Department of Plant Medicals, Andong National University, Andong, South Korea.
Division of Crop Cultivation and Environment Research, Department of Central Area Crop Science, National Institute of Crop Science, Rural Development Administration, Suwon, South Korea.
Pest Manag Sci. 2020 Mar;76(3):1020-1030. doi: 10.1002/ps.5612. Epub 2019 Oct 25.
Insulin/insulin-like growth factor signaling (IIS) is known to mediate larval growth and adult reproduction in the legume pod borer, Maruca vitrata (Lepidoptera: Crambidae). Four IIS components (InR, FOXO, Akt, and TOR) play crucial roles in the IIS pathway.
RNA interference (RNAi) against any of these four IIS component genes was effective in suppressing each target mRNA level by either hemocoelic injection or oral administration using gene-specific double-stranded RNAs (dsRNAs). These RNAi treatments interfered with larval growth, leading to small pupae or significant larval mortality. For massive production of dsRNA, transformed bacteria expressing dsRNAs of these four IIS components were prepared with L4440 expression vector and HT115 strain of Escherichia coli. The transformed bacteria killed the larvae in a dose-dependent manner by feeding administration. An ultra-sonication pretreatment was performed to impair bacterial membrane and increase dsRNA release from the bacteria in insect intestine. This pretreatment increased the insecticidal activity of these recombinant bacteria. To further increase dsRNA toxicity, its mixture with Bacillus thuringiensis (Bt) was prepared and showed significant increase of Bt insecticidal activity in the laboratory. The bacterial mixture also showed a high control efficacy (83.3%) in an adzuki bean (Vigna angularis) field infested by M. vitrata. Furthermore, such a dsRNA effect was specific for M. vitrata, but not for non-target insects.
The bacteria expressing dsRNA specific to IIS components can be used to develop dsRNA insecticide. © 2019 Society of Chemical Industry.
胰岛素/胰岛素样生长因子信号（IIS）被认为介导豆荚螟幼虫生长和成虫繁殖（鳞翅目：螟蛾科）。四个 IIS 成分（InR、FOXO、Akt 和 TOR）在 IIS 途径中发挥关键作用。
针对这四个 IIS 成分基因中的任何一个进行 RNA 干扰（RNAi），通过血腔注射或口服使用基因特异性双链 RNA（dsRNA），都能有效地抑制每个靶标 mRNA 水平。这些 RNAi 处理干扰了幼虫生长，导致小蛹或显著的幼虫死亡率。为了大量生产 dsRNA，用 L4440 表达载体和大肠杆菌 HT115 菌株制备了表达这四个 IIS 成分 dsRNA 的转化细菌。通过喂食，这些转化细菌以剂量依赖的方式杀死幼虫。通过超声预处理破坏细菌膜并增加昆虫肠道中 dsRNA 的释放。这种预处理增加了这些重组细菌的杀虫活性。为了进一步提高 dsRNA 的毒性，将其与苏云金芽孢杆菌（Bt）混合，并在实验室中显著提高了 Bt 的杀虫活性。细菌混合物在赤豆（Vigna angularis）受豆荚螟侵害的田间也表现出 83.3%的高防治效果。此外，这种 dsRNA 效应对 M. vitrata 是特异的，但对非靶标昆虫没有影响。
表达 IIS 成分特异性 dsRNA 的细菌可用于开发 dsRNA 杀虫剂。© 2019 化学工业学会。
