Fu Jinqiu, Xu Shijing, Lu Huan, Li Fanchi, Li Shengchun, Chang Ling, Heckel David G, Bock Ralph, Zhang Jiang
State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China.
Department of Entomology, Max-Planck-Institut für Chemische Ökologie, Jena, Germany.
Plant Cell Environ. 2022 Jun;45(6):1930-1941. doi: 10.1111/pce.14314. Epub 2022 Apr 5.
Plant-mediated RNA interference (RNAi) has emerged as a promising technology for pest control through expression of double-stranded RNAs (dsRNAs) targeted against essential insect genes. However, little is known about the underlying molecular mechanisms and whether long dsRNA or short interfering RNAs (siRNAs) are the effective triggers of the RNAi response. Here we generated transplastomic and nuclear transgenic tobacco plants expressing dsRNA against the Helicoverpa armigera ATPaseH gene. We showed that expression of long dsRNA of HaATPaseH was at least three orders of magnitude higher in transplastomic plants than in transgenic plants. HaATPaseH-derived siRNAs are absent from transplastomic plants, while they are abundant in transgenic plants. Feeding transgenic plants to H. armigera larvae reduced gene expression of HaATPaseH and delayed growth. Surprisingly, no effect of transplastomic plants on insect growth was observed, despite efficient dsRNA expression in plastids. Furthermore, we found that dsRNA ingested by H. armigera feeding on transplastomic plants was rapidly degraded in the intestinal fluid. In contrast, siRNAs are relatively stable in the digestive system. These results suggest that plant-derived siRNAs may be more effective triggers of RNAi in Lepidoptera than dsRNAs, which will aid the optimization of the strategies for plant-mediated RNAi to pest control.
植物介导的RNA干扰（RNAi）已成为一种很有前景的害虫防治技术，通过表达针对昆虫必需基因的双链RNA（dsRNA）来实现。然而，对于其潜在的分子机制以及长dsRNA还是短干扰RNA（siRNA）是RNAi反应的有效触发因素，我们了解得还很少。在此，我们构建了表达针对棉铃虫ATPaseH基因dsRNA的转质体和核转基因烟草植株。我们发现，在转质体植株中，HaATPaseH长dsRNA的表达量比转基因植株中至少高三个数量级。转质体植株中不存在源自HaATPaseH的siRNA，而在转基因植株中它们却大量存在。用转基因植株喂养棉铃虫幼虫会降低HaATPaseH的基因表达并延缓其生长。令人惊讶的是，尽管质体中dsRNA表达高效，但未观察到转质体植株对昆虫生长有影响。此外，我们发现，取食转质体植株的棉铃虫摄取的dsRNA在肠液中会迅速降解。相比之下，siRNA在消化系统中相对稳定。这些结果表明，植物来源的siRNA可能比dsRNA更有效地触发鳞翅目昆虫的RNAi反应，这将有助于优化植物介导的RNAi害虫防治策略。
