Distinct cinnamoyl CoA reductases involved in parallel routes to lignin in Medicago truncatula.

ABSTRACT: Cinnamoyl CoA reductases (CCR) convert hydroxycinnamoyl CoA esters to their corresponding cinnamyl aldehydes in monolignol biosynthesis. We identified two CCR genes in the model legume Medicago truncatula. CCR1 exhibits preference for feruloyl CoA, but CCR2 prefers caffeoyl and 4-coumaroyl CoAs, exhibits sigmoidal kinetics with these substrates, and is substrate-inhibited by feruloyl and sinapoyl CoAs. M. truncatula lines harboring transposon insertions in CCR1 exhibit drastically reduced growth and lignin content, whereas CCR2 knockouts grow normally with moderate reduction in lignin levels. CCR1 fully and CCR2 partially complement the irregular xylem gene 4 CCR mutation of Arabidopsis. The expression of caffeoyl CoA 3-O-methyltransferase (CCoAOMT) is up-regulated in CCR2 knockout lines;

SUBMITTER: Zhou R 

PROVIDER: S-EPMC2955080 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature