Harnessing Traits Across The Legumes to Develop Climate Resilient Crops

Of the approximately 20,000 species in the legume family, many grow in harsh and extreme environments. Learning about the molecular, anatomical, and physiological basis for these adaptations may enable modification of crop legumes to make them more tolerant of more climatic conditions -- both under new climatic regimes, and outside of traditional ranges for these crop plants. Some legume adaptations include: flooding tolerance (e.g. Apios, Sesbania); aquatic adaptation (e.g. Neptunia); saline tolerance (e.g. Lotus, Prosopis); heat and drought tolerance (e.g. Astragalus, Lupinus, Bituminaria, Acacia); cold tolerance (e.g. Lupinus, Trifolium). A number of minor crops, as well as secondary and tertiary germplasm for major crops, already have remarkable adaptations, and may be suitable either for domestication, introgression, or gene transfer to established crops. Some noteworthy "extremophile minor crops" are Cordeauxia edulis (Yeheb nut, a Sub-Saharan African shrub); Tylosema esculentum (Marama bean, a tuberous vine from the African Kalahari); and Prosopis glandulosa (honey locust, a shrub from the American South-West); and Apios americana (potato bean, a drought-tolerant, tuber-producing bean from the Eastern United States). Among the "secondary and tertiary germplasm" of major crops are several Australian relatives of soybean: Glycine canescens and Glycine tomentella, from Australia, with drought and heat tolerance; numerous Vigna species and accessions, with heat and drought tolerance; and Phaseolus acutifolius (tepary bean, native to Mexico and the South Western United States). Comparative genomic methods are beginning to identify loci responsible for useful traits, as well as the corresponding regions in some crops.