Sugarcane expressed sequences tags (ESTs) encoding enzymes involved in lignin biosynthesis pathways

Abstract

Lignins are phenolic polymers found in the secondary wall of plant conductive systems where they play an important role by reducing the permeability of the cell wall to water. Lignins are also responsible for the rigidity of the cell wall and are involved in mechanisms of resistance to pathogens. The metabolic routes and enzymes involved in synthesis of lignins have been largely characterized and representative genes that encode enzymes involved in these processes have been cloned from several plant species. The synthesis of lignins is liked to the general metabolism of the phenylpropanoids in plants, having enzymes (e.g. phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H) and caffeic acid O-methyltransferase (COMT)) common to other processes as well as specific enzymes such as cinnamoyl-CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD). Some maize and sorghum mutants, shown to have defective in CAD and/or COMT activity, are easier to digest because they have a reduced lignin content, something which has motivated different research groups to alter the lignin content and composition of model plants by genetic engineering try to improve, for example, the efficiency of paper pulping and digestibility. In the work reported in this paper, we have made an inventory of the sugarcane expressed sequence tag (EST) coding for enzymes involved in lignin metabolism which are present in the sugarcane EST genome project (SUCEST) database. Our analysis focused on the key enzymes ferulate-5-hydroxylase (F5H), caffeic acid O-methyltransferase (COMT), caffeoyl CoA O-methyltransferase (CCoAOMT), hydroxycinnamate CoA ligase (4CL), cinnamoyl-CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD). The comparative analysis of these genes with those described in other species could be used as molecular markers for breeding as well as for the manipulation of lignin metabolism in sugarcane.

RNAi suppression of lignin biosynthesis in sugarcane reduces recalcitrance for biofuel production from lignocellulosic biomass

“…, 1999). In sugarcane, ∼31 different consensus EST sequences are clustered to COMT , which could be potential allelic variants or homo(eo)logous genes (Ramos et al. , 2001).…”

Lignification in Sugarcane: Biochemical Characterization, Gene Discovery, and Expression Analysis in Two Genotypes Contrasting for Lignin Content

“…Despite the recent advances achieved with model plants such as Arabidopsis (Arabidopsis thaliana), poplar (Populus spp. ), and maize (Zea mays), information on lignin metabolism in sugarcane is scarce, and only a few genes have been identified from large-scale transcript profiling studies (Ramos et al, 2001;Papini-Terzi et al, 2005). In this regard, a combination of coexpression analysis, tissue/ cell type-specific expression analysis, and genetic complementation was recently used to correlate a laccase gene to the lignification process in sugarcane .…”

Identification of simple sequence repeat markers for sweetpotato weevil resistance

“…Hydroxycinnamic acid esters have been shown to play key roles in the biosynthesis pathway of lignin, a key mode of plant defense against pathogenic attack and herbivory (Boerjan et al 2003). Single genes were isolated and shown to encode the enzymes for lignin biosynthesis including hydroxycinnamate CoA ligase (4CL) in sugarcane (Ramos et al 2001). The mode of inheritance of HCA esters in sweetpotato needs to be understood for enhancing their application in improving SPW resistance.…”