Flavonoid Biosynthesis Genes in Triticum aestivum L.: Methylation Patterns in Cis-Regulatory Regions of the Duplicated CHI and F3H Genes

Abstract

Flavonoids are a diverse group of secondary plant metabolites that play an important role in the regulation of plant development and protection against stressors. The biosynthesis of flavonoids occurs through the activity of several enzymes, including chalcone isomerase (CHI) and flavanone 3-hydroxylase (F3H). A functional divergence between some copies of the structural TaCHI and TaF3H genes was previously shown in the allohexaploid bread wheat Triticum aestivum L. (BBAADD genome). We hypothesized that the specific nature of TaCHI and TaF3H expression may be induced by the methylation of the promoter. It was found that the predicted position of CpG islands in the promoter regions of the analyzed genes and the actual location of methylation sites did not match. We found for the first time that differences in the methylation status could affect the expression of TaCHI copies, but not the expression of TaF3Hs. At the same time, we revealed significant differences in the structure of the promoters of only the TaF3H genes, while the TaCHI promoters were highly homologous. We assume that the promoter structure in TaF3Hs primarily affects the change in the nature of gene expression. The data obtained are important for understanding the mechanisms that regulate the synthesis of flavonoids in allopolyploid wheat and show that differences in the structure of promoters have a key effect on gene expression.

Phylogenetic Analysis of R2R3-MYB Family Genes in Tetrastigma hemsleyanum Diels et Gilg and Roles of ThMYB4 and ThMYB7 in Flavonoid Biosynthesis

“…The flavonoid pathway is a branch pathway of phenylpropane metabolism, and the PAL , C4H , 4CL , CHS , CHI , F3H , and FLS genes play important roles in flavonoid biosynthesis [ 49 , 50 ]. When plants were subjected to abiotic stress, the expression levels of these key enzyme genes changed [ 51 , 52 ].…”

Molecular-Genetic Basis of Plant Breeding

“…This study was based on an enormous research effort that combined Bulked segregants analysis, RNA-seq, and metabolomics. The theoretical background was thoroughly studied in the model Arabidopsis species, where BIG3 and BIG5 genes redundantly mediated vesicle trafficking transport of various substances within cells [ 10 ] while cis -regulatory regions of some duplicated genes resulted in very important methylation patterns of flavonoid biosynthesis genes in bread wheat [ 11 ]. Therefore, this Special Issue represents the excellent achievements of molecular genetic analyses in plants which can and certainly will be used in practical plant breeding.…”