Key Targets from a Complex Family of Lignin Biosynthesis Genes Identified in Switchgrass
Although lignin content and composition have been manipulated in several plant species by targeting the monolignol biosynthesis pathway, little is known about the genes and enzymes associated with this pathway in switchgrass. Cinnamoyl CoA reductase (CCR) catalyzes the first step in this pathway dedicated to monolignol synthesis. However, switchgrass contains numerous copies of CCR-like genes,
complicating the selection of the best gene targets for altering lignin to reduce cell-wall recalcitrance. By analyzing the RNA of expressed CCR genes, BESC researchers show that one of the expressed genes (PvCCR1) encodes an enzyme actively involved in lignification and thus is a prime target for down-regulation to improve the degradability and sugar yield from switchgrass. Ongoing research is investigating how reducing the expression of the PvCCR1 gene impacts lignin composition and plant structure.
This research was reported in Escamilla-Treviño, L. L., et al. 2009. “Switchgrass (Panicum
virgatum) Possesses a Divergent Family of Cinnamoyl CoA Reductases with Distinct Biochemical Properties,” New Phytologist 185, 143–55.