植物生态学报 ›› 2006, Vol. 30 ›› Issue (3): 514-521.DOI: 10.17521/cjpe.2006.0068

• 研究论文 • 上一篇    下一篇

丛枝菌根真菌对植物次生代谢的影响

赵昕, 阎秀峰*()   

  1. 东北林业大学生命科学学院,哈尔滨 150040
  • 收稿日期:2005-04-04 接受日期:2005-07-22 出版日期:2005-04-04 发布日期:2006-05-30
  • 通讯作者: 阎秀峰
  • 作者简介:*E-mail: xfyan@mail.hl.cn.
  • 基金资助:
    黑龙江省杰出青年基金资助项目(JC-02-11)

EFFECTS OF ARBUSCULAR MYCORRHIZAL FUNGI ON PLANT SECONDARY METABOLISM

ZHAO Xin, YAN Xiu-Feng*()   

  1. College of Life Sciences, Northeast Forestry University, Harbin 150040, China
  • Received:2005-04-04 Accepted:2005-07-22 Online:2005-04-04 Published:2006-05-30
  • Contact: YAN Xiu-Feng

摘要:

丛枝菌根(AM)是自然界中分布最为广泛、最为重要的一类菌根,许多研究已经观察到丛枝菌根真菌与植物次生代谢的相关性,丛枝菌根真菌能够直接或间接地影响植物的次生代谢过程。植物的次生代谢产物主要分为萜类物质、酚类物质和含氮化合物(主要是生物碱)三大类群,该文简要介绍了丛枝菌根真菌对这3类植物次生代谢产物的影响。丛枝菌根真菌与萜类物质代谢关系的研究比较细致和深入,有些工作已经从细胞及分子水平探讨其间的作用机制,如Blumenin、类胡萝卜素等。丛枝菌根真菌与酚类物质代谢关系的研究也比较深入,其中具有特殊功能的酚类物质——植保素、细胞壁酚酸、类黄酮/异类黄酮等倍受关注。目前有关丛枝菌根真菌与生物碱关系的研究相对较少,不过现有的研究表明,菌根的形成有助于生物碱积累。

关键词: 丛枝菌根, 植物次生代谢, 萜类, 酚类, 生物碱

Abstract:

Mycorrhizal fungi form the most important mutualistic symbioses on earth with plants. The most prevalent type of mycorrhizal fungi are the arbuscular mycorrhizal (AM) fungi. Much research has shown that the development of AM fungi is correlated with plant secondary metabolism. AM fungi can directly or indirectly affect plant secondary metabolic processes. Secondary metabolites are classified into 3 groups, terpenoids, phenolics and alkaloids. In this paper, we summarize the effects of AM fungi on the 3 groups of secondary metabolites.

The relationship between terpenoids and AM fungi have been well studied, and some research has explored interactive mechanisms at the molecular level. Blumenin was first isolated and identified from mycorrhizal cereals, and its biosynthesis has been proven via the Glyceraldehyde 3-phosphate/ pyruvate pathway (MEP) by an isotopic labeling method. Since then, the accumulation of blumenin induced by AM fungi and differences in blumenin levels among different kinds of AM fungi have been observed. Studies on 1-deoxy-D-xylulose-5-phosphate synthase (DXS) and 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR), two key enzymes in the biosynthesis of carotenoid metabolism via the MEP pathway, have found to increase the transcription of DXS and DXR in plants with AM fungi. Moreover it was temporarily and spatially correlated with the accumulation of apocarotenoids. Subsequently, two genes were identified: TC78589 encoding DXS2 which is highly expressed in roots inoculated with AM fungi, and TC77051 encoding mevalonate disphosphate decarboxylase, which is catalysed in the synthesis of terpenoids in the mevalonate pathway. Although both genes separately encode enzymes in different pathways, an enhancement of carotenoid biosynthesis has been observed.

The interaction between phenolic compounds (such as phytoalexin, wall-bound phenol, flavonoids, isoflavonoids and their derivatives) and AM fungi also has been investigated intensively. It has been shown that some flavonoids stimulated the spore germination and hyphal growth of AM fungi, and the contents of flavonoids increased before the infection of AM fungi. Therefore some investigators hypothesized that flavonoids were a signal compound during the formation of AM fungi. Afterward, increased levels of flavonoids were found after the formation of AM fungi which was related to specific species of AM fungi. In addition, some experiments have indicated that the activity of peroxidase (POD), phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) were significantly enhanced in AM plants. In phenylpropamoid metabolism, there are two different signaling pathways in the accumulation of secondary metabolites induced by the mycorrhizal fungus: one is through the induction of PAL and chalcone synthase (CHS), and the other is through the suppression of isoflavone reductase (IFR).

Although little research seldom has examined the relationship between alkaloids and AM fungi, a recent study has shown that the formation of AM is beneficial to the accumulation of alkaloids. This study also showed the species specificity in AM affected biosynthesis of alkaloids.

Key words: Arbuscular mycorrhizal (AM), Plant secondary metabolism, Terpenoids, Phenolics, Alkaloids