Roles of malic enzymes in plant development and stress responses.

Malic enzyme (ME) comprises a family of proteins with multiple isoforms located in different compartments of eukaryotic cells. It is a key enzyme regulating malic acid metabolism and can catalyze the reversible reaction of oxidative decarboxylation of malic acid. And it is also one of the important enzymes in plant metabolism and is involved in multiple metabolic processes. ME is widely present in plants and mainly discovered in cytoplasmic stroma, mitochondria, chloroplasts. It is involved in plant growth, development, and stress response. Plants are stressed by various environmental factors such as drought, high salt, and high temperature during plant growth, and the mechanisms of plant response to various environmental stresses are synergistic. Numerous studies have shown that ME participates in the process of coping with the above environmental factors by increasing water use efficiency, improving photosynthesis of plants, providing reducing power, and so on. In this review, we discuss the important role of ME in plant development and plant stress response, and prospects for its application. It provides a theoretical basis for the future use of ME gene for molecular resistance breeding.