The mechanism of alfalfa (Medicago sativa L.) response to abiotic stress

As plants are sessile, they cannot escape exposure to multiple environmental stresses. Over the course of evolution, a range of morphological and physiological adaptations has been developed in order to maximize their chances of survival. Alfalfa (Medicago sativa L.) is the most extensively cultivated forage legume in the world, while its yield and growing range are limited by abiotic stress. Physiology, genetic and molecular level studies have revealed complex regulatory processes that coordinate stress adaptation and tolerance, which are integrated at various levels. This review summarizes the current body of knowledge regarding the physiological, transcriptional, metabolic and genetic/epigenetic basis of the alfalfa stress response, along with the key signal transduction processes involved. Gathering the knowledge together will contribute to a more systematic understanding of the adaption to stress response in alfalfa, as well as provide guidance towards improving the crop through breeding.