Khan Dawood, Cai Nan, Zhu Weilin, Li Leilin, Guan Miao, Pu Xiaojun, Chen Qi
Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China.
Front Plant Sci. 2023 Mar 10;14:1142753. doi: 10.3389/fpls.2023.1142753. eCollection 2023.
Phytomelatonin is a pleiotropic signaling molecule that regulates plant growth, development, and stress response. In plant cells, phytomelatonin is synthesized from tryptophan several consecutive steps that are catalyzed by tryptophan decarboxylase (TDC), tryptamine 5-hydroxylase (T5H), serotonin -acyltransferase (SNAT), and -acetylserotonin methyltransferase (ASMT) and/or caffeic acid-3--methyltransferase (COMT). Recently, the identification of the phytomelatonin receptor PMTR1 in has been considered a turning point in plant research, with the function and signal of phytomelatonin emerging as a receptor-based regulatory strategy. In addition, PMTR1 homologs have been identified in several plant species and have been found to regulate seed germination and seedling growth, stomatal closure, leaf senescence, and several stress responses. In this article, we review the recent evidence in our understanding of the PMTR1-mediated regulatory pathways in phytomelatonin signaling under environmental stimuli. Based on structural comparison of the melatonin receptor 1 (MT1) in human and PMTR1 homologs, we propose that the similarity in the three-dimensional structure of the melatonin receptors probably represents a convergent evolution of melatonin recognition in different species.
植物褪黑素是一种多效性信号分子，可调节植物的生长、发育和应激反应。在植物细胞中，植物褪黑素由色氨酸经过几个连续步骤合成，这些步骤由色氨酸脱羧酶（TDC）、色胺5-羟化酶（T5H）、血清素-N-乙酰基转移酶（SNAT）和N-乙酰血清素甲基转移酶（ASMT）和/或咖啡酸-3-O-甲基转移酶（COMT）催化。最近，在[具体物种]中植物褪黑素受体PMTR1的鉴定被认为是植物研究中的一个转折点，植物褪黑素的功能和信号作为一种基于受体的调控策略逐渐显现。此外，在几种植物物种中已鉴定出PMTR1同源物，并发现它们可调节种子萌发和幼苗生长、气孔关闭、叶片衰老以及多种应激反应。在本文中，我们综述了近期关于在环境刺激下植物褪黑素信号中PMTR1介导的调控途径的理解证据。基于人类褪黑素受体1（MT1）和PMTR1同源物的结构比较，我们提出褪黑素受体三维结构的相似性可能代表了不同物种中褪黑素识别的趋同进化。
