The fungus Verticillium dahliae causes vascular wilt disease on hundreds of plant species. Homologs of the bZIP transcription factor Atf1 are required for virulence in most pathogenic fungi, but the molecular basis for their involvement is largely unknown. We performed targeted gene deletion, expression analysis, biochemistry and pathogenicity assays to demonstrate that VdAtf1 governs pathogenesis via the regulation of nitrosative resistance and nitrogen metabolism in V. dahliae. VdAtf1 controls pathogenesis via the regulation of nitric oxide (NO) resistance and inorganic nitrogen metabolism rather than oxidative resistance and is important for penetration peg formation in V. dahliae. VdAtf1 affects ammonium and nitrate assimilation in response to various nitrogen sources. VdAtf1 may be involved in regulating the expression of VdNut1. VdAtf1 responds to NO stress by strengthening the fungal cell wall, and by causing over-accumulation of methylglyoxal and glycerol, which in turn impacts NO detoxification. We also verified that the VdAtf1 ortholog in Fusarium graminearum mediates nitrogen metabolism, suggesting conservation of this function in related plant pathogenic fungi. Our findings revealed new functions of VdAtf1 in pathogenesis, response to nitrosative stress and nitrogen metabolism in V. dahliae. The results provide novel insights into the regulatory mechanisms of the transcription factor VdAtf1 in virulence.

中文翻译：

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bZIP转录因子VdAtf1通过介导黄萎病菌中的氮代谢来调节毒力。

黄萎病真菌对数百种植物引起维管束枯萎病。bZIP转录因子Atf1的同系物是大多数致病真菌中毒力所必需的，但其参与的分子基础在很大程度上尚不清楚。我们进行了有针对性的基因删除，表达分析，生化和致病性分析，以证明VdAtf1通过调节大丽花亚硝化抗性和氮代谢来控制发病机理。VdAtf1通过调节一氧化氮（NO）抵抗力和无机氮代谢而不是氧化抵抗力来控制发病机理，并且对于大隐孢子虫的穿透钉形成非常重要。VdAtf1会响应各种氮源而影响铵和硝酸盐的同化作用。VdAtf1可能参与调节VdNut1的表达。VdAtf1通过增强真菌细胞壁以及引起甲基乙二醛和甘油的过度积累而对NO胁迫作出反应，进而影响NO的解毒。我们还验证了禾谷镰刀菌中的VdAtf1直系同源物介导了氮的代谢，这表明该功能在相关的植物病原性真菌中具有保守性。我们的发现揭示了VdAtf1在大麦弧菌的发病机理，对亚硝化胁迫和氮代谢的响应中的新功能。该结果提供了对毒性中转录因子VdAtf1调控机制的新颖见解。提示该功能在相关植物病原真菌中得到保护。我们的发现揭示了VdAtf1在大麦弧菌的发病机理，对亚硝化胁迫和氮代谢的响应中的新功能。该结果提供了对毒性中转录因子VdAtf1调控机制的新颖见解。提示在相关的植物病原真菌中应保留此功能。我们的发现揭示了VdAtf1在大麦弧菌的发病机理，对亚硝化胁迫和氮代谢的响应中的新功能。该结果提供了对毒性中转录因子VdAtf1调控机制的新颖见解。