FERULATES IN FORAGE GRASS CELL WALLS - THEIR SIGNIFICANCE FOR CELL WALL GROWTH AND DIGESTIBILITY

The accumulation of ferulates and the cross- linking of Arabinoxylans via diferulate esters in the leaves of grasses are hypothesized to function in cell wall extensibility, cell elongation, nucleation of lignin polymerization, wall susceptibility to hydrolytic enzymes, and resistance to pests. To tests the hypothesized roles of ferulic acid in the cell wall, we have assembled an interdisciplinary research team with expertise on xylan feruloylation, wall mechanics, wall breakdown, and plant-insect interactions. We showed previously that expression of a fungal ferulic acid esterase gene in a grass (fescue) resulted in substantial reduction in cell-wall esterified ferulates and diferulates. We propose a series of more direct experiments to investigate the fundamental roles of cell wall feruoylation, making use of these transgenic plants. Our results will give the most direct and detailed test of the notion that of the hypothesized roles of cell wall ferulic cross- linking for control of plant growth, response of walls to wall-loosening enzymes, nucleation of lignin, degradability of walls by microbial and endogenous enzymes, and resistance to insect pests. Thus, in addition to provide basic knowledge about biochemical process and interactions in grasses, which are the mainstay of agricultural productivity and thus, this research may also provide key insights for the development of crop varieties with higher yields and improved qualities, particularly for sustainable production of bioenergy,animal nutrition and pest resistance as well as for cereals grains for human and animal consumption.