AUTHOR=Xia Huiqing , Chen Linlin , Fan Zhuo , Peng Mengya , Zhao Jingya , Chen Wenbo , Li Haiyang , Shi Yan , Ding Shengli , Li Honglian 

TITLE=Heat Stress Tolerance Gene FpHsp104 Affects Conidiation and Pathogenicity of Fusarium pseudograminearum

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.695535

DOI=10.3389/fmicb.2021.695535

ISSN=1664-302X

ABSTRACT=<p>Heat shock protein Hsp104, a homolog of the bacterial chaperone ClpB and plant Hsp100, plays an essential part in the response to heat and various chemical agents in <italic>Saccharomyces cerevisiae</italic>. However, their functions remain largely unknown in plant fungal pathogens. Here, we report the identification and functional characterization of a plausible ortholog of yeast Hsp104 in <italic>Fusarium pseudograminearum</italic>, which we termed FpHsp104. Deletion mutant of FpHsp104 displayed severe defects in the resistance of heat shock during <italic>F. pseudograminearum</italic> mycelia and conidia when exposed to extreme heat. We also found that the protein showed dynamic localization to small particles under high temperature. However, no significant differences were detected in osmotic, oxidative, or cell wall stress responses between the wild-type and Δ<italic>fphsp104</italic> strains. Quantitative real-time PCR analysis showed that <italic>FpHsp104</italic> was upregulated in the conidia, and disruption of <italic>FpHsp104</italic> gene resulted in defects in conidia production, morphology, and germination. The transcript levels of conidiation-related genes of <italic>FpFluG</italic>, <italic>FpVosA</italic>, <italic>FpWetA</italic>, and <italic>FpAbaA</italic> were reduced in the Δ<italic>fphsp104</italic> mutant vs. the wild-type strain, but heat-shocked mRNA splicing repair was not affected in Δ<italic>fphsp104</italic>. Moreover, Δ<italic>fphsp104</italic> mutant also showed attenuated virulence, but its DON synthesis was normal. These data from the first study of Hsp104 in <italic>F. pseudograminearum</italic> strongly suggest that <italic>FpHsp104</italic> gene is an important element in the heat tolerance, development, and pathogenicity processes of <italic>F. pseudograminearum</italic>.</p>