Amenability of (Lepidoptera: Crambidae) to gene silencing through exogenous administration and host-delivered dsRNA in pigeonpea ( L.).

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Insect pests are one of the major biotic stresses limiting yield in commercially important crops. The lepidopteran polyphagous spotted pod borer, causes significant economic losses in legumes including pigeonpea. RNA interference (RNAi)-based gene silencing has emerged as one of the potential biotechnological tools for crop improvement. We report in this paper, RNAi in through exogenous administration of dsRNA with sequence specificity to three functionally important genes, Alpha-amylase (), Chymotrypsin-like serine protease () and Tropomyosin () into the larval haemolymph and their host-delivered RNAi in pigeonpea. Significant decline in the expression of selected genes supported by over-expression of and generation of siRNA indicated the occurrence of RNAi in the dsRNA-injected larvae. Additionally, the onset of RNAi in the herbivore was demonstrated in pigeonpea, one of the prominent hosts, by host-delivered dsRNA. Transgenics in pigeonpea (cv. Pusa 992), a highly recalcitrant crop, were developed through a shoot apical meristem-targeted transformation strategy and evaluated. Plant level bioassays in transgenic events characterized and selected at molecular level showed mortality of . larvae as well as reduced feeding when compared to wild-type. Furthermore, molecular evidence for down regulation of target genes in the insects that fed on transgenic plants authenticated RNAi. Considering the variability of gene silencing in lepidopteran pests, this study provided corroborative proof for the possibility of gene silencing in through both the strategies.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-022-01133-3.