Under-Exploited Wild Vigna Species Genetic Resources: An Insight from the Lipid and Mineral Profile Towards Improvement or Neo-Domestication

Abstract

Global efforts to end hunger are about more than producing enough food; they are also about producing food that is nutritious enough. Micronutrient deficiencies—the “hidden hunger” affecting billions—persist in part because the domestication bottleneck quietly eroded mineral and lipid diversity from the very crops the world relies on most. Wild relatives of domesticated legumes still carry much of that diversity, and genetic biofortification offers a sustainable route to put it back to work. Wild Vigna germplasm remains poorly characterized for traits that could support nutritional biofortification and neo-domestication. With that in mind, we characterized the seed mineral and fatty acid composition of 86 accessions from four wild Vigna species (V. vexillata, V. ambacensis, V. reticulata and V. racemosa), benchmarked against three domesticated (cultivars) and semi-domesticated checks (V. unguiculata, V. umbellata and V. vexillata landrace). Copper, manganese, zinc and iron were quantified by flame atomic absorption spectrophotometry after dry-ash digestion, and fatty acids were profiled as methyl esters by GC-MS. The species differed systematically in their mineral profiles. V. reticulata stood out as the most promising donor for copper-focused breeding, V. vexillata carried the highest median Zn, Mn and Fe values and is attractive for multi-micronutrient improvement, V. ambacensis showed a more stable but less extreme profile, and V. racemosa combined a relatively high Fe concentration with the most nutritionally favorable lipid profile of all—dominated by the essential polyunsaturated linoleic (C18:2n 6) and α-linolenic (C18:3n 3) acids. The other three wild species, by contrast, were dominated by saturated palmitic (C16:0) and stearic (C18:0) acids, which gives their oils greater oxidative stability and different food-industry applications. Principal component analysis supported these patterns for both datasets—minerals (PC1 = 60.39%, PC2 = 20.21%; cumulative 80.61%) and fatty acids (PC1 = 81.6%, PC2 = 14.0%; cumulative 95.6%)—and cleanly separated V. racemosa and the checks from the remaining wild species on lipid composition. Together, these results identify concrete targets for marker-assisted biofortification and de novo domestication of four African Vigna taxa.