Zhang Haifeng, Li Bing, Fang Qin, Li Ying, Zheng Xiaobo, Zhang Zhengguang
Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing, 210095, China.
Mol Plant Pathol. 2016 Jan;17(1):108-19. doi: 10.1111/mpp.12267. Epub 2015 May 21.
Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins play critical and conserved roles in membrane fusion and vesicle transport of eukaryotic cells. Previous studies have shown that various homologues of SNARE proteins are also important in the infection of host plants by pathogenic fungi. Here, we report the characterization of a SNARE homologue, FgVam7, from Fusarium graminearum that causes head blight in wheat and barley worldwide. Phylogenetic analysis and domain comparison reveal that FgVam7 is homologous to Vam7 proteins of Saccharomyces cerevisiae (ScVam7), Magnaporthe oryzae (MoVam7) and several additional fungi by containing a PhoX homology (PX) domain and a SNARE domain. We show that FgVam7 plays a regulatory role in cellular differentiation and virulence in F. graminearum. Deletion of FgVAM7 significantly reduces vegetative growth, conidiation and conidial germination, sexual reproduction and virulence. The ΔFgvam7 mutant also exhibits a defect in vacuolar maintenance and delayed endocytosis. Moreover, the ΔFgvam7 mutant is insensitive to salt and osmotic stresses, and hypersensitive to cell wall stressors. Further characterization of FgVam7 domains indicate that the PX and SNARE domains are conserved in controlling Vam7 protein localization and function, respectively. Finally, FgVam7 has been shown to positively regulate the expression of several deoxynivalenol (DON) biosynthesis genes TRI5, TRI6 and TRI101, and DON production. Our studies provide evidence for SNARE proteins as an additional means of regulatory mechanisms that govern growth, differentiation and virulence of pathogenic fungi.
可溶性N - 乙基马来酰亚胺敏感因子附着蛋白受体（SNARE）蛋白在真核细胞的膜融合和囊泡运输中发挥着关键且保守的作用。先前的研究表明，SNARE蛋白的各种同源物在病原真菌感染宿主植物的过程中也很重要。在此，我们报道了一种来自禾谷镰刀菌的SNARE同源物FgVam7的特性，禾谷镰刀菌在全球范围内导致小麦和大麦的赤霉病。系统发育分析和结构域比较表明，FgVam7与酿酒酵母（ScVam7）、稻瘟病菌（MoVam7）以及其他几种真菌的Vam7蛋白同源，含有一个PhoX同源（PX）结构域和一个SNARE结构域。我们发现FgVam7在禾谷镰刀菌的细胞分化和毒力中起调节作用。缺失FgVAM7会显著降低其营养生长、分生孢子形成和分生孢子萌发、有性生殖以及毒力。ΔFgvam7突变体在液泡维持方面也存在缺陷，并且内吞作用延迟。此外，ΔFgvam7突变体对盐胁迫和渗透胁迫不敏感，而对细胞壁应激源敏感。对FgVam7结构域的进一步表征表明，PX结构域和SNARE结构域分别在控制Vam7蛋白定位和功能方面具有保守性。最后，已证明FgVam7正向调节几种脱氧雪腐镰刀菌烯醇（DON）生物合成基因TRI5、TRI6和TRI101的表达以及DON的产生。我们的研究为SNARE蛋白作为调控病原真菌生长、分化和毒力的额外调控机制提供了证据。
