Institute of Plant Nutrition and Soil Science, Christian Albrechts University Kiel, Hermann-Rodewald Str. 2, D-24118 Kiel, Germany.
Department of Proteome and Metabolome Research, Faculty of Biology, Bielefeld University, Postfach 100131, D-33501 Bielefeld, Germany.
Plant Physiol Biochem. 2015 Jul;92:19-29. doi: 10.1016/j.plaphy.2015.04.008. Epub 2015 Apr 11.
Salt stress impairs global agricultural crop production by reducing vegetative growth and yield. Despite this importance, a number of gaps exist in our knowledge about very early metabolic responses that ensue minutes after plants experience salt stress. Surprisingly, this early phase remains almost as a black box. Therefore, systematic studies focussing on very early plant physiological responses to salt stress (in this case NaCl) may enhance our understanding on strategies to develop crop plants with a better performance under saline conditions. In the present study, hydroponically grown Vicia faba L. plants were exposed to 90 min of NaCl stress, whereby every 15 min samples were taken for analyzing short-term physiologic responses. Gas chromatography-mass spectrometry-based metabolite profiles were analysed by calculating a principal component analysis followed by multiple contrast tests. Follow-up experiments were run to analyze downstream effects of the metabolic changes on the physiological level. The novelty of this study is the demonstration of complex stress-induced metabolic changes at the very beginning of a moderate salt stress in V. faba, information that are very scant for this early stage. This study reports for the first that the proline analogue trans-4-hydroxy-L-proline, known to inhibit cell elongation, was increasingly synthesized after NaCl-stress initiation. Leaf metabolites associated with the generation or scavenging of reactive oxygen species (ROS) were affected in leaves that showed a synchronized increase in ROS formation. A reduced glutamine synthetase activity indicated that disturbances in the nitrogen assimilation occur earlier than it was previously thought under salt stress.
盐胁迫通过降低营养生长和产量来损害全球农业作物生产。尽管这一点很重要，但我们对植物经历盐胁迫后几分钟内发生的非常早期的代谢反应的了解还存在一些空白。令人惊讶的是，这个早期阶段几乎还是一个黑盒子。因此，系统地研究植物对盐胁迫（在这种情况下是 NaCl）的非常早期的生理反应可能会增强我们对开发在盐渍条件下表现更好的作物的理解。在本研究中，水培生长的蚕豆（Vicia faba L.）植物暴露于 90 分钟的 NaCl 胁迫下，每隔 15 分钟取一次样本以分析短期生理反应。通过计算主成分分析和多对比检验分析基于气相色谱-质谱的代谢物图谱。进行后续实验以分析代谢变化对生理水平的下游影响。这项研究的新颖之处在于，在中度盐胁迫的早期，在蚕豆中展示了复杂的应激诱导代谢变化，而这方面的信息非常有限。本研究首次报道，脯氨酸类似物反式-4-羟基-L-脯氨酸，已知抑制细胞伸长，在 NaCl 胁迫开始后合成增加。与活性氧（ROS）生成或清除相关的叶片代谢物在表现出 ROS 同步增加的叶片中受到影响。谷氨酰胺合成酶活性降低表明，氮同化的干扰比以前认为的在盐胁迫下更早发生。
