BACKGROUND Fungi are constantly exposed to nitrogen limiting environments, and thus the efficient regulation of nitrogen metabolism is essential for their survival, growth, development and pathogenicity. To understand how the rice blast pathogen Magnaporthe oryzae copes with limited nitrogen availability, a global proteome analysis under nitrogen supplemented and nitrogen starved conditions was completed. METHODS M. oryzae strain 70-15 was cultivated in liquid minimal media and transferred to media with nitrate or without a nitrogen source. Proteins were isolated and subjected to unfractionated gel-free based liquid chromatography-tandem mass spectrometry (LC-MS/MS). The subcellular localization and function of the identified proteins were predicted using bioinformatics tools. RESULTS A total of 5498 M. oryzae proteins were identified. Comparative analysis of protein expression showed 363 proteins and 266 proteins significantly induced or uniquely expressed under nitrogen starved or nitrogen supplemented conditions, respectively. A functional analysis of differentially expressed proteins revealed that during nitrogen starvation nitrogen catabolite repression, melanin biosynthesis, protein degradation and protein translation pathways underwent extensive alterations. In addition, nitrogen starvation induced accumulation of various extracellular proteins including small extracellular proteins consistent with observations of a link between nitrogen starvation and the development of pathogenicity in M. oryzae. CONCLUSION The results from this study provide a comprehensive understanding of fungal responses to nitrogen availability.

中文翻译：

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稻瘟病菌中氮补充和饥饿条件之间的比较蛋白质组学分析。

背景技术真菌不断暴露于限氮环境中，因此对氮代谢的有效调控对其生存、生长、发育和致病性至关重要。为了了解稻瘟病病原体稻瘟病菌如何应对有限的氮供应，完成了在氮补充和氮缺乏条件下的全球蛋白质组分析。方法 M. oryzae 菌株 70-15 在液体基本培养基中培养，然后转移到含硝酸盐或不含氮源的培养基中。分离蛋白质并对其进行未分级的无凝胶液相色谱-串联质谱 (LC-MS/MS)。使用生物信息学工具预测所鉴定蛋白质的亚细胞定位和功能。结果 共鉴定出 5498 种米分枝杆菌蛋白。蛋白质表达的比较分析表明，363 种蛋白质和 266 种蛋白质分别在氮饥饿或氮补充条件下显着诱导或独特表达。对差异表达蛋白质的功能分析表明，在氮饥饿期间，氮分解代谢物抑制、黑色素生物合成、蛋白质降解和蛋白质翻译途径经历了广泛的改变。此外，氮饥饿诱导各种细胞外蛋白的积累，包括小的细胞外蛋白，这与观察到的氮饥饿与米分枝杆菌致病性发展之间的联系一致。结论 本研究的结果提供了对真菌对氮有效性反应的全面理解。