Department of Entomology, Cornell University, Ithaca, NY14853, USA.
Department of Entomology, Cornell University, Ithaca, NY14853, USA; Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY14853, USA.
Insect Biochem Mol Biol. 2020 Aug;123:103408. doi: 10.1016/j.ibmb.2020.103408. Epub 2020 May 22.
RNA interference (RNAi) plays a key role in insect defense against viruses and transposable elements, and it is being applied as an experimental tool and for insect pest control. However, RNAi efficiency is highly variable for some insects, notably the pea aphid Acyrthosiphon pisum. In this study, we used natural variation in RNAi susceptibility of pea aphids to identify genes that influence RNAi efficiency. Susceptibility to orally-delivered dsRNA against the gut aquaporin gene AQP1 (ds-AQP1) varied widely across a panel of 83 pea aphid genotypes, from zero to total mortality. Genome-wide association between aphid performance on ds-AQP1 supplemented diet and aphid genetic variants yielded 103 significantly associated single nucleotide polymorphisms (SNPs), including variants in 55 genes, at the 10 probability cut-off. When ds-AQP1 was co-administered with dsRNA against six candidate genes, aphid mortality was reduced for three (50%) genes: the orthologs of the Drosophila genes trachealess (CG42865), headcase (CG15532) and a gene coding a peritrophin-A domain (CG8192), indicating that these genes function to promote RNAi efficiency against AQP1 in the pea aphid. Aphid susceptibility (quantified as mortality) to ds-AQP1 was correlated with RNAi against a further gene, snakeskin with essential gut function unrelated to AQP1, for some but not all aphid genotypes tested, suggesting that the determinants of RNAi efficiency may be partly gene-specific. This study demonstrates high levels of natural variation in susceptibility to RNAi and demonstrates the value of harnessing this variation to identify genes influencing RNAi efficiency.
RNA 干扰 (RNAi) 在昆虫抵御病毒和转座元件的防御中起着关键作用，它被用作实验工具和昆虫防治。然而，对于某些昆虫来说，RNAi 的效率变化很大，特别是豌豆蚜 Acyrthosiphon pisum。在这项研究中，我们利用豌豆蚜对 RNAi 敏感性的自然变异来鉴定影响 RNAi 效率的基因。对肠道水通道蛋白基因 AQP1 的口服 dsRNA（ds-AQP1）的敏感性在 83 个豌豆蚜基因型的一个小组中差异很大，从零到完全死亡。ds-AQP1 补充饮食中蚜虫表现与蚜虫遗传变异之间的全基因组关联产生了 103 个显著相关的单核苷酸多态性（SNP），包括 55 个基因中的变异，在 10%的概率截止值。当 ds-AQP1 与针对六个候选基因的 dsRNA 共同给药时，三种（50%）基因的蚜虫死亡率降低：果蝇基因 trachealess（CG42865）、headcase（CG15532）和一个编码 Peritrophin-A 结构域的基因的同源物，表明这些基因在豌豆蚜中促进了针对 AQP1 的 RNAi 效率。ds-AQP1 对蚜虫的敏感性（以死亡率衡量）与 RNAi 对另一个基因的相关性，该基因与 AQP1 无关但对一些而不是所有测试的蚜虫基因型具有重要的肠道功能，这表明 RNAi 效率的决定因素可能部分是基因特异性的。这项研究表明，对 RNAi 的敏感性存在高水平的自然变异，并证明了利用这种变异来鉴定影响 RNAi 效率的基因的价值。
