Submitted to: Gordon Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2003
Publication Date: August 11, 2003
Citation: Grabber, J.H. 2003. Pivotal role of ferulates in cell wall cross-linking and lignin formation in grasses. In: Proceedings of the Gordon Research Conference, August 10-15, 2003, Meriden, New Hampshire. Poster #19. Technical Abstract: Studies with tall fescue leaf blades (Festuca arundinacea Schreb.) and maize cell suspensions (Zea mays L.) are revealing the role of ferulates in cell wall cross-linking and lignin formation in grasses. Just prior to lignification, cell elongation decelerates as ferulic and diferulic acids accumulate in cell walls. Growth rapidly slows and stops with the deposition of p-coumarate, which is primarily associated with cell wall lignification in grasses. Accretion of ferulate, diferulates and p-coumarate continues after growth ends, into the later stages of secondary wall formation. Although it comprises only 2% of the cell wall, over 50% of wall ferulates undergo dimerization, suggesting that xylan feruloylation is highly regulated during wall biosynthesis to permit extensive ferulate cross-linking at the onset of lignification. During lignification, ferulate and diferulates extensively copolymerize with lignin precursors, cross-linking xylans to lignin. Based on the kinetics of ferulate and diferulate incorporation into lignin and the predicted growth of lignin polymer, ferulates and diferulates appear to act as nucleation sites for lignin formation. Additional studies have also revealed that reductions in cell wall feruloylation impair the formation lignin in primary and secondary cell walls.