Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
Pest Manag Sci. 2021 Jan;77(1):77-84. doi: 10.1002/ps.6017. Epub 2020 Aug 13.
The southern green stinkbug, Nezara viridula (Hemiptera: Pentatomidae), is an important emerging polyphagous pest infesting soybean in the United States, Brazil and Argentina. The indiscriminate use of synthetic insecticides to control stinkbugs has limited the effectiveness of current management strategies. Alternatively, RNA interference (RNAi) has emerged as a novel mode of action to control pests in an eco-friendly manner.
Here, we assessed the potential of RNAi technology by oral delivery of double-stranded RNA (dsRNA) for the control of N. viridula. Initially, ten candidate genes were tested by microinjection assay to select the best target genes for oral delivery. Seven genes resulted in more than 90% mortality after microinjection. To evaluate RNAi efficacy by oral delivery of dsRNA, five genes were tested by feeding the insects on gene-specific dsRNA mixed with an artificial diet. Significant mortality of 43% and 45% was observed after 14 days of treatment with dsαCop and dsvATPase A, respectively. To elucidate the lower RNAi efficacy via oral delivery of dsRNA, ex vivo dsRNA degradation in the saliva and the midgut juice was performed, which indicated that the reduced RNAi efficacy is accompanied by a rapid degradation of dsRNA by digestive secretions.
This study proves that RNAi can be triggered by orally delivered dsRNA in N. viridula and can be exploited to control this economically important pest. The reduced stability of dsRNA in saliva and midgut that was observed indicates a need to further improve RNAi efficacy, for example by use of specific formulations.
南方绿椿象（Nezara viridula）（半翅目：蝽科）是一种重要的新兴杂食性害虫，在美国、巴西和阿根廷均有侵害大豆。为控制椿象而不加区分地使用合成杀虫剂已降低了当前管理策略的效果。相反，RNA 干扰（RNAi）已成为一种以生态友好方式控制害虫的新型作用模式。
在这里，我们通过口服双链 RNA（dsRNA）评估了 RNAi 技术控制 N. viridula 的潜力。最初，通过微量注射试验测试了十个候选基因，以选择最适合口服递送的靶基因。微注射后，有 7 个基因导致死亡率超过 90%。为了通过口服 dsRNA 评估 RNAi 的功效，通过用基因特异性 dsRNA 与人工饲料混合喂养昆虫来测试五个基因。在用 dsαCop 和 dsvATPase A 处理 14 天后，分别观察到 43%和 45%的显著死亡率。为了阐明通过口服递送 dsRNA 降低 RNAi 功效的原因，在唾液和中肠液中进行了体外 dsRNA 降解实验，结果表明，RNAi 功效的降低伴随着消化液中 dsRNA 的快速降解。
本研究证明了 RNAi 可以通过口服递送的 dsRNA 在 N. viridula 中被触发，并可被用于控制这种具有重要经济意义的害虫。观察到的 dsRNA 在唾液和中肠中稳定性降低表明需要进一步提高 RNAi 功效，例如使用特定配方。
