Sun Shoujiang, Ma Wen, Jia Zhicheng, Ou Chengming, Li Manli, Mao Peisheng
Forage Seed Laboratory, College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.
Antioxidants (Basel). 2023 Sep 15;12(9):1768. doi: 10.3390/antiox12091768.
Seed aging, a common physiological phenomenon during forage seed storage, is a crucial factor contributing to a loss of vigor, resulting in delayed seed germination and seedling growth, as well as limiting the production of hay. Extensive bodies of research are dedicated to the study of seed aging, with a particular focus on the role of the production and accumulation of reactive oxygen species (ROS) and the ensuing oxidative damage during storage as a primary cause of decreases in seed vigor. To preserve optimal seed vigor, ROS levels must be regulated. The excessive accumulation of ROS can trigger programmed cell death (PCD), which causes the seed to lose vigor permanently. LESION SIMULATING DISEASE (LSD) is one of the proteins that regulate PCD, encodes a small C2C2 zinc finger protein, and plays a molecular function as a transcriptional regulator and scaffold protein. However, genome-wide analysis of genes has not been performed for alfalfa (), as one of the most important crop species, and, presently, the molecular regulation mechanism of seed aging is not clear enough. Numerous studies have also been unable to explain the essence of seed aging for gene regulating PCD and affecting seed vigor. In this study, we obtained six genes in total from the alfalfa (cultivar Zhongmu No. 1) genome. Phylogenetic analysis demonstrated that the genes could be classified into three subgroups. In addition, six genes were unevenly mapped on three chromosomes in alfalfa. Gene duplication analysis demonstrated that segmental duplication was the key driving force for the expansion of this gene family during evolution. Expression analysis of six genes in various tissues and germinating seeds presented their different expressions. RT-qPCR analysis revealed that the expression of three genes, including , , and , was significantly induced by seed aging treatment, suggesting that they might play an important role in maintaining seed vigor. Although this finding will provide valuable insights into unveiling the molecular mechanism involved in losing vigor and new strategies to improve alfalfa seed germinability, additional research must comprehensively elucidate the precise pathways through which the genes regulate seed vigor.
种子老化是牧草种子储存过程中常见的生理现象，是导致种子活力丧失的关键因素，会致使种子萌发和幼苗生长延迟，还会限制干草产量。大量研究致力于种子老化的研究，尤其关注活性氧（ROS）的产生和积累以及储存期间随之而来的氧化损伤作为种子活力下降的主要原因所起的作用。为了保持最佳种子活力，必须调节ROS水平。ROS的过度积累会触发程序性细胞死亡（PCD），从而导致种子永久丧失活力。损伤模拟病（LSD）是调节PCD的蛋白质之一，编码一种小的C2C2锌指蛋白，并作为转录调节因子和支架蛋白发挥分子功能。然而，尚未对紫花苜蓿（作为最重要的作物品种之一）进行全基因组基因分析，目前种子老化的分子调控机制尚不清楚。许多研究也无法解释调控PCD并影响种子活力的基因导致种子老化的本质。在本研究中，我们总共从紫花苜蓿（品种中苜1号）基因组中获得了6个LSD基因。系统发育分析表明，LSD基因可分为三个亚组。此外，6个LSD基因在紫花苜蓿的三条染色体上分布不均。基因复制分析表明，片段重复是该基因家族在进化过程中扩张的关键驱动力。对6个LSD基因在不同组织和萌发种子中的表达分析呈现出它们的不同表达情况。RT-qPCR分析表明，包括MsLSD1、MsLSD2和MsLSD3在内的3个LSD基因的表达受到种子老化处理的显著诱导，表明它们可能在维持种子活力方面发挥重要作用。尽管这一发现将为揭示活力丧失所涉及的分子机制以及提高苜蓿种子发芽率的新策略提供有价值的见解，但还需要进一步研究全面阐明LSD基因调控种子活力的确切途径。
