Genetic diversity associated with variation in silage corn digestibility for three O-methyltransferase genes involved in lignin biosynthesis

Abstract

Polymorphisms within three candidate genes for lignin biosynthesis were investigated to identify alleles useful for the improvement of maize digestibility. The allelic diversity of two caffeoyl-CoA 3-O-methyltransferase genes, CCoAOMT2 and CCoAOMT1, as well as that of the aldehyde O-methyltransferase gene, AldOMT, was evaluated for 34 maize lines chosen for their varying degrees of cell wall digestibility. Frequency of nucleotide changes averaged one SNP every 35 bp. Ninety-one indels were identified in non-coding regions and only four in coding regions. Numerous distinct and highly diverse haplotypes were identified at each locus. Numerous sites were in linkage disequilibrium that declined rapidly within a few hundred bases. For F4, an early flint French line with high cell wall digestibility, the CCoAOMT2 first exon presented many non-synonymous polymorphisms. Notably we found an 18-bp indel, which resembled a microsatellite and was associated with cell wall digestibility variation. Additionally, the CCoAOMT2 gene co-localized with a QTL for cell wall digestibility and lignin content. Together, these results suggest that genetic diversity investigated on a broader genetic basis could contribute to the identification of favourable alleles to be used in the molecular breeding of elite maize germplasm.

Structure and expression profile of the cinnamyl alcohol dehydrogenase gene and its association with lignification in the sorghum (Sorghum bicolor (L.) Moench) bmr-6 mutant

“…These findings suggest that the presence of multiple introns plays an important role in the acquisition of gene function, such as the incorporation of new functional domains; these introns are gradually lost during evolution. Studies of COMT genes in different species have indicated that the size and number of introns varies considerably among species (Besse et al 2009, Bout and Vermerris 2003, Guillet-Claude et al 2004. The CAD gene has lost introns during the evolutionary process, so we speculate that the presence of these introns in ancestral species was essential for the CAD gene to acquire new functional properties.…”

Cloning of a caffeoyl-coenzyme A O-methyltransferase from Camellia sinensis and analysis of its catalytic activity

“…1b and 1c), which was in concordance with the maize and Eragrostis curvula CCoAOMT1 gene intron-exon arrangement. In contrast, three introns were identified in rice CCoAOMT and maize CCoAOMT2 (Guillet-Claude et al, 2004).…”

Cell-Wall Composition and Accessibility to Hydrolytic Enzymes is Differentially Altered in Divergently Bred Switchgrass (Panicum virgatum L.) Genotypes

“…1, also see [29]) indicating that cell-wall composition and possibly architecture were altered due to selection. Cell-wall composition is a complex trait controlled through the actions of many genes [34][35][36][37], and it is likely that genotypes with altered lignin and DMD could arise from several different combinations of genes. Furthermore, lignin is a mixed polymer, composed of different aromatic compounds cross-linked to each other and to cell-wall carbohydrates [36][37][38][39].…”