Supplementary Information - Chapter 1. Transcriptomic investigation of the molecular mechanisms underlying resistance to the neonicotinoid thiamethoxam and the pyrethroid lambda-cyhalothrin in Euschistus heros (Hemiptera: Pentatomidae)

Laboratory-selected resistant strains of Euschistus heros to thiamethoxam (NEO) and lambda-cyhalothrin (PYR) were recently reported in Brazil. However, the mechanisms conferring resistance to these insecticides in E. heros remain unresolved. We utilized comparative transcriptome profiling and single nucleotide polymorphism (SNP) calling of susceptible and resistant strains of E. heros to investigate the molecular mechanism(s) underlying resistance. The E. heros transcriptome was assembled, generating 91 673 transcripts with a mean length of 720 bp and N50 of 1795 bp. Comparative gene expression analysis between the susceptible (SUS) and NEO strains identified 215 significantly differentially expressed (DE) transcripts. DE transcripts associated with the xenobiotic metabolism were all up-regulated in the NEO strain. The comparative analysis of the SUS and PYR strains identified 204 DE transcripts, including an esterase (esterase FE4), a glutathione-S-transferase, an ABC transporter (ABCC1) and aquaporins that were up-regulated in the PYR strain. We identified 9588 and 15 043 nonsynonymous SNPs in the PYR and NEO strains. One of the SNPs (D70N) detected in the NEO strain occurs in a subunit (α5) of the nAChRs, the target site of neonicotinoid insecticides. Nevertheless, this residue position in α5 is not conserved among insects. Neonicotinoid and pyrethroid resistance in laboratory-selected E. heros is associated with a potential metabolic resistance mechanism by the overexpression of proteins commonly involved in the three phases of xenobiotic metabolism. Together these findings provide insight into the potential basis of resistance in E. heros and will inform the development and implementation of resistance management strategies against this important pest. *Published in: Pest Management Science 79.12 (2023): 5349-5361. https://doi.org/10.1002/ps.7745巴西近期有研究报道了经实验室筛选的赫氏蝽（Euschistus heros）对噻虫嗪（thiamethoxam, NEO）与氯氟氰菊酯（lambda-cyhalothrin, PYR）的抗性品系。但目前学界仍未阐明赫氏蝽对这两类杀虫剂产生抗性的分子机制。 本研究通过对赫氏蝽敏感品系与抗性品系开展比较转录组分析与单核苷酸多态性（single nucleotide polymorphism, SNP）检测，以探究其抗性背后的分子机制。 本研究组装得到赫氏蝽转录组，共获得91673条转录本，平均长度为720 bp，N50值为1795 bp。 对敏感品系（SUS）与NEO抗性品系的比较基因表达分析显示，二者存在215个显著差异表达（differentially expressed, DE）转录本；其中与外源物质代谢（xenobiotic metabolism）相关的差异表达转录本在NEO抗性品系中均呈上调表达。 对敏感品系与PYR抗性品系的比较分析则鉴定出204个差异表达转录本，包括在PYR抗性品系中上调表达的酯酶（esterase FE4）、谷胱甘肽S-转移酶（glutathione-S-transferase）、ABC转运蛋白（ABCC1）与水通道蛋白（aquaporins）。 本研究分别在PYR与NEO抗性品系中鉴定出9588和15043个非同义单核苷酸多态性。在NEO抗性品系中检测到的一处SNP位点（D70N）位于新烟碱类杀虫剂的作用靶标——烟碱型乙酰胆碱受体（nicotinic acetylcholine receptors, nAChRs）的α5亚基上，但该α5亚基的该残基位点在昆虫中并不保守。 经实验室筛选的赫氏蝽对新烟碱类与拟除虫菊酯的抗性，可能与外源物质代谢三个阶段相关蛋白的过表达所介导的代谢抗性机制有关。 本研究结果为解析赫氏蝽的抗性潜在机制提供了新见解，也将为针对这一重要害虫的抗性治理策略的制定与实施提供参考。 *本研究发表于《Pest Management Science》2023年第79卷第12期，页码为5349-5361，DOI：https://doi.org/10.1002/ps.7745