Transcriptomic and Metatranscriptomic Analyses Provide New Insights into the Response of the Pea Aphid Acyrthosiphon pisum (Hemiptera: Aphididae) to Acetamiprid.

Simple Summary: Acetamiprid, commonly used in agriculture to control aphids, faces the problem of resistance development in certain aphid species. To investigate the insect mechanisms involved in the adaptation process to acetamiprid, we compared the gene expression and microbial profiles of a pea aphid strain selected with acetamiprid (RS) with those of a non-selected strain (SS) using advanced omics techniques. The overall analysis revealed significant changes in the expression of genes involved in carbon and fatty acid metabolism in RS compared to those of SS aphids. In particular, we found increased expression of specific genes related to the synthesis of the components of the epidermal wax layer, suggesting that adaptation to acetamiprid involves the synthesis of a thicker protective layer. Additionally, subtle shifts in the bacterial composition of RS were detected. These results contribute valuable insights into the mechanisms underlying the pea aphid's response to acetamiprid exposure. Such understanding is essential for informing future research efforts and developing more effective strategies to control this pest. Acetamiprid is a broad-spectrum neonicotinoid insecticide used in agriculture to control aphids. While recent studies have documented resistance to acetamiprid in several aphid species, the underlying mechanisms are still not fully understood. In this study, we analyzed the transcriptome and metatranscriptome of a laboratory strain of the pea aphid, Acyrthosiphon pisum (Harris, 1776), with reduced susceptibility to acetamiprid after nine generations of exposure to identify candidate genes and the microbiome involved in the adaptation process. Sequencing of the transcriptome of both selected (RS) and non-selected (SS) strains allowed the identification of 14,858 genes and 4938 new transcripts. Most of the differentially expressed genes were associated with catalytic activities and metabolic pathways involving carbon and fatty acids. Specifically, alcohol-forming fatty acyl-CoA reductase (FAR) and acyl-CoA synthetase (ACSF2), both involved in the synthesis of epidermal wax layer components, were significantly upregulated in RS, suggesting that adaptation to acetamiprid involves the synthesis of a thicker protective layer. Metatranscriptomic analyses revealed subtle shifts in the microbiome of RS. These results contribute to a deeper understanding of acetamiprid adaptation by the pea aphid and provide new insights for aphid control strategies. [ABSTRACT FROM AUTHOR]