AUTHOR=Chen Qi , Li Yongbing , Wang Jinzi , Li Ru , Chen Baoshan 

TITLE=cpubi4 Is Essential for Development and Virulence in Chestnut Blight Fungus

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.01286

DOI=10.3389/fmicb.2018.01286

ISSN=1664-302X

ABSTRACT=<p>Ubiquitination plays key roles in eukaryotic growth, stress adaptation, and metabolic regulation. In our previous work, ubiquitin was found to be secreted in the hypovirus-infected strain of <italic>Cryphonectria parasitica</italic>, a phytopathogenic filamentous fungus responsible for the chestnut blight. Here we report the functional and molecular characterization of a polyubiquitin gene, <italic>cpubi4</italic>, in <italic>C. parasitica</italic>. The expression of <italic>cpubi4</italic> was upregulated by the infection of a hypovirus. Deletion of <italic>cpubi4</italic> resulted in abnormal morphology, reduced sporulation, attenuation of virulence, and significant reduction in ubiquitination. A total of 378 sites in 236 proteins were identified to be significantly decreased in ubiquitination in the absence of <italic>cpubi4</italic>. Quantitative proteome analysis revealed that 285 in 4,776 identified proteins changed in abundance (1.5-fold, <italic>P</italic> &lt; 0.05) in the <italic>cpubi4</italic> null mutant, as compared with the wild-type strain.</p>