Submitted to: Journal of Insect Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2007
Publication Date: 1/1/2008
Citation: Shukle, R.H., Yoshiyama, M., Morton, P.K., Schemerhorn, B.J. 2007. Tissue and developmental expression of a gene from Hessian fly encoding an ABC-active-transporter protein during interactions with wheat. Journal of Insect Physiology. 55:146-154. Interpretive Summary: The Hessian fly is a destructive pest of wheat, and in the eastern soft-winter-wheat region of the United States it is the most important insect pest. Despite its importance as a pest of wheat, little is known about the way Hessian fly larvae interact with wheat while feeding and how they detoxify and excrete various harmful chemicals produced by the wheat plant. We are systematically analyzing genes expressed in Hessian fly larvae while they feed on susceptible and resistant wheat and have identified major digestive enzymes, detoxification/antioxidant enzymes, and immune defense proteins. In the present study, we have identified a gene from Hessian fly involved in actively excreting toxic substances encountered by Hessian fly larvae as they feed on wheat. The knowledge from our work on detoxification and excretion mechanisms employed by Hessian fly larvae while feeding on wheat provides a basis for understanding how the pest interacts with wheat plants. Scientists facing the challenge of devising innovative methods of pest control through genetic engineering and other contemporary approaches will benefit from this fundamental knowledge. The agricultural community (crop producers and commodity groups) will benefit from improved pest control that increases yield and quality without increasing costs.
Technical Abstract: We report on the transcriptional patterns of a putative white (w) gene encoding an ABC-transporter protein during development in Hessian fly, Mayetiola destructor. The deduced amino acid sequence for the Hessian fly white showed 77 to 74% similarities to white/ATP-binding-cassette proteins and 57 to52% similarities to scarlet/ATP-binding-cassette proteins from other Dipterans. Conserved ATP-binding motifs and transmembrane '-helix segments were identified in the Hessian fly white protein further supporting its function as an ABC-active-transporter similar to the Drosophila white protein. Spatial analysis of transcript levels for white in larval Hessian fly tissues by quantitative real-time PCR revealed the greatest level of transcript in the Malpighian tubules, while analysis of temporal expression during development revealed the highest transcript levels in late 2nd-and early 3rd-instar larvae. Analysis of transcript levels for white in Hessian fly larvae feeding on susceptible and resistant wheat showed greater levels of transcript in larvae feeding on resistant plants. We speculate the increased transcript level for white in larvae feeding on resistant wheat could be correlated with stress and increased Malpighian tubule activity associated with the metabolism and detoxification of toxic substrates generated either endogenously or encountered exogenously from the host plant.