Singer Stacy D, Lehmann Madeline, Zhang Zixuan, Subedi Udaya, Burton Hughes Kimberley, Lim Nathaniel Z-L, Ortega Polo Rodrigo, Chen Guanqun, Acharya Surya, Hannoufa Abdelali, Huan Tao
Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J 4B1, Canada.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
Plants (Basel). 2023 May 22;12(10):2059. doi: 10.3390/plants12102059.
Alfalfa ( L.) is a widely grown perennial leguminous forage crop with a number of positive attributes. However, despite its moderate ability to tolerate saline soils, which are increasing in prevalence worldwide, it suffers considerable yield declines under these growth conditions. While a general framework of the cascade of events involved in plant salinity response has been unraveled in recent years, many gaps remain in our understanding of the precise molecular mechanisms involved in this process, particularly in non-model yet economically important species such as alfalfa. Therefore, as a means of further elucidating salinity response mechanisms in this species, we carried out in-depth physiological assessments of cv. Beaver, as well as transcriptomic and untargeted metabolomic evaluations of leaf tissues, following extended exposure to salinity (grown for 3-4 weeks under saline treatment) and control conditions. In addition to the substantial growth and photosynthetic reductions observed under salinity treatment, we identified 1233 significant differentially expressed genes between growth conditions, as well as 60 annotated differentially accumulated metabolites. Taken together, our results suggest that changes to cell membranes and walls, cuticular and/or epicuticular waxes, osmoprotectant levels, antioxidant-related metabolic pathways, and the expression of genes encoding ion transporters, protective proteins, and transcription factors are likely involved in alfalfa's salinity response process. Although some of these alterations may contribute to alfalfa's modest salinity resilience, it is feasible that several may be disadvantageous in this context and could therefore provide valuable targets for the further improvement of tolerance to this stress in the future.
紫花苜蓿（Medicago sativa L.）是一种广泛种植的多年生豆科牧草作物，具有许多积极特性。然而，尽管它对盐渍土壤有一定的耐受能力，而盐渍土壤在全球范围内的分布日益广泛，但在这些生长条件下，它的产量仍会大幅下降。近年来，虽然参与植物盐胁迫响应的一系列事件的总体框架已被揭示，但我们对这一过程中涉及的精确分子机制的理解仍存在许多空白，特别是在像紫花苜蓿这样非模式但具有重要经济价值的物种中。因此，作为进一步阐明该物种盐胁迫响应机制的一种手段，我们对品种Beaver进行了深入的生理评估，以及在长时间暴露于盐胁迫（在盐处理下生长3 - 4周）和对照条件后对叶片组织进行转录组和非靶向代谢组评估。除了在盐处理下观察到的显著生长和光合速率降低外，我们还确定了两种生长条件之间有1233个显著差异表达的基因，以及60种注释的差异积累代谢物。综合来看，我们的结果表明，细胞膜和细胞壁、角质层和/或表皮蜡质、渗透保护剂水平、抗氧化相关代谢途径以及编码离子转运蛋白、保护蛋白和转录因子的基因表达的变化可能参与了紫花苜蓿的盐胁迫响应过程。虽然其中一些变化可能有助于紫花苜蓿对盐胁迫的适度耐受性，但在这种情况下，有几种变化可能是不利的，因此可能为未来进一步提高对这种胁迫的耐受性提供有价值的靶点。
