Department of Entomology, Cornell University, Ithaca, NY 14850, USA.
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
Genes (Basel). 2021 Mar 12;12(3):407. doi: 10.3390/genes12030407.
Insect pest control by RNA interference (RNAi)-mediated gene expression knockdown can be undermined by many factors, including small sequence differences between double-stranded RNA (dsRNA) and the target gene. It can also be compromised by effects that are independent of the dsRNA sequence on non-target organisms (known as sequence-non-specific effects). This study investigated the species-specificity of RNAi in plant sap-feeding hemipteran pests. We first demonstrated sequence-non-specific suppression of aphid feeding by dsRNA at dietary concentrations ≥0.5 µg µL. Then we quantified the expression of (nuclease) genes in insects administered homologous dsRNA (with perfect sequence identity to the target species) or heterologous dsRNA (generated against a related gene of non-identical sequence in a different insect species). For the aphids and , significantly reduced expression was obtained with the homologous but not heterologous dsRNA at 0.2 µg µL, despite high ds sequence identity. Follow-up experiments demonstrated significantly reduced expression of genes in the whitefly and mealybug administered homologous , but not heterologous aphid dss. Our demonstration of inefficient expression knockdown by heterologous dsRNA in these insects suggests that maximal dsRNA sequence identity is required for RNAi targeting of related pest species, and that heterologous dsRNAs at appropriate concentrations may not be a major risk to non-target sap-feeding hemipterans.
RNA 干扰（RNAi）介导的基因表达敲低可以通过许多因素来控制昆虫害虫的防治，包括双链 RNA（dsRNA）和靶基因之间的小序列差异。它也可能受到与 dsRNA 序列无关的非靶标生物的影响（称为序列非特异性效应）。本研究调查了植物刺吸式半翅目害虫中 RNAi 的物种特异性。我们首先证明了 dsRNA 在饮食浓度≥0.5μgµL 时对蚜虫取食的非特异性抑制作用。然后，我们量化了同源 dsRNA（与目标物种具有完全序列同一性）或异源 dsRNA（针对不同昆虫物种中具有不同序列的相关基因产生）处理后昆虫中（核酸酶）基因的表达。对于蚜虫 和 ，尽管 ds 序列高度一致，但在 0.2µgµL 时，同源 dsRNA 而不是异源 dsRNA 可显著降低 的表达。后续实验表明，同源 的但不是异源的蚜虫 dss 可显著降低烟粉虱 和粉虱 中 的 基因表达。我们在这些昆虫中证明了异源 dsRNA 表达敲低效率低下，这表明相关害虫物种的 RNAi 靶向需要最大的 dsRNA 序列同一性，并且适当浓度的异源 dsRNA 可能不会对非靶标刺吸式半翅目昆虫构成重大风险。
