Location: Hard Winter Wheat Genetics ResearchTitle: Rapid mobilization of membrane lipids in wheat leaf-sheathes during incompatible interactions with hessian fly Author
Submitted to: Plant Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2012
Publication Date: 7/1/2012
Publication URL: http://apsjournals.apsnet.org/doi/abs/10.1094/MPMI-01-12-0022-R
Citation: Zhu, L., Liu, X., Wang, H., Khajuria, C., Reese, J.C., Whitworth, J.R., Welti, R., Chen, M. 2012. Rapid mobilization of membrane lipids in wheat leaf-sheathes during incompatible interactions with hessian fly. Plant Journal. 25 (7):920-930. Interpretive Summary: Host plant resistance is the most effective way to control Hessian fly (HF), an important pest of wheat. However, resistance in current wheat cultivars is short-lived, usually lasting for only 6-8 years. To develop more durable resistant wheat varieties, we need a better understanding of the resistance mechanisms at the molecular level. In this study, we discovered that there was rapid mobilization of membrane lipids in resistant plants following HF attack. The mobilized membrane lipids were likely converted into defense-related products such as polyunsaturated free fatty acids, oxylipins, and components of cuticle wax. Our results suggest that rapid mobilization of membrane lipids may constitute an important step in wheat defense against HF attack. This research provides a foundation for future research on the role of lipids in wheat resistance to HF, which may lead to practical application in resistant wheat breeding.
Technical Abstract: Hessian fly (Mayetiola destructor) is a biotrophic parasitic insect that interacts with wheat on a typical gene-for-gene basis. In this study, we systematically profiled changes in membrane lipids in two isogenic wheat lines: a susceptible line and its backcrossed offspring containing resistance gene H13. Our results revealed a 32 to 45% reduction in total concentration of 129 detected lipid species in resistant plants during incompatible interactions within the first 24 hrs after the initial attack. No significant change was observed in lipid concentration in susceptible plants during compatible interactions. Microarray and quantitative PCR analyses of 168 lipid-metabolism related transcripts, including those encoding various lipases, lipid transfer proteins, enzymes involved in oxylipin synthesis, and enzymes involved in wax and cutin synthesis, revealed that the levels of many of these transcripts increased rapidly in resistant plants after Hessian fly attack, but did not change in susceptible plants. Collectively, our data, along with previously published results, indicate that the mobilized lipids were converted through lipolysis into fatty acids, which were further converted into defense-signaling molecules including oxylipins and direct-defense molecules such as components of cuticle wax. Our results suggest that rapid mobilization of membrane lipids constitutes an important step in wheat defense against Hessian fly.