NADPH oxidases are enzymes that have been reported to generate reactive oxygen species (ROS) in animals, plants and many multicellular fungi in response to environmental stresses. Six genes of the NADPH oxidase complex components, including vvnoxa, vvnoxb, vvnoxr, vvbema, vvrac1 and vvcdc24, were identified based on the complete genomic sequence of the edible fungus Volvariella volvacea. The number of vvnoxa, vvrac1, vvbema and vvcdc24 transcripts fluctuated with ageing, and the gene expression patterns of vvnoxa, vvrac1 and vvbema were significantly positively correlated. However, the expression of vvnoxb and vvnoxr showed no significant difference during ageing. In hyphae subjected to mechanical injury stress, both O2- and H2O2 concentrations were increased. The expression of vvnoxa, vvrac1, vvbema and vvcdc24 was substantially upregulated, but vvnoxb and vvnoxr showed no response to mechanical injury stress at the transcriptional level. Additionally, the transcription of vvnoxa, vvrac1, vvbema and vvcdc24 could be repressed when the intracellular ROS were eliminated by diphenyleneiodonium (DPI) chloride and reduced glutathione (GSH) treatments. These results indicated a positive feedback loop involving NADPH oxidase and intracellular ROS, which might be the reason for the oxidative burst during injury stress.

中文翻译：

---

草菇中 NADPH 氧化酶及其响应菌丝老化和机械损伤的差异表达

NADPH 氧化酶是据报道在动物、植物和许多多细胞真菌中产生活性氧 (ROS) 以响应环境压力的酶。NADPH氧化酶复合物组分的六个基因，包括vvnoxa、vvnoxb、vvnoxr、vvbema、vvrac1和vvcdc24，基于食用菌Volvariella volvacea的完整基因组序列被鉴定。vvnoxa、vvrac1、vvbema和vvcdc24转录本的数量随着年龄的增长而波动，vvnoxa、vvrac1和vvbema的基因表达模式呈显着正相关。然而，vvnoxb 和 vvnoxr 的表达在衰老过程中没有显着差异。在受到机械损伤应力的菌丝中，O2- 和 H2O2 浓度均增加。vvnoxa、vvrac1、vvbema 和 vvcdc24 的表达显着上调，但 vvnoxb 和 vvnoxr 在转录水平上对机械损伤应激没有反应。此外，当细胞内 ROS 通过氯化二亚苯基碘 (DPI) 和还原型谷胱甘肽 (GSH) 处理消除时，可以抑制 vvnoxa、vvrac1、vvbema 和 vvcdc24 的转录。这些结果表明涉及 NADPH 氧化酶和细胞内 ROS 的正反馈回路，这可能是损伤应激期间氧化爆发的原因。