Abiotic Stress Tolerance Including Salt, Drought and Metal(loid)s in Legumes

Abstract

The Leguminosae family constitutes the second most important family of crop plants worldwide. Nowadays, legumes provide one-third of the entire amount of protein for human consumption, animal food and edible and industrial oils. Plants are prone to suffer stress episodes such as salinity, drought or the presence of metal(loid)s. On initial exposure to an abiotic stress, plants show alterations in metabolism, ionic balance, osmolarity and membrane stability, among others. An oxidative burst with consequent biomolecules damage aggravates the stress condition. Along the evolution, plants acquired stress-specific cellular sensing mechanisms that help in signal transduction, yielding the activation of transcription factors and genes to counteract the deleterious effects triggered by the stressful condition. Among the contributors to help the plant in re-establishing cellular homeostasis are ion balancing, compatible solutes accumulation, antioxidant defense, hormonal regulation. However, depending on the severity of the stress, plants can retard or cease growth and finally die. Thus, this can conduct to yield loss having a huge impact in agroeconomy.Therefore, the present chapter focuses on the tolerance mechanisms to salinity, drought stress and metal(loid)s and summarizes the human efforts that upraised in an exhaustive tentative for improve stress tolerance in legume crops. This chapter intends to increase the understanding of the tolerance mechanisms evoked by legumes exposed to abiotic stresses, hence avoiding yield loss. The biochemical, molecular and physiological responses triggered by plants to cope with abiotic stresses are presented. Besides, we discuss the last advances in legume improvement through transgenic, breeding or agronomic approaches.