We are applying our expertise in insect nutritional physiology and bacterial symbiosis to identify and validate novel molecular targets for insect pest control. Plant sap feeding insects, including aphids and whiteflies, are increasingly important crop pests because they transmit plant viruses and can develop super-abundant populations, especially under no/low-insecticide regimes (e.g. organic crop production, Bt-crops resistant to chewing insect pests).
A major focus of our research is the osmotic challenge faced by insects feeding on sugar-rich phloem sap. We have shown that sugar transformations and water cycling in the gut of these insects play a central role in osmoregulation: knock-down of the molecular functions underpinning osmoregulation by chemical inhibitors or RNAi causes the insects to dehydrate and die.
We are currently investigating the genes mediating sugar transformations in multiple phloem feeding insects, with particular emphasis on whiteflies. Our ongoing research is indicating that the molecular basis of this common physiological function is conserved among the different insects .
In parallel, we are pursuing strategies to improve the efficacy of RNAi for phloem-feeding insects, both against known molecular targets and as a tool to validate other candidate targets. Specifically, we are working to identify suppressors of RNAi that we can target for improved RNAi against essential genes.
We are working with colleagues, as part of the NSF Research Coordination Network on Insect Genetic Technologies (IGTRCN) coordinated by Dr Dave O’Brochta, to develop genetic resources for hemipteran insects. We have also contributed to the analysis of the whitefly Bemisia tabaci genome, with publication in late 2016.
Selected Recent Publications
Luo Y, Chen Q, Luan J, Chung S-H, Van Eck J, Turgeon ER and Douglas AE, 2017. Towards an understanding of the molecular basis of effective RNAi against a global insect pest, the whitefly Bemisia tabaci. Insect Biochemistry and Molecular Biology 88: 21-29.
Douglas AE, 2017. Strategies for enhanced crop resistance to insect pests. Annual Review of Plant Biology. Epub 16 Nov
Arora AK and Douglas AE, 2017. Hype or opportunity? Using microbial symbionts in novel strategies for insect pest control. Journal of Insect Physiology 103: 10-17.
Chen W, Hasegawa DK, Kaur N, Kliot A, Pinheiro P, Luan J, Stensmyr MC, Zheng Y, Liu W, Sun H, Xu Y, Luo Y, Kruse A, Yang X, Kontsedalov S, Lebedev G, Fisher TW, Nelson DR, Hunter WB, Brown JK, Jander G, Cilia M, Douglas AE, Ghanim M, Simmons AV, Wintermantel WM, Ling K-S and Fei Z 2016. The draft genome of whitefly Bemisia tabaci MEAM1, a global crop pest, provides novel insights into virus transmission, host 5 adaptation, and insecticide resistance. BMC Biology 14, 110.
Jing XF, White TA, Luan J, Jiao C, Fei Z and Douglas AE, 2016. Evolutionary conservation of candidate osmoregulation genes in plant phloem-sap feeding insects. Insect Molecular Biology 25, 251-8.
For financial support of our research, we thank:
OPP1058938: Bill and Melinda Gates Foundation African cassava whitefly: outbreak causes and sustainable solutions (current) This consortium grant is led by PI John Colvin, Natural Resources Institute, London; full details of the consortium are available here)
NIFA Grant GRANT12216941. Enhancing the efficacy of in planta RNAi against phloem-feeding insects (with coPI Bob Turgeon) (current)