Accumulation of Isochorismate-derived 2,3-Dihydroxybenzoic 3-O-β-D-Xyloside in Arabidopsis Resistance to Pathogens and Ageing of Leaves
Accumulation of Isochorismate-derived 2,3-Dihydroxybenzoic 3-O-β-D-Xyloside in Arabidopsis Resistance to Pathogens and Ageing of Leaves
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DOI：
10.1074/jbc.m109.092569
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发表时间：
2010-08-13
影响因子：
4.8
通讯作者：
Parker, Jane E.
中科院分区：
文献类型：
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作者：
Bartsch, Michael;Bednarek, Pawel;Parker, Jane E.
一个复杂的激素信号网络调节着植物的发育和对生物和非生物胁迫的反应。水杨酸（SA）来源于莽草酸/异氯酸途径，是抵抗生物营养病原体的关键激素。一些SA衍生物和相关的修饰酶已经被鉴定出来，并与苯甲酸中间体或生物活性分子的储存和通道有关。然而，sa相关代谢物的作用范围和方式仍然难以捉摸。在拟南芥中，增强的疾病易感性1 （EDS1）促进了sa依赖和sa独立的对病原体的抗性反应。在这里，我们利用拟南芥野生型和eds1突变体叶片提取物的代谢物分析来鉴定除SA以外的分子，这些分子的积累需要eds1信号传导。核磁共振和质谱分析表明，2,3-二羟基苯甲酸（2,3- dhba）是一种源自异choris酸的次生代谢物，其积累依赖于植物抗性反应和衰老过程中的EDS1。2,3- dhba主要以木糖缀合形式存在（2-羟基-3- β - o - d -xylopyranosyloxy苯甲酸），在结构上不同于已知的sa -葡萄糖缀合物。对各种拟南芥突变体DHBA积累谱的分析表明，EDS1控制下的酶促2,3-DHBA合成途径。我们提出EDS1通路的组分指导2,3- dhba的产生或稳定，作为一种潜在的生物活性分子，它作为木糖偶联物被隔离。
An intricate network of hormone signals regulates plant development and responses to biotic and abiotic stress. Salicylic acid (SA), derived from the shikimate/isochorismate pathway, is a key hormone in resistance to biotrophic pathogens. Several SA derivatives and associated modifying enzymes have been identified and implicated in the storage and channeling of benzoic acid intermediates or as bioactive molecules. However, the range and modes of action of SA-related metabolites remain elusive. In Arabidopsis, Enhanced Disease Susceptibility 1 (EDS1) promotes SA-dependent and SA-independent responses in resistance against pathogens. Here, we used metabolite profiling of Arabidopsis wild type and eds1 mutant leaf extracts to identify molecules, other than SA, whose accumulation requires EDS1 signaling. Nuclear magnetic resonance and mass spectrometry of isolated and purified compounds revealed 2,3-dihydroxybenzoic acid (2,3-DHBA) as an isochorismate-derived secondary metabolite whose accumulation depends on EDS1 in resistance responses and during ageing of plants. 2,3-DHBA exists predominantly as a xylose-conjugated form (2-hydroxy-3-beta-O-D-xylopyranosyloxy benzoic acid) that is structurally distinct from known SA-glucose conjugates. Analysis of DHBA accumulation profiles in various Arabidopsis mutants suggests an enzymatic route to 2,3-DHBA synthesis that is under the control of EDS1. We propose that components of the EDS1 pathway direct the generation or stabilization of 2,3-DHBA, which as a potentially bioactive molecule is sequestered as a xylose conjugate.