Jalili Shabnam, Ehsanpour Ali Akbar, Javadirad Seyed Morteza
Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran.
Department of Cell and Molecular Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran.
Bot Stud. 2022 Jun 11;63(1):19. doi: 10.1186/s40529-022-00348-7.
Alfalfa (Medicago sativa L.) is the most cultivated forage plant as a model in legumes. Salinity stress due to Na toxicity causes severe, oxidative stress as a main reason for program cell death (PCD) in plants. Melatonin application can increase plant productivity in response to diverse stressors via modulating plant antioxidant mechanisms and PCD inhibition in plants.
Alfalfa roots were subjected to different concentrations of in vitro salinity supplemented with melatonin (0.1, 10 and 15 µM) for ten days. Application of melatonin under salinity stress reduced ROS, HO and [Formula: see text] content and showed a dramatic impact on TTC reduction and augmented cell viability. Interestingly, melatonin inhibited caspase 3-like protease activity and could decrease DNA fragmentation induced by salinity while increased expression of anti-apoptotic genes BI-1, UCP1-UCP2 involved in PCD pathway. In contrast, in 300 mM salinity, γVPE gene as a proapoptotic of PCD down-regulated significantly.
For the first time, present data showed that, melatonin plays a major function in preventing PCD in alfalfa root meristem cells. We attempted to offer a mechanism for the function of melatonin as an anti-apoptotic agent by demonstrating significant actions of melatonin on mitochondria proteins, such as UCPs, in a manner similar to animal cells.
紫花苜蓿（Medicago sativa L.）是豆科中种植最为广泛的饲用植物模型。由于钠毒性导致的盐胁迫会引发严重的氧化应激，这是植物程序性细胞死亡（PCD）的主要原因。褪黑素的施用可通过调节植物抗氧化机制和抑制植物中的PCD来提高植物对多种胁迫的耐受性。
将苜蓿根置于添加了褪黑素（0.1、10和15 μM）的不同浓度的体外盐胁迫环境中处理十天。在盐胁迫下施用褪黑素可降低活性氧（ROS）、羟基自由基（HO）和[公式：见原文]的含量，并对氯化三苯基四氮唑（TTC）还原产生显著影响，增强细胞活力。有趣的是，褪黑素抑制了类半胱天冬酶3蛋白酶的活性，可减少盐胁迫诱导的DNA片段化，同时增加了PCD途径中抗凋亡基因BI-1、UCP1-UCP2的表达。相反，在300 mM盐浓度下，作为PCD促凋亡因子的γVPE基因显著下调。
目前的数据首次表明，褪黑素在防止苜蓿根分生组织细胞发生PCD中发挥主要作用。我们试图通过证明褪黑素对线粒体蛋白（如解偶联蛋白）具有与动物细胞类似的显著作用，来为褪黑素作为抗凋亡剂的功能提供一种机制。
