Genetic Diversity and Association Analysis for Carotenoid Content among Sprouts of Cowpea (Vigna unguiculata L. Walp)

Abstract

The development and promotion of biofortified foods plants are a sustainable strategy for supplying essential micronutrients for human health and nutrition. We set out to identify quantitative trait loci (QTL) associated with carotenoid content in cowpea sprouts. The contents of carotenoids, including lutein, zeaxanthin, and β-carotene in sprouts of 125 accessions were quantified via high-performance liquid chromatography. Significant variation existed in the profiles of the different carotenoids. Lutein was the most abundant (58 ± 12.8 mg/100 g), followed by zeaxanthin (14.7 ± 3.1 mg/100 g) and β-carotene (13.2 ± 2.9 mg/100 g). A strong positive correlation was observed among the carotenoid compounds (r ≥ 0.87), indicating they can be improved concurrently. The accessions were distributed into three groups, following their carotenoid profiles, with accession C044 having the highest sprout carotenoid content in a single cluster. A total of 3120 genome-wide SNPs were tested for association analysis, which revealed that carotenoid biosynthesis in cowpea sprouts is a polygenic trait controlled by genes with additive and dominance effects. Seven loci were significantly associated with the variation in carotenoid content. The evidence of variation in carotenoid content and genomic regions controlling the trait creates an avenue for breeding cowpea varieties with enhanced sprouts carotenoid content.

Genome-Wide Association Analysis Reveals Trait-Linked Markers for Grain Nutrient and Agronomic Traits in Diverse Set of Chickpea Germplasm

“…In comparison to cross-pollinated crops, LD decay was observed to be slower in self-pollinated crops [ 15 , 50 ]. The extent of LD decay in the association panel of chickpea was observed at 200–300 kb [ 51 ] and at 5 cM in chickpea reference set [ 20 ] and for cowpea at 1.4 Mb [ 52 ]. The extent of LD can vary due to the complexity and size of the genome and marker number [ 53 ].…”

An Integrated Approach for Biofortification of Carotenoids in Cowpea for Human Nutrition and Health

“…In contrast to TLC, liquid chromatography (LC) helps to achieve both the separation and quantification of specific carotenoids and their isomers. HPLC analyses using C18 and C30 columns as stationary phases have successfully been deployed for carotenoid analysis in cowpea [25,41,54,55]. Ultra-performance liquid chromatography (UPLC) and ultra-high-performance liquid chromatography (UHPLC) are modern LC techniques used for the separation of carotenoids in cowpea [40].…”

Crop Landraces and Indigenous Varieties: A Valuable Source of Genes for Plant Breeding

“…GWAS was performed to identify loci associated with crops’ nutrient status, enhancing biofortification efforts. In one of these studies, seven loci were identified through GWAS that were associated with the carotenoid content of sprouts of 125 cowpea accessions including landraces [ 92 ]. Moreover, a GWAS was undertaken recently on 161 accessions, including landrace material to identify markers related to cowpea seed protein content, in which three candidate genes were identified [ 93 ].…”