National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India.
Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
J Exp Bot. 2021 May 18;72(11):4038-4052. doi: 10.1093/jxb/erab019.
Organic acids (OAs) are central to cellular metabolism. Many plant stress responses involve the exudation of OAs at the root-soil interface, which can improve soil mineral acquisition and toxic metal tolerance. Because of their simple structure, the low-molecular-weight OAs are widely studied. We discuss the conventional roles of OAs, and some newly emerging roles in plant stress tolerance. OAs are more versatile in their role in plant stress tolerance and are more efficient chelating agents than other acids, such as amino acids. Root OA exudation is important in soil carbon sequestration. These functions are key processes in combating climate change and helping with more sustainable food production. We briefly review the mechanisms behind enhanced biosynthesis, secretion, and regulation of these activities under different stresses, and provide an outline of the transgenic approaches targeted towards the enhanced production and secretion of OAs. A recurring theme of OAs in plant biology is their role as 'acids' modifying pH, as 'chelators' binding metals, or as 'carbon sources' for microbes. We argue that these multiple functions are key factors for understanding these molecules' important roles in plant stress biology. Finally, we discuss how the functions of OAs in plant stress responses could be used, and identify the important unanswered questions.
有机酸（OAs）是细胞代谢的核心。许多植物的应激反应都涉及到在根-土界面分泌 OAs，这可以提高土壤矿物的获取和有毒金属的耐受性。由于其结构简单，低分子量的 OAs 被广泛研究。我们讨论了 OAs 在植物应激耐受中的传统作用，以及一些新出现的作用。OAs 在植物应激耐受中的作用更加多样化，并且比其他酸（如氨基酸）更有效地螯合金属。根 OAs 的分泌对于土壤碳封存很重要。这些功能是应对气候变化和帮助实现更可持续粮食生产的关键过程。我们简要回顾了在不同胁迫下增强这些活性的生物合成、分泌和调控的机制，并提供了针对 OAs 增强生产和分泌的转基因方法概述。OAs 在植物生物学中的一个反复出现的主题是它们作为“酸”调节 pH 值、作为“螯合剂”结合金属，或作为微生物的“碳源”的作用。我们认为，这些多种功能是理解这些分子在植物应激生物学中重要作用的关键因素。最后，我们讨论了如何利用 OAs 在植物应激反应中的功能，并确定了重要的未解决问题。
