Li Quansheng, Guo Rongrong, Li Aining, Wang Yonglin
State Key Laboratory of Efficient Production of Forest Resources, Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Haidian District, Beijing, 100083, China.
Stress Biol. 2025 May 8;5(1):33. doi: 10.1007/s44154-025-00223-y.
Poplar canker, caused by the fungus Cytospora chrysosperma, results in tremendous losses in poplar plantations in China. Although NADPH oxidases (NOXs) play important roles in the development and pathogenicity of several pathogenic fungi, their roles in C. chrysosperma remain unclear. In this study, we characterized three NOX genes (CcNox1, CcNox2, and CcNoxR) in C. chrysosperma. All three genes were highly upregulated during poplar branch infection, and deletion of any of them severely reduced virulence on poplar branches. Furthermore, deletion of either CcNox1 or CcNoxR resulted in a significant increase in endogenous reactive oxygen species production in hyphae, enhanced influx of Ca, the disruption of redox homeostasis and compromised mitochondrial integrity. Moreover, biosynthesis and secretion of a known virulence factor oxalic acid was obviously defective and exogenous oxalic acid supplementation rescued the virulence of the mutants. Taken together, our findings reveal that NOXs play important roles in redox homeostasis, mitochondrial integrity and pathogenicity in C. chrysosperma.
杨树溃疡病由真菌金黄壳囊孢菌（Cytospora chrysosperma）引起，给中国的杨树人工林造成了巨大损失。尽管NADPH氧化酶（NOXs）在几种致病真菌的发育和致病性中发挥着重要作用，但其在金黄壳囊孢菌中的作用仍不清楚。在本研究中，我们对金黄壳囊孢菌中的三个NOX基因（CcNox1、CcNox2和CcNoxR）进行了表征。这三个基因在杨树枝条感染过程中均高度上调，缺失其中任何一个都会严重降低对杨树枝条的毒力。此外，缺失CcNox1或CcNoxR会导致菌丝体内源活性氧生成显著增加、钙离子内流增强、氧化还原稳态破坏以及线粒体完整性受损。此外，已知的毒力因子草酸的生物合成和分泌明显存在缺陷，补充外源草酸可挽救突变体的毒力。综上所述，我们的研究结果表明，NOXs在金黄壳囊孢菌的氧化还原稳态、线粒体完整性和致病性中发挥着重要作用。
