Variability of carotenoid synthesis and degradation genes in Russian durum wheat cultivars.

Abstract

Yellow index is an important quality parameter of durum wheat cultivars, associated with carotenoid pigment content in grain and the level of carotenoid degradation during processing, and determining the yellow color of products made from durum wheat. Molecular markers of genes that influence carotenoid content can be used for fast identification of valuable genotypes and development of new high-quality durum wheat cultivars. The aim of the study was to investigate the domestic durum wheat gene pool using molecular markers of the yellow pigment synthesis (Psy-A1) and degradation (Lpx-B1) genes. Using two markers of the phytoene synthase Psy- A1 gene (PSY1-A1_STS and YP7A-2) and three markers of the lipoxygenase Lpx-B1 locus (Lpx-B1.1a/1b, Lpx- B1.1c and Lpx- B1.2/1.3), 54 durum wheat cultivars were studied for the first time. For 38 cultivars, yellow pigment content in grain was also assessed. The detected allelic variation of the phytoene synthase Psy-A1 and lipoxygenase Lpx-B1 genes was rather low. The most common Psy-A1 alleles among the studied cultivars were Psy-A1l for the PSY1- A1_STS marker and Psy-A1d for the YP7A-2 marker, identified in 51 cultivars and associated with high carotenoid content. According to the markers of the Lpx-B1 locus, haplotype II, associated with medium lipoxygenase activity, identified in 43 cultivars, was predominant. Haplotype III, associated with low enzyme activity, was identified in only three winter durum wheat cultivars (Donchanka, Gelios and Leucurum 21). Despite the predominance of allelic variants associated with increased carotenoid content and moderate lipoxygenase activity, the studied cultivars had different levels of yellow pigment content in grain, from low to high.