequencing, we analyzed the gene expression patterns and microbial community dynamics of green and red morphs of M. persicae under high-temperature stresses (30 °C and 35 °C) and across different exposure durations, comparing their similarities and differences in heat-response processes. Principal component analysis of transcriptomic data indicated that temperature had a greater influence on the physiological responses of M. persicae than body color, with a more pronounced effect observed at 35 °C. Differential gene expression analysis revealed overlap in temperature-responsive genes but different response patterns between the two morphs, suggesting activation of divergent molecular response mechanisms. Genes encoding heat shock proteins, detoxification-related enzymes, ribosomal protein family and so on were significantly up-regulated under high temperature, with a more pronounced induction in the green morph, indicating morph-specific regulatory strategies in response to thermal stress. Moreover, 16S rDNA sequencing revealed that the primary symbiont Buchnera displayed different relative abundance trends in the green and red morphs, remaining relatively stable in the red morph but declining markedly in the green morph under heat stress, potentially associated with their variation in thermal tolerance. Collectively, this study elucidates the molecular responses and microbe-mediated regulatory mechanisms underlying thermal tolerance in green and red morphs of M. persicae, providing novel insights into the thermal adaptation of aphids and a theoretical basis for developing pest management strategies under global warming.