Li Chenyang, Shi Liang, Chen Dongdong, Ren Ang, Gao Tan, Zhao Mingwen
College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing 210095, Jiangsu, People's Republic of China.
College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing 210095, Jiangsu, People's Republic of China.
Fungal Genet Biol. 2015 Sep;82:168-80. doi: 10.1016/j.fgb.2015.07.008. Epub 2015 Jul 26.
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 Ca(2+) 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 Ca(2+) content. Further mechanistic investigation also revealed that the effects of GPx on ganoderic acid synthesis via ROS are regulated by the cytosolic Ca(2+) 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.
灵芝是中药的标志性药材，已被广泛用作具有药理活性的化合物。尽管众多研究聚焦于其药理机制，但对该物种基本生物学特性的探索较少，这限制了这种重要蘑菇的进一步开发和应用。由于这种蘑菇能够还原并解毒各种代谢途径产生的化合物，谷胱甘肽过氧化物酶（GPx）是与活性氧（ROS）相关的最重要的抗氧化酶之一。尽管在动物和植物中的研究表明GPx具有许多重要的生理功能，但关于该酶在真菌，特别是大型担子菌中的作用，却鲜有系统的研究。在本研究中，我们克隆了GPx基因，并通过RNA干扰下调GPx基因表达创建了GPx沉默菌株。结果表明，GPx在控制细胞内过氧化氢含量、菌丝分支、抗氧化应激耐受性、胞质钙离子含量和灵芝酸生物合成中起着至关重要的作用。进一步的机制研究表明，GPx受细胞内过氧化氢水平的调节，并提示GPx与细胞内过氧化氢之间存在相互作用。此外，有证据表明，GPx通过ROS对菌丝分支的调节可能独立于胞质钙离子含量。进一步的机制研究还表明，GPx通过ROS对灵芝酸合成的影响受胞质钙离子含量的调节。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，且GPx发挥着重要作用。本研究为确定GPx的功能提供了一个良好的框架，并突出了该酶在ROS调节中的作用。
