Objective:
This basic research is to determine the extent of compositional and structural changes in lignins of plants that have been genetically altered through manipulation of the lignin biosynthetic pathway. Proposed work will involve chemical & biochemical characterization of in situ & extracted lignins obtained from cell walls of plants that have one or more genetically modified enzymes in the lignin pathway. This information will lead to the development of strategies to improve utilization of plant cell walls for a wide range of commercial applications, including chemical pulping & digestibility of forages. Additional time will be used to complete final objectives on transgenics, and to submit at least two more manuscripts.

Approach:
We intend to: a) identify molecular markers for enzyme deficiencies & elucidate their structures & origins; b) continue to identify structural changes in transgenics with single and multiple gene manipulations for key enzymes (CAD, COMT, F5H, CCR, CCoAOMT, 4CL, C3H); c) develop new analytical methods for analyzing lignin structural changes & new synthetic methods to identify novel structures in lignins; d) determine effects of gene down- and up-regulation on pulping processes & on fiber digestibility; and e) produce plants that extend limits of metabolic plasticity, and to analyze those plants.