Assessment on effects of transplastomic potato plants expressing Colorado potato beetle β-Actin double-stranded RNAs for three non-target pests

RNA interference has been proved as an efficient technology for pest control through the silencing of essential genes of targeted insects. We had previously shown that the expression of double-stranded RNAs (dsRNAs) in plastids of plants offers a great potential for efficiently controlling Colorado potato beetle (CPB, Leptinotarsa decemlineata) (Coleoptera, Chrysomelidae). However, whether these transplastomic plants have an impact on other non-target pests was not investigated. In this study, we evaluated the potential effects of transplastomic plants expression dsRNAs target CPB beta-Actin (referred to as ACT plants) on three other potato pests: Myzus persicae (Hemiptera, Aphididae), Henosepilachna vigintioctopunctata (Coleoptera, Coccinellidae), and Spodoptera litura (Lepidoptera, Noctuidae). Although no effects on M. persicae or S. litura were observed by feeding ACT plants, we found that feeding H. vigintioctopunctata with ACT plants can result in its growth retardation and suppressing the gene expression of HvACT, which has 91.7% identity to CPB beta-Actin and shared 66 potential 21mer matches. Taking together, these results indicated that ACT plants had cross-resistance to H. vigintioctopunctata, another coleopteran insect with the highly conserved nucleotide sequence of beta-Actin gene. It also provided an opportunity to simultaneously control L. decemlineata and H. vigintioctopunctata by RNAi induced by intermediate dsRNAs with optimized sequences.

Automated summary

RNA interference is a efficient technology for pest control, and expression of dsRNAs in transplastomic plants may have potential effects on non-target pests. The study showed that ACT plants had cross-resistance to another coleopteran insect with highly conserved nucleotide sequence, providing an opportunity for simultaneous control of different pests.