Targeting detoxification genes by phloem-mediated RNAi: A new approach for controlling phloem-feeding insect pests. (September 2018)

• Record Type: Journal Article
• Authors: Eakteiman, Galit; Moses-Koch, Rita; Moshitzky, Pnina; Mestre-Rincon, Natividad; Vassão, Daniel G.; Luck, Katrin; Sertchook, Rotem; Malka, Osnat; Morin, Shai
• Is Part Of: Insect biochemistry and molecular biology. Volume 100(2018)
• Page Start: 10
• Page End: 21
• Publication Date: 2018-09
• Subjects: Phloem-feeding insects -- Bemisia tabaci -- Glutathion S-Transferase -- Plant-mediated RNAi -- Glucosinolates -- Environmentally-friendly pest control; Insect biochemistry -- Periodicals; Insects -- Physiology -- Periodicals; Insects -- Molecular aspects -- Periodicals; Biochemistry -- Periodicals; Insectes -- Biochimie -- Périodiques; Insectes -- Composition -- Périodiques; Insectes -- Physiologie -- Périodiques; Insectes -- Aspect moléculaire -- Périodiques; Biochimie -- Périodiques; Biochemistry; Insect biochemistry; Insects -- Molecular aspects; Insects -- Physiology; Periodicals; 572.8157
• DOI: 10.1016/j.ibmb.2018.05.008
• Languages: English
• ISSNs: 0965-1748

Abstract

Abstract: Many phloem-feeding insects are considered severe pests of agriculture and are controlled mainly by chemical insecticides. Continued extensive use of these inputs is environmentally undesirable, and also leads to the development of insecticide resistance. Here, we used a plant-mediated RNA interference (RNAi) approach, to develop a new control strategy for phloem-feeding insects. The approach aims to silence "key" detoxification genes, involved in the insect's ability to neutralize defensive and toxic plant chemistry. We targeted a glutathione S-transferase (GST) gene, BtGSTs5, in the phloem-feeding whitefly Bemisia tabaci, a devastating global agricultural pest. We report three major findings. First, significant down regulation of the BtGSTs5 gene was obtained in the gut of B. tabaci when the insects were fed on Arabidopsis thaliana transgenic plants expressing dsRNA against BtGSTs5 under a phloem-specific promoter. This brings evidence that phloem-feeding insects can be efficiently targeted by plant-mediated RNAi. Second, in-silico and in-vitro analyses indicated that the BtGSTs5 enzyme can accept as substrates, hydrolyzed aliphatic- and indolic-glucosinolates, and produce their corresponding detoxified conjugates. Third, performance assays suggested that the BtGSTs5 gene silencing prolongs the developmental period of B. tabaci nymphs. Taken together, these findings suggest that BtGSTs5 is likely to play an important role in enabling B. tabaci to successfully feed on glucosinolate-producing plants. Targeting the gene by RNAi in Brassicaceae cropping systems, will likely not eliminate the pest populations from the fields but will significantly reduce their success over the growing season, support prominent activity of natural enemies, eventually allowing the establishment of stable and sustainable agroecosystem. Graphical abstract: Image 1 Highlights: Phloem-mediated RNAi, significantly downregulated the expression of a detoxification gene, BtGSTs5, in Bemisia tabaci. BtGSTs5 gene expression was down-regulated in the gut but not in other insect tissues. The BtGSTs5 enzyme accepts as substrates hydrolyzed glucosinolates and produces their corresponding detoxified conjugates. BtGSTs5 gene silencing prolonged the developmental period of B. tabaci nymphs. Targeting BtGSTs5 by plant-mediated RNAi can reduce the population size of B. tabaci in Brassicaceae cropping systems.