Natural variation of folate content in cowpea (Vigna unguiculata) germplasm and its correlation with the expression of the GTP cyclohydrolase I coding gene

Cowpea (Vigna unguiculata) is one of the most important sources of vitamins, protein, and minerals for Africa, Latin America and Asia. In addition, grains are a rich source of folates. Folates are cofactors for the one-carbon transfer reactions needed for many biochemical processes. Their deficiency is associated with several diseases. In this study, we investigated variation in total folate levels in cowpea genotypes from Northern Brazil, Western Africa and Southwestern Asia and the correlation with VugchI gene expression. Results revealed that VugchI transcripts were observed in all studied developmental stages [10-, 15-, 20- and 25-days post anthesis (dpa)], reaching a maximum at 20 dpa. Folate content ranged from 780.7-177.2 mu g/100 g of dried seeds, and the highest amounts were observed in traditional varieties cultivated in Nigeria and Northern Brazil. A statistically significant correlation was observed between the amounts of total folate and the expression of the VugchI gene at 20 dpa. Data showed a large variation in the total folate content that could be exploited by breeding programs to generate higher-folate varieties. It would be important to combine both high folate content and agriculturally relevant traits, which would lead farmers to adopt modern varieties enriched with folates.

Automated summary

This study investigated the variations in total folate levels in different genotypes of cowpea and their correlation with the expression of a specific gene. The results showed a large variation in folate content among cowpea genotypes, with the highest levels observed at 20 days after anthesis. Additionally, there was a significant correlation between the folate content and the expression of the specific gene. These findings have important implications for breeding programs and the development of cowpea varieties with high folate content.