INVESTIGATORS: C.J. Tsai, Scott A. Harding, Michael G. Hahn, Gary F. Peter, Shawn D. Mansfield
INSTITUTIONS: University of Georgia, University of Florida, University of British Columbia
NON-TECHNICAL SUMMARY: Tubulin proteins form microtubule scaffolds which participate in cell wall biogenesis. They are thought to regulate the deposition of cellulose, which constitutes ~50% of lignocellulosic biomass in woody feedstock species like Populus. Microtubule dynamics also regulate stomatal guard cell movements for photosynthesis and transpiration. The orchestration of these processes by tubulins; however, is poorly understood. We propose to investigate how various tubulin proteins and/or their modified forms affect cell wall properties in wood-forming tissues and stomatal movements in leaf guard cells. The work will ultimately allow us to dissect the contribution of tubulins to two inter-dependent processes, water utilization and the development of lignocellulosic biomass, that are relevant to bioenergy crop improvements.
OBJECTIVES: We seek to determine how transgenic manipulation of tubulin levels or tubulin protein modifications affects wood development and water use in Populus. The work will build on preliminary findings that perturbation of certain tubulins can alter wood physicochemical properties and leaf photosynthetic response to drought in Populus.
APPROACH: We will transgenically express various Populus alpha- and beta-tubulin genes, either individually or in combination, in a targeted, cell-specific manner (leaf guard cells and developing xylem). Both the native genes and the engineered forms that mimic post-translational modifications of tubulins will be tested. Two experimental treatments, tension wood induction and drought stress, will be applied to perturb wood formation and water relations, respectively, to facilitate the investigation. Gene and metabolite profiling, stress physiology, cell wall glycan composition, and wood physicochemical analyses will be carried out to produce a high-resolution description of the effects of tubulin manipulation on cell wall traits and drought stress response in Populus.
Name: C.J. Tsai