Identification and epistasis analysis of quantitative trait loci for zeaxanthin concentration in maize kernel across different generations and environments

Abstract

Zeaxanthin, a natural fat-soluble pigment, not only increases plant resistance, but also has vital significance for human health. However, quantitative trait loci (QTL) and the epistatic effects of zeaxanthin concentration in maize kernel have not been well studied. To identify QTLs and analyse the epistatic effects of zeaxanthin concentration in maize kernel, two sets of segregating generations derived from the cross between HuangC (a high zeaxanthin concentration inbred line) and Rezi1 (a low zeaxanthin concentration inbred line) were evaluated in three different environments. One major-effect QTL, qZea6a, explains 41.4-71.4% of the phenotypic variation and two QTLs, qZea4a and qZea3a, show LOD > 3 for zeaxanthin concentration detected over two generations and three different environments. Four of the ten QTL pairs show epistatic effects, explaining 7.34-14.3% of the phenotypic variance. Furthermore, additivity was the major allelic action at zeaxanthin concentration QTLs located in F 2 and F 2:3 populations and plants with homozygous HuangC alleles have a strong genetic ability in enhancing zeaxanthin concentration in maize kernel. These results will contribute to understanding these complex loci better and provide awareness about zeaxanthin concentration to maize breeders and scientists involved in maize research.

Regulation of Plant Vitamin Metabolism: Backbone of Biofortification for the Alleviation of Hidden Hunger

“…ZmcrtRB3, a carotenoid hydroxylase gene in maize, was mapped to a QTL with polymorphisms that contributed more to a-carotene than to b-carotene (Zhou et al, 2012). Moreover, some studies have also identified QTLs responsible for ε-carotenoid accumulation in chickpea and maize (Abbo et al, 2005;Chander et al, 2008), b-cryptoxanthin in citrus (Sugiyama et al, 2011), and zeaxanthin in potato (Wolters et al, 2010) and maize (Wong et al, 2004;Chander et al, 2008;Dong et al, 2020a).…”

QTL Mapping of Zeaxanthin Content in Sweet Corn Using Recombinant Inbred Line Population across Different Environments

“…It was reported that the quantitative trait loci (QTL) for zeaxanthin on chromosome 6 account for 13.9-16.3% of the phenotypic variation [34,35]. Dong et al found that the QTL qZea6a on chromosome 6 accounts for 41.4-71.4% of the phenotypic variation [36]. This might be due to the large genetic differences in zeaxanthin genes between the two parents.…”

“…Similarly, to identify major loci controlling carotenoid content in maize grains, a genetic linkage map was constructed from 233 recombinant inbred lines by crossing maize inbred lines By804 and B73, and a total of 31 putative QTLs, including 23 for individual and 8 for total carotenoids, were detected; furthermore, five QTLs associated with zeaxanthin were located on chromosomes 1, 6, 8, and 10, which accounted for 3.8-16.6% of the phenotypic variation [35]. Subsequently, the major-effect QTL qZea6a explained 41.4-71.4% of the phenotypic variation, and two more QTLs, qZea4a and qZea3a showed LOD > 3 for zeaxanthin concentration in two generations and three different environments [36]. In short, few studies have detected zeaxanthin-related QTLs in maize and, although it is a particularly good source of zeaxanthin, knowledge of zeaxanthin regulation in sweet corn remains limited.…”