Submitted to: Journal of Plant Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2005
Publication Date: 10/15/2005
Citation: Sardesai, N., Subramanyam, S., Nemacheck, J.A., Williams, C.E. 2005. Modulation of defense-response gene expression in wheat during Hessian fly larval feeding. Journal of Plant Interactions. 1(1):39-50. Interpretive Summary: Little is known about mechanisms that are involved in defending wheat against attack from insect pests. Expression of 20 defense response genes was monitored in wheat plants containing the H13 Hessian fly-resistance gene. A subset of the genes responded to Hessian fly attack, indicating that defense against this insect shares some similarities to defense against microbial pathogens. Scientists working on plant resistance to microbes, insects and nematodes will benefit from the information presented. This work is the first step in identifying genes and biochemical pathways that work together to protect plants from insects. Once the genes are fully characterized the information can be used to modify plants, by either breeding or molecular methods, for more durable resistance.
Technical Abstract: The expression of 20 wheat genes, similar in sequence to up-regulated dicot defense- and wound- response genes, was monitored during the first 5 days after Hessian fly larvae initiated feeding. A subset of these genes (PR-1, PR-2, lipoxygenase, PAL) responded as predicted with higher mRNA levels in plants involved in incompatible interactions. Other genes (MAP kinase, WCI-5, WIR-1) responded similarly in both compatible and incompatible interactions. Several defense- and wound- response genes failed to activate. Responsive genes were derived from three inter-related signaling pathways mediated by jasmonic acid, salicylic acid and active oxygen species. This response profile shares some characteristics with dicot mechanisms known to participate in defense against viruses, bacteria and fungi. However, the response of wheat to Hessian fly attack is unique enough to suggest that additional genes, currently unidentified, play major roles in resistance.