Nutrient and stress factor 1 (Nsf1), a transcription factor containing the classical Cys2-His2 (C₂H₂) zinc finger motif, is expressed under non-fermentable carbon conditions and in response to salt stress in Saccharomyces cerevisiae. However, the role of Nsf1 in filamentous fungi is not well understood. In this study, the orthologue of Nsf1 was investigated in Fusarium graminearum (named FgNsf1), a causal agent of Fusarium head blight (FHB). The functions of FgNsf1 were evaluated by constructing a FgNSF1 deletion mutant, designated as ΔFgNsf1, and its functional complementation mutant ΔFgNsf1-C. Gene deletion experiments showed that the mycelial growth rate, asexual and sexual reproduction of ΔFgNsf1 were significantly reduced, but the pigment production of ΔFgNsf1 was remarkably increased compared with the PH-1 and ΔFgNsf1-C. In addition, the tolerance of ΔFgNsf1 to osmotic pressures, cell wall-damaging agents and oxidative stress increased significantly. Sensitivity tests to different fungicides revealed that ΔFgNsf1 exhibited increased sensitivity to carbendazim (MBC) and tebuconazole, and enhanced tolerance to fludioxonil and iprodione than PH-1 and ΔFgNsf1-C. The virulence of ΔFgNsf1 to wheat coleoptiles and flowering wheat heads were dramatically decreased, which was consistent with the decrease in the yield of deoxynivalenol (DON). All of these defects were restored by target gene complementation. These results indicated that FgNsf1 plays a crucial role in vegetative growth, asexual and sexual reproduction, stress responses, fungicide sensitivity, and full virulence in F. graminearum.

营养和应激因子 1 (Nsf1) 是一种包含经典 Cys2-His2 (C ₂ H ₂ ) 锌指基序的转录因子，在不可发酵的碳条件下表达并响应酿酒酵母中的盐胁迫。然而，Nsf1 在丝状真菌中的作用尚不清楚。在这项研究中，Nsf1 的直系同源物在禾谷镰刀菌（命名为 FgNsf1）中进行了研究，镰刀菌是枯萎病 (FHB) 的致病因子。FgNsf1 的功能通过构建FgNSF1缺失突变体（命名为 Δ FgNsf1）及其功能互补突变体 Δ FgNsf1-C 来评估。基因缺失实验表明，ΔFgNsf1的菌丝生长速率、无性繁殖和有性繁殖均显着降低，但与PH-1和ΔFgNsf1-C相比，ΔFgNsf1的色素产量显着增加。此外，Δ FgNsf1对渗透压、细胞壁损伤剂和氧化应激的耐受性显着增加。对不同杀菌剂的敏感性测试表明，Δ FgNsf1对多菌灵 (MBC) 和戊唑醇的敏感性增加，对氟菌腈和异菌脲的耐受性高于 PH-1 和 Δ FgNsf1-C。Δ FgNsf1的毒力小麦胚芽鞘和开花小麦头显着减少，这与脱氧雪腐镰刀菌烯醇 (DON) 产量的下降是一致的。所有这些缺陷都通过靶基因互补来恢复。这些结果表明 FgNsf1 在F. graminearum 的营养生长、无性繁殖和有性繁殖、应激反应、杀菌剂敏感性和完全毒力中起着至关重要的作用。