Alternative oxidase impacts ganoderic acid biosynthesis by regulating intracellular ROS levels in Ganoderma lucidum
Alternative oxidase impacts ganoderic acid biosynthesis by regulating intracellular ROS levels in Ganoderma lucidum
复制标题
替代氧化酶通过调节灵芝细胞内ROS水平影响灵芝酸生物合成
DOI：
10.1099/mic.0.000527
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发表时间：
2017-10-01
期刊：
影响因子：
2.8
通讯作者：
Zhao, Ming-Wen
中科院分区：
文献类型：
--
作者：
Shi, Deng-Ke;Zhu, Jing;Zhao, Ming-Wen
交替氧化酶（AOX）是线粒体呼吸电子传递途径的一个分支，其功能是维持电子通量和减轻活性氧（ROS）的产生。本研究在灵芝中发现了一个AOX同源基因。对G. lucidum基因全长1038个核苷酸，编码39.48kDa的蛋白质。利用RNA干扰技术研究AOX基因在G. lucidum）和两种沉默菌株（AOXi 6和AOXi 21），与WT相比，在旁路途径呼吸效率方面分别显示出约60%和50%的显著降低。突变株AOXi 6和AOXi 21中灵芝酸（GA）的含量分别比WT显著增加约42%和44%。在突变株AOXi 6和AOXi 21中，GA生物合成的中间代谢产物含量增加，相应基因的转录水平也升高。此外，与WT相比，菌株AOXi 6和AOXi 21中的细胞内ROS含量分别显著增加约1.75倍和1.93倍。此外，添加N-乙酰-L-半胱氨酸（NAC），ROS清除剂，显着降低细胞内的ROS含量和GA积累在AOX沉默菌株。这些结果表明AOX通过调节细胞内ROS水平来影响GA的生物合成。本研究揭示了AOX在G. lucidum。
The alternative oxidase (AOX), which forms a branch of the mitochondrial respiratory electron transport pathway, functions to sustain electron flux and alleviate reactive oxygen species (ROS) production. In this article, a homologous AOX gene was identified in Ganoderma lucidum. The coding sequence of the AOX gene in G. lucidum contains 1038 nucleotides and encodes a protein of 39.48 kDa. RNA interference (RNAi) was used to study the function of AOX in G. lucidum, and two silenced strains (AOXi6 and AOXi21) were obtained, showing significant decreases of approximately 60 and 50 %, respectively, in alternative pathway respiratory efficiency compared to WT. The content of ganoderic acid (GA) in the mutant strains AOXi6 and AOXi21 showed significant increases of approximately 42 and 44 %, respectively, compared to WT. Elevated contents of intermediate metabolites in GA biosynthesis and elevated transcription levels of corresponding genes were also observed in the mutant strains AOXi6 and AOXi21. In addition, the intracellular ROS content in strains AOXi6 and AOXi21 was significantly increased, by approximately 1.75- and 1.93-fold, respectively, compared with WT. Furthermore, adding N-acetyl-L-cysteine (NAC), a ROS scavenger, significantly depressed the intracellular ROS content and GA accumulation in AOX-silenced strains. These results indicate that AOX affects GA biosynthesis by regulating intracellular ROS levels. Our research revealed the important role of AOX in the secondary metabolism of G. lucidum.