Yang Jianchang, Zhou Yujiao, Jiang Yi
Jiangsu Key Laboratory of Crop Genetics and Physiology, Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
Plants (Basel). 2022 Jun 15;11(12):1581. doi: 10.3390/plants11121581.
Rice is one of the most important food crops in the world, and amino acids in rice grains are major nutrition sources for the people in countries where rice is the staple food. Phytohormones and plant growth regulators play vital roles in regulating the biosynthesis of amino acids in plants. This paper reviewed the content and compositions of amino acids and their distribution in different parts of ripe rice grains, and the biosynthesis and metabolism of amino acids and their regulation by polyamines (PAs) and phytohormones in filling grains, with a focus on the roles of higher PAs (spermidine and spermine), ethylene, and brassinosteroids (BRs) in this regulation. Recent studies have shown that higher PAs and BRs (24-epibrassinolide and 28-homobrassinolide) play positive roles in mediating the biosynthesis of amino acids in rice grains, mainly by enhancing the activities of the enzymes involved in amino acid biosynthesis and sucrose-to-starch conversion and maintaining redox homeostasis. In contrast, ethylene may impede amino acid biosynthesis by inhibiting the activities of the enzymes involved in amino acid biosynthesis and elevating reactive oxygen species. Further research is needed to unravel the temporal and spatial distribution characteristics of the content and compositions of amino acids in the filling grain and their relationship with the content and compositions of amino acids in different parts of a ripe grain, to elucidate the cross-talk between or among phytohormones in mediating the anabolism of amino acids, and to establish the regulation techniques for promoting the biosynthesis of amino acids in rice grains.
水稻是世界上最重要的粮食作物之一，稻米中的氨基酸是水稻为主食的国家人们的主要营养来源。植物激素和植物生长调节剂在调节植物氨基酸生物合成中起着至关重要的作用。本文综述了成熟稻米籽粒中氨基酸的含量、组成及其在不同部位的分布，以及灌浆籽粒中氨基酸的生物合成与代谢及其受多胺（PAs）和植物激素的调控，重点关注高级PAs（亚精胺和精胺）、乙烯和油菜素内酯（BRs）在该调控中的作用。最近的研究表明，高级PAs和BRs（24-表油菜素内酯和28-高油菜素内酯）在介导稻米籽粒氨基酸生物合成中发挥积极作用，主要是通过增强参与氨基酸生物合成和蔗糖-淀粉转化的酶的活性以及维持氧化还原稳态。相反，乙烯可能通过抑制参与氨基酸生物合成的酶的活性和提高活性氧水平来阻碍氨基酸生物合成。需要进一步研究以阐明灌浆籽粒中氨基酸含量和组成的时空分布特征及其与成熟籽粒不同部位氨基酸含量和组成的关系，阐明植物激素之间在介导氨基酸合成代谢中的相互作用，并建立促进稻米籽粒氨基酸生物合成的调控技术。
