Li Bing, Mao Hui-Ying, Zhang Zhao-Yang, Chen Xi-Jun, Ouyang Shou-Qiang
College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China.
Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, China.
Front Microbiol. 2019 Nov 14;10:2658. doi: 10.3389/fmicb.2019.02658. eCollection 2019.
The soil-borne, asexual fungus f.sp. () is the causal agent of tomato wilt disease. Autophagy plays a crucial role in the development and virulence of . The endosomal system is highly dynamic and has been shown to be associated with conidiogenesis and pathogenicity. Rab GTPases and the regulators are highly conserved in regulating autophagy and endocytosis in most eukaryotes. Identification and characterization of additional Rab regulators in fungal pathogens should facilitate the understanding of the autophagy and endocytosis in different filamentous fungi. Here, we have identified and characterized the yeast homolog in . Targeted gene deletion showed that is important for growth, conidiation and virulence in . Cytological examination revealed that FolVps9 co-localized with FolVps21 (a marker of early endosome) and played a critical role in endocytosis and autophagosome degradation. Pull-down assays showed that FolVps9 interacted with FolVps21, which was also important for development and plant infection in . Yeast two-hybrid, bimolecular fluorescence complementation and co-immunoprecipitation assays revealed that FolVps9 specifically interacts with the GDP-bound form of FolVps21. Furthermore, a constitutively active form of FolVps21 (Q72L) was able to rescue defects of Δ and Δ mutants. In summary, our study provides solid evidence that FolVps9 acts as a FolVps21 guanine nucleotide exchange factor (GEFs) to modulate endocytosis and autophagy, thereby controlling vegetative growth, asexual development and pathogenicity in
土壤传播的无性真菌f.sp.（）是番茄枯萎病的病原体。自噬在该真菌的发育和毒力中起关键作用。内体系统高度动态，已被证明与分生孢子形成和致病性有关。Rab GTP酶及其调节因子在大多数真核生物中调节自噬和内吞作用时高度保守。鉴定和表征真菌病原体中其他Rab调节因子应有助于理解不同丝状真菌中的自噬和内吞作用。在此，我们在该真菌中鉴定并表征了酵母同源物。靶向基因缺失表明其对该真菌的生长、分生孢子形成和毒力很重要。细胞学检查显示FolVps9与FolVps21（早期内体标记物）共定位，并在内吞作用和自噬体降解中起关键作用。下拉实验表明FolVps9与FolVps21相互作用，这对该真菌的发育和植物感染也很重要。酵母双杂交、双分子荧光互补和免疫共沉淀实验表明FolVps9特异性地与FolVps21的GDP结合形式相互作用。此外，FolVps21的组成型活性形式（Q72L）能够挽救Δ和Δ突变体的缺陷。总之，我们的研究提供了确凿证据，表明FolVps9作为FolVps21鸟嘌呤核苷酸交换因子（GEFs）来调节内吞作用和自噬，从而控制该真菌的营养生长、无性发育和致病性
