Expression patterns of genes involved in starch biosynthesis during seed development in bread wheat (Triticum aestivum)

In agricultural crops, seed growth is important for high grain yield. Starch contributes about 50–80 % of the dry weight of seed, and its quality affects both processing and nutrition quality. Despite the wider importance of starch metabolism, the genes involved have not been given much attention or exploited for their use in molecular breeding. Therefore, it is of great interest to analyze the expression of genes involved in starch metabolism for improvement of starch-related traits through molecular breeding. In this study, a quantitative gene expression analysis of 25 starch metabolism genes was conducted in three bread wheat (Triticum aestivum) genotypes differing in yield- and starch-related traits at five seed developmental stages, i.e., 7, 14, 21, 28, and 35 days after anthesis. Their sequences were physically mapped to chromosomes using the wheat genome sequence data through in silico analysis. Their expression data showed dynamic variation during seed development in wheat genotypes. The 25 genes were divided into four groups depending on their expression patterns during seed development. For example, one group was characterized by a high level of expression at early and middle stages as exhibited by different isoforms of starch synthases, starch-branching enzymes, isoamylase, and transcription factors (TaRSR1 and SPA). The enzymes of these genes are key factors in starch biosynthesis. The starch metabolism genes with high expression levels will be sequenced in a wheat germplasm set to develop single nucleotide polymorphism markers for improvement of yield- and starch-related traits through molecular breeding approaches.