PDF(Pubmed)
Abstract：
The RNA exosome complex is a conserved, multisubunit RNase complex that contributes to the processing and degradation of RNAs in mammalian cells. However, the roles of the RNA exosome in phytopathogenic fungi and how it relates to fungal development and pathogenicity remain unclear. Herein, we identified 12 components of the RNA exosome in the wheat fungal pathogen Fusarium graminearum. Live-cell imaging showed that all the components of the RNA exosome complex are localized in the nucleus. FgEXOSC1 and FgEXOSCA were successfully knocked out; they are both involved in the vegetative growth, sexual reproduction, and pathogenicity of F. graminearum. Moreover, deletion of FgEXOSC1 resulted in abnormal toxisomes, decreased deoxynivalenol (DON) production, and downregulation of the expression levels of DON biosynthesis genes. The RNA-binding domain and N-terminal region of FgExosc1 are required for its normal localization and functions. Transcriptome sequencing (RNA-seq) showed that the disruption of FgEXOSC1 resulted in differential expression of 3,439 genes. Genes involved in processing of noncoding RNA (ncRNA), rRNA and ncRNA metabolism, ribosome biogenesis, and ribonucleoprotein complex biogenesis were significantly upregulated. Furthermore, subcellular localization, green fluorescent protein (GFP) pulldown, and coimmunoprecipitation (co-IP) assays demonstrated that FgExosc1 associates with the other components of the RNA exosome to form the RNA exosome complex in F. graminearum. Deletion of FgEXOSC1 and FgEXOSCA reduced the relative expression of some of the other subunits of the RNA exosome. Deletion of FgEXOSC1 affected the localization of FgExosc4, FgExosc6, and FgExosc7. In summary, our study reveals that the RNA exosome is involved in vegetative growth, sexual reproduction, DON production, and pathogenicity of F. graminearum. IMPORTANCE The RNA exosome complex is the most versatile RNA degradation machinery in eukaryotes. However, little is known about how this complex regulates the development and pathogenicity of plant-pathogenic fungi. In this study, we systematically identified 12 components of the RNA exosome complex in Fusarium head blight fungus Fusarium graminearum and first unveiled their subcellular localizations and established their biological functions in relation to the fungal development and pathogenesis. All the RNA exosome components are localized in the nucleus. FgExosc1 and FgExoscA are both required for the vegetative growth, sexual reproduction, DON production and pathogenicity in F. graminearum. FgExosc1 is involved in ncRNA processing, rRNA and ncRNA metabolism process, ribosome biogenesis and ribonucleoprotein complex biogenesis. FgExosc1 associates with the other components of RNA exosome complex and form the exosome complex in F. graminearum. Our study provides new insights into the role of the RNA exosome in regulating RNA metabolism, which is associated with fungal development and pathogenicity.
摘要：
RNA外泌体复合物是保守的，促进哺乳动物细胞中RNA加工和降解的多亚基RNA酶复合物。然而,RNA外泌体在植物病原性真菌中的作用及其与真菌发育和致病性的关系尚不清楚.在这里，我们在小麦真菌病原体镰刀菌中鉴定了RNA外泌体的12种成分。活细胞成像显示，RNA外泌体复合物的所有成分都位于细胞核中。FgEXOSC1和FgEXOSCA被成功敲除；它们都参与了营养生长，有性生殖,和致病性。此外，FgEXOSC1缺失导致异常毒物，脱氧雪腐镰刀菌烯醇（DON）产量减少，和下调DON生物合成基因的表达水平。FgExosc1的RNA结合域和N末端区域是其正常定位和功能所必需的。转录组测序（RNA-seq）显示，FgEXOSC1的破坏导致3,439个基因的差异表达。参与非编码RNA（ncRNA）加工的基因，rRNA和ncRNA代谢，核糖体生物发生，核糖核蛋白复合物的生物合成显著上调。此外，亚细胞定位，绿色荧光蛋白（GFP）下拉，和共免疫沉淀（co-IP）测定表明，FgExosc1与RNA外泌体的其他成分结合在一起，以形成F.graminearum中的RNA外泌体复合物。FgEXOSC1和FgEXOSCA的缺失降低了RNA外泌体的一些其他亚基的相对表达。FgEXOSC1的缺失影响FgExosc4、FgExosc6和FgExosc7的定位。总之,我们的研究表明，RNA外泌体参与营养生长，有性生殖,DON生产,和致病性。重要性RNA外泌体复合物是真核生物中最通用的RNA降解机制。然而,关于这种复合物如何调节植物病原真菌的发育和致病性知之甚少。在这项研究中,我们系统地鉴定了枯萎病镰刀菌中RNA外泌体复合物的12个成分，并首次揭示了它们的亚细胞定位，并建立了它们与真菌发育和发病机理有关的生物学功能。所有RNA外泌体组分都位于细胞核中。FgExosc1和FgExoscA都是营养生长所必需的，有性生殖,谷草的DON产生和致病性。FgExosc1参与ncRNA加工，rRNA和ncRNA代谢过程，核糖体生物发生和核糖核蛋白复合物生物发生。FgExosc1与RNA外泌体复合物的其他成分结合，并在禾谷草中形成外泌体复合物。我们的研究为RNA外泌体在调节RNA代谢中的作用提供了新的见解，这与真菌的发育和致病性有关。
