Transcriptomic insights on impaired survival and enhanced pesticide susceptibility following knockdown of Syntaxin5...

Membrane fusion, essential for a variety of biological processes, is ubiquitous and critical in all living organisms. The soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) comprise the core machinery that mediates membrane fusion. Syntaxin5 (Stx5) in mammals and its ortholog Sed5p in yeast are SNARE proteins that have been reported to mediate anterograde and retrograde endoplasmic reticulum (ER)-Golgi trafficking. In this study, a syntaxin5 gene (Lmsyx5) was cloned from the migratory locust, Locusta migratoria, and its tissue expression pattern showed widespread expression in different tissues. Knockdown of this gene using RNA interference (RNAi) revealed that both 5^th instars and adult locusts have reduced survival, and almost all of the 5^th instar locusts died before molting. Transcriptomic analysis revealed that drug or xenobiotic metabolism-related pathways are the most significantly downregulated in the central nervous system (CNS) of the RNAi 5^th instar locusts, whereas amino acid metabolism-related pathways are significantly downregulated in the muscle. In addition, receptor interaction-related pathways are downregulated in both the CNS and muscle. The mortality rate was significantly higher when dsLmsyx5 and beta-cypermethrin were combined together than when RNAi and chemical pesticides were used alone. Taken together, the Lmsyx5 gene is essential for locust survival, affects locust molting, is involved in the metabolism of both xenobiotics and endogenous chemicals in various tissues, and regulates locust susceptibility to chemical pesticides. It can thus be a potential target for locust control, and its knockdown using RNAi has great potential when combined with chemical pesticides.