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Dynamic analysis of lignin biosynthesis by stable-isotope tracer method

稳定同位素示踪法动态分析木质素生物合成

基本信息

批准号：
14360097
负责人：
FUKUSHIMA Kazuhiko
金额：
$ 9.41万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14360097/
关键词：
coniferin coniferyl alcohol coniferaldehyde lignin Ginkgo biosynthesis sinapic acid hardwood コニフェリアルアルコール

项目摘要

Although recent molecular biological studies have led to the general idea of a "metabolic grid" for lignin biosynthesis, leading to novel findings in the study of lignin, many problems remain. One of these problems is the monolignol supply mechanism. To examine the storage and supply of monolignol in lignifying xylem tissue, we focused on coniferin (coniferyl alcohol glucoside) and coniferaldehyde glucoside. Tracer experiments using labeled glucosides showed that both glucosides were efficiently incorporated into lignin, and that a portion of the coniferin administered passed through an aldehyde form before polymerization into lignin. This suggests that there is another pathway by which coniferin joins the monolignol biosynthesis pathway, in addition to the pathway consisting of de-glucosylation catalyzed by β-glucosidase. Interestingly, syringyl units were rarely synthesized from coniferin via the cinnamyl alcohol stage, whereas numerous syringyl units were synthesized from coniferaldehyde glucoside. Based on these results, we propose a possible pathway in which some of the stored coniferin is oxidized to coniferaldehyde glucoside and de-glucosylation generates coniferaldehyde, which flows into the monolignol pathway.

尽管最近的分子生物学研究已经形成了木质素生物合成的代谢网格的总体概念，并在木质素的研究中取得了新的发现，但仍然存在许多问题。其中一个问题是单醇供应机制。为了检测木质化木质部组织中单甘醇的储存和供应，我们重点研究了针叶苷(针叶醇葡萄糖苷)和针叶醛葡萄糖苷。使用标记糖苷的示踪实验表明，这两种糖苷都能有效地结合到木质素中，并且在聚合成木质素之前，给药的部分针叶树苷通过了醛的形式。这表明，除了由β-葡萄糖苷酶催化的脱糖途径外，还存在另一条途径，使松柏苷加入单甘醇生物合成途径。有趣的是，很少从松柏苷通过肉桂醇阶段合成紫丁香基单元，而许多紫丁香基单元是由针叶醛葡萄糖苷合成的。基于这些结果，我们提出了一种可能的途径，在这个途径中，储存的部分松柏苷被氧化成针叶醛葡萄糖苷，脱糖作用产生针叶醛，然后进入单甘醇途径。