PDF(Pubmed)
Abstract：
Soil alkalization is an important environmental factor limiting crop production. Despite the importance of root secretion in the response of plants to alkali stress, the regulatory mechanism is unclear. In this study, we applied a widely targeted metabolomics approach using a local MS/MS data library constructed with authentic standards to identify and quantify root exudates of wheat under salt and alkali stresses. The regulatory mechanism of root secretion in alkali-stressed wheat plants was analyzed by determining transcriptional and metabolic responses. Our primary focus was alkali stress-induced secreted metabolites (AISMs) that showed a higher secretion rate in alkali-stressed plants than in control and salt-stressed plants. This secretion was mainly induced by high-pH stress. We discovered 55 AISMs containing -COOH groups, including 23 fatty acids, 4 amino acids, 1 amino acid derivative, 7 dipeptides, 5 organic acids, 9 phenolic acids, and 6 others. In the roots, we also discovered 29 metabolites with higher levels under alkali stress than under control and salt stress conditions, including 2 fatty acids, 3 amino acid derivatives, 1 dipeptide, 2 organic acids, and 11 phenolic acids. These alkali stress-induced accumulated carboxylic acids may support continuous root secretion during the response of wheat plants to alkali stress. In the roots, RNAseq analysis indicated that 5 6-phosphofructokinase (glycolysis rate-limiting enzyme) genes, 16 key fatty acid synthesis genes, and 122 phenolic acid synthesis genes have higher expression levels under alkali stress than under control and salt stress conditions. We propose that the secretion of multiple types of metabolites with a -COOH group is an important pH regulation strategy for alkali-stressed wheat plants. Enhanced glycolysis, fatty acid synthesis, and phenolic acid synthesis will provide more energy and substrates for root secretion during the response of wheat to alkali stress.
摘要：
土壤碱化是限制作物生产的重要环境因子。尽管根系分泌在植物对碱胁迫的反应中很重要，监管机制尚不清楚。在这项研究中,我们应用了一种广泛有针对性的代谢组学方法，该方法使用了由真实标准构建的本地MS/MS数据库来识别和定量盐和碱胁迫下小麦的根系分泌物。通过确定转录和代谢反应，分析了碱胁迫小麦植株根系分泌的调节机制。我们的主要重点是碱胁迫诱导的分泌代谢物（AISM），其在碱胁迫植物中的分泌率高于对照和盐胁迫植物。这种分泌主要是由高pH胁迫诱导的。我们发现了55个含有-COOH基团的AISM，包括23种脂肪酸，4个氨基酸，1个氨基酸衍生物，7二肽，5有机酸，9酚酸，和其他6个。在根中，我们还发现了29种代谢物在碱胁迫下的水平高于对照和盐胁迫条件下的水平，包括2种脂肪酸，3氨基酸衍生物，1二肽，2有机酸，和11种酚酸。这些碱胁迫诱导的积累的羧酸可以在小麦植物对碱胁迫的响应期间支持连续的根部分泌。在根中，RNAseq分析表明，56-磷酸果糖激酶（糖酵解限速酶）基因，16个关键脂肪酸合成基因，和122个酚酸合成基因在碱胁迫下的表达水平高于对照和盐胁迫条件下的表达水平。我们建议分泌具有-COOH基团的多种类型的代谢物是碱胁迫小麦植物的重要pH调节策略。增强糖酵解，脂肪酸合成，在小麦对碱胁迫的响应过程中，酚酸合成将为根系分泌提供更多的能量和底物。
