Functional analysis of the role of glutathione peroxidase (GPx) in the ROS signaling pathway, hyphal branching and the regulation of ganoderic acid biosynthesis in Ganoderma lucidum
Functional analysis of the role of glutathione peroxidase (GPx) in the ROS signaling pathway, hyphal branching and the regulation of ganoderic acid biosynthesis in Ganoderma lucidum
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DOI：
10.1016/j.fgb.2015.07.008
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发表时间：
2015-09-01
影响因子：
3
通讯作者：
Zhao, Mingwen
中科院分区：
文献类型：
--
作者：
Li, Chenyang;Shi, Liang;Zhao, Mingwen
灵芝是我国传统中药的代表性成分，具有广泛的药用价值。虽然大量的研究集中在药理机制上，但很少有研究探讨该物种的基本生物学特性，限制了这一重要蘑菇的进一步开发和应用。由于这种蘑菇能够减少和解毒各种代谢途径产生的化合物，谷胱甘肽过氧化物酶（GPx）是相对于ROS最重要的抗氧化酶之一。虽然在动物和植物中的研究表明GPx的许多重要的生理功能，有很少的系统研究，这种酶在真菌中的作用，特别是在大型的担子菌。在本研究中，我们克隆了GPx基因，并通过使用RNA干扰下调GPx基因表达来创建GPx沉默菌株。结果表明，GPx对灵芝菌丝体的分枝、胞内H2 O2含量、抗氧化胁迫能力、胞内Ca ~（2+）含量和灵芝酸的生物合成具有重要的调控作用。进一步的机制研究表明，GPx是由细胞内H2 O2水平的调节，并建议之间发生串扰GPx和细胞内H2 O2。此外，获得的证据表明，GPx调节菌丝分支通过ROS可能发生独立的胞质Ca 2+含量。进一步的机制研究还表明，GPx通过ROS对灵芝酸合成的影响是由胞质Ca 2+含量调节的。综上所述，这些发现表明ROS对真菌的生长、发育和次生代谢具有复杂的影响，GPx具有重要的功能。本研究提供了一个很好的框架，以确定GPx功能，并强调了这种酶在ROS调节的作用。(C)2015 Elsevier Inc. All rights reserved.
Ganoderma lucidum, a hallmark of traditional Chinese medicine, has been widely used as a pharmacologically active compound. Although numerous research studies have focused on the pharmacological mechanism, fewer studies have explored the basic biological features of this species, restricting the further development and application of this important mushroom. Because of the ability of this mushroom to reduce and detoxify the compounds produced by various metabolic pathways, glutathione peroxidase (GPx) is one of the most important antioxidant enzymes with respect to ROS. Although studies in both animals and plants have suggested many important physiological functions of GPx, there are few systematic research studies concerning the role of this enzyme in fungi, particularly in large basidiomycetes. In the present study, we cloned the GPx gene and created GPx-silenced strains by the down-regulation of GPx gene expression using RNA interference. The results indicated an essential role for GPx in controlling the intracellular H2O2 content, hyphal branching, antioxidant stress tolerance, cytosolic Ca2+ content and ganoderic acid biosynthesis. Further mechanistic investigation revealed that GPx is regulated by intracellular H2O2 levels and suggested that crosstalk occurs between GPx and intracellular H2O2. Moreover, evidence was obtained indicating that GPx regulation of hyphal branching via ROS might occur independently of the cytosolic Ca2+ content. Further mechanistic investigation also revealed that the effects of GPx on ganoderic acid synthesis via ROS are regulated by the cytosolic Ca2+ content. Taken together, these findings indicate that ROS have a complex influence on growth, development and secondary metabolism in fungi and that GPx serves an important function. The present study provides an excellent framework to identify GPx functions and highlights a role for this enzyme in ROS regulation. (C) 2015 Elsevier Inc. All rights reserved.