Department of Biosciences, Durham University, Durham DH1 3LE, UK.
Int J Mol Sci. 2018 Apr 4;19(4):1079. doi: 10.3390/ijms19041079.
RNA interference (RNAi) effects in insects are highly variable and may be largely dependent upon the stability of introduced double-stranded RNAs to digestion by nucleases. Here, we report a systematic comparison of RNAi effects in susceptible red flour beetle () and recalcitrant pea aphid () following delivery of dsRNAs of identical length targeting expression of V-type ATPase subunit E () and inhibitor of apoptosis () genes. Injection and ingestion of and dsRNAs resulted in up to 100% mortality of larvae and sustained suppression (>80%) of transcript levels. In , injection of but not dsRNA resulted in up to 65% mortality and transient suppression (ca. 40%) of transcript levels. Feeding aphids on dsRNA reduced growth and fecundity although no evidence for gene suppression was obtained. Rapid degradation of dsRNAs by aphid salivary, haemolymph and gut nucleases contrasted with stability in larvae where it appears that exo-nuclease activity is responsible for relatively slow digestion of dsRNAs. This is the first study to directly compare RNAi effects and dsRNA stability in receptive and refractory insect species and provides further evidence that dsRNA susceptibility to nucleases is a key factor in determining RNAi efficiency.
RNA 干扰 (RNAi) 在昆虫中的效果差异很大，可能在很大程度上取决于引入的双链 RNA 对核酸酶消化的稳定性。在这里，我们报告了在易感性红粉甲虫（）和抗性豌豆蚜（）中，用靶向 V 型 ATP 酶亚基 E（）和凋亡抑制剂（）基因表达的相同长度的 dsRNA 进行 RNAi 处理后的效果的系统比较。注射和摄入 和 dsRNA 导致 幼虫的死亡率高达 100%，并持续抑制（>80%）转录水平。在 中，注射 dsRNA 但不是 dsRNA 导致高达 65%的死亡率和 转录水平的短暂抑制（约 40%）。尽管没有获得基因抑制的证据，但蚜虫在 dsRNA 上取食会降低生长和繁殖力。dsRNA 被蚜虫唾液、血淋巴和肠道核酸酶快速降解，而在 幼虫中则稳定存在，这表明外切核酸酶活性负责 dsRNA 的相对缓慢消化。这是首次直接比较易感性和抗性昆虫物种的 RNAi 效果和 dsRNA 稳定性的研究，进一步证明了 dsRNA 对核酸酶的敏感性是决定 RNAi 效率的关键因素。
