Abiotic Stress Responses in Legumes: Strategies Used toCope with Environmental Challenges

Legumes are well recognized for their nutritional and health benefits as well as for their impact in the sustainability of agricultural systems. The threatening scenario imposed by climate change highlights the need for concerted research approaches in order to develop crops that are able to cope with environmental stresses, while increasing yield and quality. During the last decade, some physiological components and molecular players underlying abiotic stress responses of a broad range of legume species have been elucidated. Plant physiology approaches provided general outlines of plant responses, identifying stress tolerance-related traits or elite cultivars. A thorough identification of candidate genes and quantitative trait loci (QTLs) associated with these traits followed. Model legumes like Medicago truncatula, Lotus japonicus, and more recently, Glycine max provided valuable translational approaches for dissecting legume responses to abiotic stresses. The challenge now focuses on the translation of the information gained in model systems in controlled environments to crops grown under field conditions. In this review, we provide a general overview of the recent achievements on the study of abiotic stress responses in a broad range of model, grain and forage legumes species, highlighting the different approaches used. Major accomplishments, as well as limitations or drawbacks are discussed across the different sections. Some perspectives regarding new approaches for screening, breeding or engineering legumes with desirable abiotic stress resistance traits are anticipated. These advances will support the development of legumes better adapted to environmental constraints, tackling current demands on modern agriculture and food production presently exacerbated by global climate changes.