Supplementary Information - Chapter 2. Metabarcoding and genomic analysis of two insecticide-degrading bacteria in E. heros (Hemiptera: Pentatomidae) led to the identification of a new insect-associated Serratia species

The microbiota plays a diverse role in their hosts life, contributing to various adaptation and defense processes, such as the degradation of pesticides. It is now also known that the associated microbiota suffers the same selection pressure as the host. For this reason, this study aimed to investigate the influence of the evolution of E. heros resistance to thiamethoxam and lambda-cyhalothrin on the diversity of the gut microbiota, as well as to identify and characterize insecticide-degrading bacteria using comparative genomics strategies.  We compared the gut microbiota composition of the gut of susceptible and insecticide-resistant strains of E. heros, as well as the gut microbiota from E. heros field-collected adults. The experiments were conducted through metagenomic analysis of the V4 regions of the 16S ribosomal gene (16S rRNA). The gut microbiota analysis of E. heros revealed a strong predominance of the phylum Pseudomonadota, specifically the class Gammaproteobacteria, which plays a key role in the insect gut environment. The most abundant genera were from the Enterobacteriaceae and Erwiniaceae families, including Pantoea, Yokenella, Erwinia and Serratia. A higher microbial diversity was found in laboratory strains compared to field populations, a surprising result. Pyrethroid-resistant strains (RESPYR) showed a greater abundance of Serratia, Siccibacter and Pantoea, and the Serratia and Siccibacter was also identified as potential biomarkers for pyrethroid-resistant strains. Through comparative genomic analyses, two insecticide-degrading bacteria was identified in E. heros, a new specie: Serratia toxivorans n. sp., and Delftia acidovorans. Our results emphasize the importance of the microbiota in metabolizing toxic compounds, and that the associated microbiota as well as the host are under selection pressure.