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Molecular Analysis of Xenobiotic Response in the Colorado Potato Beetle
Department of Entomology
Colorado potato beetle (CPB) is a notorious pest. High fecundity, diverse and flexible life history and an ability to detoxify xenobiotics make this insect difficult to manage. The coevolution of this beetle with its host plants that contain toxic chemicals may have led to its remarkable xenobiotic resistance. This beetle has developed resistance to all classes of synthetic chemicals introduced for its control.
We recently completed pyrosequencing of CPB transcriptome, prepared custom microarray, and developed feeding RNAi methods. These recent developments prepared us to exploit this insect to study the mechanisms of plant chemical detoxification. We will employ CPB custom microarrays to identify detoxification enzymes induced by plant chemicals. The top 50 xenobiotic enzymes identified will be confirmed qRT-PCR. We will employ RNAi to study the function and mechanisms of plant chemical induction of 20 selected enzymes. We will determine the role of three nuclear receptors (HR96, HNF4 and USP) and four bHLH-PAS transcription factors (Tango, Spineless, SRC and Met) in plant chemical detoxification. We will determine the possibility of using identified genes in management of these beetles through RNAi pest management.
2011 Project Description
RNA interference (RNAi) is a breakthrough technology for conducting functional genomics studies and also as a potential tool for crop protection against insect pests. Themajor challenge for efficient pest control using RNAi in the field is the development of efficient and reliable methods for production and delivery of double-stranded RNA (dsRNA).
In this project, the potential of feeding dsRNA expressed in bacteria or synthesized in vitro to manage populations of Colorado potato beetle, Leptinotarsa decemlineata (Say) (CPB), was investigated. Feeding RNAi successfully triggered the silencing of all five target genes tested and caused significant mortality and reduced body weight gain in the treated beetles.
This study provides the first example of an effective RNAi response in insects after feeding dsRNA produced in bacteria. These results suggest that the efficient induction of RNAi using bacteria to deliver dsRNA is a possible method for management of CPB. This could be also a promising bioassay approach for genome-wide screens to identify effective target genes for use as novel RNAi-based insecticides.
A new method was developed for controlling Colorado potato beetle.
Zhu, F., Xu, J., Palli, R., Ferguson, J. & Palli, S. R. (2011) Ingested RNA interference for managing the populations of the Colorado potato beetle, Leptinotarsa decemlineata, Pest Manag Sci. 67, 175-82.107.