PDF(Pubmed)
Abstract：
BACKGROUND: 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.
RESULTS: 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.
CONCLUSIONS: 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.
RESULTS: 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.
CONCLUSIONS: 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.
摘要：
背景：拟南芥的自然种群在特定环境和生长条件下表现出表型变异。然而,种子渗透处理后，尚未探索这种变化。在整个拟南芥核心集合中研究了生物量生产和根系结构（RSA）的自然变化，以响应预锯切种子处理。有和没有褪黑激素（梅尔）。目的是鉴定和表征生理上相反的生态型。
结果：在有和没有Mel的情况下，在拟南芥生态型中观察到响应于PEG-6000种子渗透的RSA参数的变化，在对照和100mMNaCl胁迫条件下，添加Mel的影响尤其积极。两种生态型，Can-0和Kn-0表现出相反的根系表型：在控制和盐胁迫条件下，有和没有Mel的种子渗透会降低Can-0植物的根系生长，同时增强Kn-0植物的根系生长。为了了解这两种生态型的应激反应，在芽和根中评估了主要的胁迫标记以及生理分析。尽管在两种生态型中添加Mel的效果都很明显，其保护作用在Kn-0中更为明显。在两种生态型中，通过用Mel进行渗透来诱导抗氧化酶，但是Kn-0的特点是响应性较高，尤其是根中过氧化物酶的活性。Kn-0植物经历了较低的氧化应激，盐诱导的ROS积累通过Mel的渗透减少。相比之下,Can-0表现出较低的酶活性，但脯氨酸在其器官中的积累特别高。在这两种生态型中，与涉及降低Na含量和预防K外排的机制相比，观察到抗氧化酶和脯氨酸积累的反应更大。
结论：与Can-0相反，从有和没有Mel的种子中生长的Kn-0植物对NaCl诱导的氧化应激表现出较低的根系敏感性。相反的根系生长模式，通过渗透处理增强可能是由于这两种生态型采用的不同保护机制所致，而这又是由于适用于Can-0和Kn-0起源的特定栖息地的适应性策略所致。对比表型的分离为鉴定影响渗透效率的遗传因素铺平了道路。
结果：在有和没有Mel的情况下，在拟南芥生态型中观察到响应于PEG-6000种子渗透的RSA参数的变化，在对照和100mMNaCl胁迫条件下，添加Mel的影响尤其积极。两种生态型，Can-0和Kn-0表现出相反的根系表型：在控制和盐胁迫条件下，有和没有Mel的种子渗透会降低Can-0植物的根系生长，同时增强Kn-0植物的根系生长。为了了解这两种生态型的应激反应，在芽和根中评估了主要的胁迫标记以及生理分析。尽管在两种生态型中添加Mel的效果都很明显，其保护作用在Kn-0中更为明显。在两种生态型中，通过用Mel进行渗透来诱导抗氧化酶，但是Kn-0的特点是响应性较高，尤其是根中过氧化物酶的活性。Kn-0植物经历了较低的氧化应激，盐诱导的ROS积累通过Mel的渗透减少。相比之下,Can-0表现出较低的酶活性，但脯氨酸在其器官中的积累特别高。在这两种生态型中，与涉及降低Na含量和预防K外排的机制相比，观察到抗氧化酶和脯氨酸积累的反应更大。
结论：与Can-0相反，从有和没有Mel的种子中生长的Kn-0植物对NaCl诱导的氧化应激表现出较低的根系敏感性。相反的根系生长模式，通过渗透处理增强可能是由于这两种生态型采用的不同保护机制所致，而这又是由于适用于Can-0和Kn-0起源的特定栖息地的适应性策略所致。对比表型的分离为鉴定影响渗透效率的遗传因素铺平了道路。
