METABOLIC FATE OF SECONDARY METABOLITES : INVOLVEMENT OF CELL WALLS

次级代谢物的代谢命运：细胞壁的参与

基本信息

批准号：
17580095
负责人：
ISHIHARA Atsushi
金额：
$ 2.37万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

The metabolic fates of secondary metabolites were investigated in gramineous plants, oats, and a model plant Arabidopsis thaliana.In oats, it has been demonstrated that their phytoalesxins, avenanthramides, are incorporated into cell walls. lb know the incorporation processes in detail, the metabolites that are derived from avenanthramides were investigated. The avenanthramide metabolites that are genrerated by the action of peroxidase were found to be present in oat leaves. The analysis of their chemical structures revealed that they are dehydrodimers of avenanthramides. The spectroscopic analysis revealed that they have unique carbon skeletons that have not been found in natural products. These compounds are considered to be units for the incorporation of avenanthramides into cell walls.In Arabidopsis thaliana, indole-3-carboxylic acid (ICA) has been indicated to bound to the cell walls. We found that the amount of ICA increases in the leaves infected by A. brassicicola. The biosynthetic pathway of ICA was analyzed by using stable isotope labeled putative precursors and mutants that exhibit modified tryptophan metabolism. First, Arabidopsis leaves were fed with labeled tryptophan and the conidia of A. brassicicola were inoculated. The leaves were extracted with methanol and the incorporation of tryptophan into ICA was analyzed by LC-MS/MS. The labeled tryptophan was effectively incorporated into ICA, indicating de novo synthesis of ICA in the infected leaves. Next, we analyzed ICA contents in multiple lines that have altered tryptophan metabolism. The increase of the amount of ICA in the cell walls was found in pad 3 mutant line. pad 3 line larks the accumulation of indolic phytoalexin, camalexin. Thus, this finding strongly suggests that ICA is not directly derived from camalexin, and that the biosynthetic pathway of ICA is shared by the pathway for camalexin.

在燕麦片中研究了二次代谢产物的代谢命运。在燕麦中，已经证明他们的植物乳糖素（avenananththarmides）被掺入细胞壁中。 LB知道详细的掺入过程，研究了源自avenantharmides的代谢产物。通过过氧化物酶的作用，存在于燕麦叶中，这些代谢产物被发现存在于燕麦叶中。对它们的化学结构的分析表明，它们是Avenantharmides的脱氢二聚体。光谱分析表明，它们具有在天然产物中未发现的独特碳骨架。这些化合物被认为是将avenanththamides掺入细胞壁的单位。在拟南芥中，吲哚 - 3-羧酸（ICA）已指示与细胞壁结合。我们发现，ICA的量增加了由A. brassicicola感染的叶子。通过使用稳定的同位素标记为假定的前体和突变体，表现出改良的色氨酸代谢，分析了ICA的生物合成途径。首先，拟南芥叶子被标记为色氨酸，并接种了甘蓝的分生孢子。用甲醇提取叶子，并通过LC-MS/MS分析色氨酸掺入ICA。标记的色氨酸有效地掺入ICA中，表明在感染叶片中从头合成ICA。接下来，我们分析了有多种色氨酸代谢的多个系中的ICA含量。在PAD 3突变线中发现了细胞壁中ICA量的增加。 PAD 3线lard lars呈吲哚二甲甲状腺素的积累，Camalexin。因此，这一发现强烈表明ICA不是直接衍生自Camalexin的，并且ICA的生物合成途径由Camalexin的途径共享。