Sun Shoujiang, Ma Wen, Mao Peisheng
Forage Seed Laboratory, College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.
Plants (Basel). 2023 May 19;12(10):2036. doi: 10.3390/plants12102036.
Seed aging is always taken as a crucial factor for vigor loss due to delayed seed germination and seedling growth, which limits hay production. Many studies have found that telomeres are closely related to abiotic stress and seed vigor. However, the molecular mechanism of telomeres' response to abiotic stress, seed vigor, and the maintenance mechanism of plant telomere homeostasis still remain unclear. Alfalfa () enjoys the title of "King of Forage", and is an important protein forage for the dairy industry as planted in the world. This comprehensive investigation was performed to explore the molecular characterization, phylogenetic relationship, and gene expression analysis of under abiotic stress and during seed aging in alfalfa. In this study, was identified from the 'Zhongmu 1' alfalfa genome and encoded a coding sequence (CDS) of 3615 bp in length, consisting of telomerase- RNA-Binding Domain (RBD) and Reverse Transcriptase (RT) domains, 1024 amino acids, an isoelectric point of 9.58, and a relative molecular mass of 138.94 kD. Subcellular localization showed that was mainly localized in the nucleus and mitochondria. The results of the expression profile showed that was observed to respond to various stress conditions such as salt (100 mmol/L NaCl) and drought (20% PEG 6000). Furthermore, exogenous hormones IAA, ABA, and GA showed the potential to affect expression. Additionally, also responded to seed aging. Our results revealed a marginal but significant association between relative telomere length, expression, and seed germination percentage, suggesting that the length of telomeres was shortened, and expression of decreased with alfalfa seed aged. These results provide some evidence for the hypothesis of relative telomere length and/or TERT expression serving as biomarkers of seed aging. Although this finding is helpful to offer a new way to elucidate the molecular mechanism of vigor loss in alfalfa seed, further investigation is required to elucidate the molecular mechanism by which the regulates seed vigor.
种子老化一直被视为导致活力丧失的关键因素，因为种子萌发和幼苗生长延迟，这限制了干草产量。许多研究发现，端粒与非生物胁迫和种子活力密切相关。然而，端粒对非生物胁迫、种子活力的响应分子机制以及植物端粒稳态的维持机制仍不清楚。紫花苜蓿享有“牧草之王”的称号，是世界范围内种植的乳业重要蛋白质饲料。本研究旨在探讨紫花苜蓿在非生物胁迫和种子老化过程中的分子特征、系统发育关系及基因表达分析。在本研究中，从‘中苜1号’紫花苜蓿基因组中鉴定出 ，其编码序列（CDS）长度为3615 bp，由端粒酶RNA结合结构域（RBD）和逆转录酶（RT）结构域组成，含1024个氨基酸，等电点为9.58，相对分子质量为138.94 kD。亚细胞定位表明 主要定位于细胞核和线粒体。表达谱结果显示，观察到 对盐（100 mmol/L NaCl）和干旱（20% PEG 6000）等各种胁迫条件有响应。此外，外源激素IAA、ABA和GA显示出影响 表达的潜力。此外， 也对种子老化有响应。我们的结果揭示了相对端粒长度、 表达与种子发芽率之间存在微弱但显著的关联，表明随着苜蓿种子老化，端粒长度缩短， 表达降低。这些结果为相对端粒长度和/或TERT表达作为种子老化生物标志物的假说提供了一些证据。尽管这一发现有助于为阐明苜蓿种子活力丧失的分子机制提供新途径，但仍需要进一步研究以阐明 调节种子活力的分子机制。
