On the diversity of roles of organic acids

Organic acids play an integral role in plant primary metabolism, where they are involved in fundamental pathways such as, the tricarboxylic acid cycle, C3-, C4- and CAM-photosynthesis and the glyoxylate cycle. They also arise as products of the degradation of more reduced compounds and are interconverted in many plant tissues. Organic acids, such as malate, fumarate, lactate, and citrate, have essential functions in many cellular processes such as stomatal function, phosphorous acquisition, aluminium tolerance, communication with microorganisms, CO2 concentrating metabolism, temporary carbon storage, interchange of reductive power among subcellular compartments, and pH regulation. They also play a critical role in the regulation of plant development and growth, as well as in regulation of both primary and specialized metabolic pathways, some of which are involved in the response to both abiotic and biotic stress. Moreover, they play roles as signalling molecules, not only as allosteric regulators of many key enzymes, but also as modulators of gene expression.
Therefore, it is valuable to overview recent progress and concepts on the diverse role of organic acids in plants, even more considering the unexpected physiological roles that have been revealed in the last years for these `old known´ metabolites. This research topic collects contributions from different facets of plant biology to bring together, and integrate in a comprehensive view the latest advances in our understanding of the multiple functions of plant organic acids, as well as of the diverse metabolic pathways involved in the metabolism of these compounds. We welcome all types of articles related to the role and involvement of organic acids in plant cellular functions, including original research papers, reviews, mini reviews, methods, commentaries, and opinions.