Department of Plant Ecophysiology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, 90 237, Poland.
Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Faculté des Sciences, Université libre de Bruxelles, Brussels, 1050, Belgium.
BMC Plant Biol. 2024 Jul 25;24(1):707. doi: 10.1186/s12870-024-05434-5.
Natural populations of Arabidopsis thaliana exhibit phenotypic variations in specific environments and growth conditions. However, this variation has not been explored after seed osmopriming treatments. The natural variation in biomass production and root system architecture (RSA) was investigated across the Arabidopsis thaliana core collection in response to the pre-sawing seed treatments by osmopriming, with and without melatonin (Mel). The goal was to identify and characterize physiologically contrasting ecotypes.
Variability in RSA parameters in response to PEG-6000 seed osmopriming with and without Mel was observed across Arabidopsis thaliana ecotypes with especially positive impact of Mel addition under both control and 100 mM NaCl stress conditions. Two ecotypes, Can-0 and Kn-0, exhibited contrasted root phenotypes: seed osmopriming with and without Mel reduced the root growth of Can-0 plants while enhancing it in Kn-0 ones under both control and salt stress conditions. To understand the stress responses in these two ecotypes, main stress markers as well as physiological analyses were assessed in shoots and roots. Although the effect of Mel addition was evident in both ecotypes, its protective effect was more pronounced in Kn-0. Antioxidant enzymes were induced by osmopriming with Mel in both ecotypes, but Kn-0 was characterized by a higher responsiveness, especially in the activities of peroxidases in roots. Kn-0 plants experienced lower oxidative stress, and salt-induced ROS accumulation was reduced by osmopriming with Mel. In contrast, Can-0 exhibited lower enzyme activities but the accumulation of proline in its organs was particularly high. In both ecotypes, a greater response of antioxidant enzymes and proline accumulation was observed compared to mechanisms involving the reduction of Na content and prevention of K efflux.
In contrast to Can-0, Kn-0 plants grown from seeds osmoprimed with and without Mel displayed a lower root sensitivity to NaCl-induced oxidative stress. The opposite root growth patterns, enhanced by osmopriming treatments might result from different protective mechanisms employed by these two ecotypes which in turn result from adaptive strategies proper to specific habitats from which Can-0 and Kn-0 originate. The isolation of contrasting phenotypes paves the way for the identification of genetic factors affecting osmopriming efficiency.
拟南芥自然种群在特定环境和生长条件下表现出表型变异。然而，这种变异在种子渗调处理后尚未得到探索。本研究通过对渗调处理前后的种子进行 PEG-6000 渗调处理，结合是否添加褪黑素（Mel），研究了拟南芥核心收集种在生物量产生和根系结构（RSA）方面的自然变异，旨在鉴定和表征具有生理差异的生态型。
在对照和 100mM NaCl 胁迫条件下，添加 Mel 对渗调处理前后拟南芥生态型的 RSA 参数变化有显著影响，特别是对 Mel 处理的生态型表现出更积极的影响。两个生态型，Can-0 和 Kn-0，表现出对比鲜明的根系表型：渗调处理前后添加 Mel 减少了 Can-0 植株的根生长，而在对照和盐胁迫条件下，却促进了 Kn-0 植株的根生长。为了了解这两个生态型的胁迫响应，对 shoot 和 root 中的主要胁迫标记物和生理分析进行了评估。尽管 Mel 添加的效果在两个生态型中都很明显，但在 Kn-0 中的保护作用更为明显。Mel 渗调处理诱导了 both ecotypes 的抗氧化酶，但 Kn-0 的反应性更高，尤其是根中的过氧化物酶活性。Kn-0 植物受到的氧化应激较小，Mel 渗调处理减少了盐诱导的 ROS 积累。相反，Can-0 表现出较低的酶活性，但器官中脯氨酸的积累特别高。与减少 Na 含量和防止 K 外流的机制相比，两个生态型都观察到了抗氧化酶和脯氨酸积累的更大反应。
与 Can-0 相比，用 Mel 渗调处理前后生长的 Kn-0 植物的根对 NaCl 诱导的氧化应激的敏感性较低。渗调处理增强的相反根生长模式可能源于这两个生态型采用的不同保护机制，而这些机制又源于 Can-0 和 Kn-0 各自特定生境的适应策略。对比表型的分离为鉴定影响渗调效率的遗传因素铺平了道路。
