Extensive secretion of phenolic acids and fatty acids facilitates rhizosphere pH regulation in halophyte Puccinellia tenuiflora under alkali stress
Extensive secretion of phenolic acids and fatty acids facilitates rhizosphere pH regulation in halophyte Puccinellia tenuiflora under alkali stress
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DOI：
10.1111/ppl.13678
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发表时间：
2022-03-01
影响因子：
6.4
通讯作者：
Yang, Chunwu
中科院分区：
文献类型：
--
作者：
Li, Hong;Xu, Chenyang;Yang, Chunwu
碱茅(Puccinellia Tenuiflora)是一种营养价值很高的饲草，是一种极耐碱的盐生植物，能在pH值为10-11的环境中存活。根分泌物被认为是植物耐碱的主要机制。在本研究中，我们应用了一种广泛靶向的代谢组学方法来鉴定和定量碱胁迫下的细花P.tenuiflora根分泌物。此外，我们还研究了盐(96 mM Na+，pH 6.8)和碱(96 mM Na+，pH 9.6)胁迫下细花毛白杨根系转录和代谢的变化，以揭示调控根系分泌的生物学过程。在对照条件下检测到493个根分泌物，在盐胁迫条件下检测到544个根分泌物，在碱胁迫条件下检测到607个根分泌物。盐胁迫植物和碱胁迫植物共享根分泌物，其中60个根分泌物是碱胁迫植物独有的。碱胁迫下根中56种酚酸、43种脂肪酸和9种有机酸的分泌速率明显快于对照和盐胁迫。碱胁迫促进了毛白杨根系中23种酚酸、5种有机酸和1种脂肪酸的积累。此外，转录分析表明，碱胁迫上调了黄花杨根部糖酵解和苯丙烷类化合物的生物合成途径。综上所述，碱胁迫下黄花杨大量分泌的酚酸和脂肪酸促进了根际pH的调节，从而使其具有较强的耐碱性。碱胁迫下细花毛白杨根系分泌物高度组织化。增强的糖酵解、苯丙烷类化合物的生物合成和有机酸的合成为碱胁迫下细花毛白杨的根系分泌过程提供了更多的还原能力和碳源。
Puccinellia tenuiflora is a forage grass with high nutritional value that is an extreme alkali-tolerant halophyte: it can survive at pH 10-11. Root secretion is perceived as a major plant alkali tolerance mechanism. In the present study, we applied a widely targeted metabolomic approach to identify and quantify the root exudates of P. tenuiflora under alkali stress. We also surveyed the transcriptional and metabolic profiling of P. tenuiflora roots under salt (96-mM Na+, pH 6.8) and alkali (96-mM Na+, pH 9.6) stresses to reveal the biological processes mediating root secretion. In P. tenuiflora plants, 493 root exudates were detected under control conditions, 544 root exudates under salt stress conditions, and 607 root exudates under alkali stress conditions. Salt-stressed plants and alkali-stressed plants shared 64 root exudates, and 60 root exudates were unique to alkali-stressed plants. The secretion rate of 56 phenolic acids, 43 fatty acids, and 9 organic acids was faster in alkali-stressed roots than in control and salt-stressed roots. In P. tenuiflora roots, alkali stress enhanced the accumulation of 23 phenolic acids, five organic acids, and only one fatty acid. In addition, transcriptomic analysis revealed that alkali stress upregulated glycolysis and phenylpropanoid biosynthesis pathways in P. tenuiflora roots. Taken together, extensive secretion of phenolic acids and fatty acids promotes rhizosphere pH regulation of P. tenuiflora under alkali stress, which contributes to its strong alkali tolerance. The root secretion of P. tenuiflora upon alkali stress is highly organized. Enhanced glycolysis, phenylpropanoid biosynthesis, and organic acid synthesis in the roots provide more reducing power and carbon source for the root secretion process of alkali-stressed P. tenuiflora.