Study on lignin biosynthetic genes from tall fescue (Festuca arundinacea schreb.)

Lignin, an integral component of secondary cell wall is indispensable for normal growth of a plant. However, high lignin content in cell wall not only problematic in industrial processing of plants but it also decreases the digestibility of forages. Lignin biosynthesis involves many enzymatic reactions among which the reactions catalyzed by enzymes caffeic acid O-methyltransferase (EC. 2.1.1.68), cinnamoyl CoA reductase (EC. 1.2.1.44) and cinnamoyl alcohol dehydrogenase (EC.1.1.1.195) are important regulatory steps of the pathway. In the present study, gene fragments of COMT (caffeic acid O-methyl transferase), CCR (Cinnamoyl CoA reductase) and CAD (Cinnamoyl alcohol dehydrogenase) with 1058, 207 and 1166bp lengths, respectively were cloned and sequenced from tall fescue (Festuca arundinacea Schreb.) Phylogenetic analysis revealed that the COMT, CCR and CAD genes from tall fescue and other monocots separate in distinct groups. A close evolutionary relationship was observed between tall fescue with perennial ryegrass (Lolium perenne) as they shared same sub-branch of monocotyledons clade. The results from the study would be helpful in understanding intricacies of lignin biosynthesis and designing strategies for manipulating its content for improving digestibility of important forage species with high lignin content.