Institute of Entomology, Guizhou University, Guiyang, China; College of Life Science, Chongqing Normal University, Chongqing, China.
Institute of Entomology, Guizhou University, Guiyang, China; Scientific Observing and Experimental Station of Crop Pests in Guiyang, Ministry of Agriculture and Rural Affairs of the People's Republic of China, China; Guizhou Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Guiyang, China.
Pestic Biochem Physiol. 2021 Mar;173:104779. doi: 10.1016/j.pestbp.2021.104779. Epub 2021 Jan 19.
The isoprene branching pathway is a unique downstream synthesis pathway of juvenile hormone (JH) in arthropods, which plays an important role in the growth, development, and reproduction of insects. Juvenile hormone acid O-methyltransferase (JHAMT) and farnesoic acid O-methyltransferase (FAMeT) are two key proteins that are regulated in the isoprene branching pathway. Based on the available transcriptomic and genomic data of Sogatella furcifera, full-length cDNAs of SfJHAMT and SfFAMeT were identified. In vitro injection of dsRNA targeted to silence SfJHAMT and SfFAMeT inhibited the fecundity, ovarian development, and transcription levels of SfKr-h1 and SfVg significantly. Of note, The transcription levels of SfJHAMT and SfFAMeT are regulated mutually; i.e., silencing of SfJHAMT causes an increase in the SfFAMeT transcription level and vice versa, and the negative effect of simultaneous silencing on reproduction is greater. The results revealed a coordinated effect of SfJHAMT and SfFAMeT on the reproductive capabilities of S. furcifera. Furthermore, a JH analog (methoprene) partially rescued the negative effect of simultaneous silencing by SfJHAMT and SfFAMeT on reproduction. In addition, the expression profile analysis after insecticide stress showed that triazophos (LC) can induce the transcription of SfMet and SfKr-h1 to promote JH signal transduction, which affects the transcription of SfVg and ultimately promotes the reproduction of S. furcifera. The results of the present study lay a foundation to further explain the isoprene branch pathway function in insect reproduction and can open up new avenues for sustainable pest control while expanding the current understanding of molecular mechanisms through which insecticides stimulate reproduction and lead to pest resurgence.
异戊二烯支链途径是节肢动物中保幼激素（JH）的独特下游合成途径，在昆虫的生长、发育和繁殖中起着重要作用。保幼激素酸 O-甲基转移酶（JHAMT）和法呢酸 O-甲基转移酶（FAMeT）是异戊二烯支链途径中受调控的两个关键蛋白。基于褐飞虱的转录组和基因组数据，鉴定了 SfJHAMT 和 SfFAMeT 的全长 cDNA。体外注射靶向沉默 SfJHAMT 和 SfFAMeT 的 dsRNA 显著抑制了褐飞虱的繁殖力、卵巢发育和 SfKr-h1 和 SfVg 的转录水平。值得注意的是，SfJHAMT 和 SfFAMeT 的转录水平相互调节；即沉默 SfJHAMT 会导致 SfFAMeT 的转录水平增加，反之亦然，同时沉默对繁殖的负面影响更大。结果表明 SfJHAMT 和 SfFAMeT 对褐飞虱的繁殖能力有协同作用。此外，JH 类似物（灭幼脲）部分挽救了 SfJHAMT 和 SfFAMeT 同时沉默对繁殖的负面影响。此外，杀虫剂胁迫后的表达谱分析表明，三唑磷（LC）可以诱导 SfMet 和 SfKr-h1 的转录，以促进 JH 信号转导，从而影响 SfVg 的转录，最终促进褐飞虱的繁殖。本研究的结果为进一步解释异戊二烯支链途径在昆虫繁殖中的功能奠定了基础，并为可持续害虫控制开辟了新途径，同时扩展了目前对杀虫剂刺激繁殖和导致害虫再次出现的分子机制的理解。
