AUTHOR=Ren Weichao , Liu Na , Yang Yalan , Yang Qianqian , Chen Changjun , Gao Qingli 

TITLE=The Sensor Proteins BcSho1 and BcSln1 Are Involved in, Though Not Essential to, Vegetative Differentiation, Pathogenicity and Osmotic Stress Tolerance in Botrytis cinerea

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.00328

DOI=10.3389/fmicb.2019.00328

ISSN=1664-302X

ABSTRACT=<p>High-osmolarity glycerol (HOG) signaling pathway belongs to mitogen-activated protein kinase (MAPK) cascades that regulate responses of organism to diverse extracellular stimuli. The membrane spanning proteins Sho1 and Sln1 serve as biosensors of HOG pathway in <italic>Saccharomyces cerevisiae</italic>. In this study, we investigated the biological functions of <italic>BcSHO1</italic> and <italic>BcSLN1</italic> in the gray mold fungus <italic>Botrytis cinerea</italic>. Target gene deletion demonstrated that both <italic>BcSHO1</italic> and <italic>BcSLN1</italic> are important for mycelial growth, conidiation and sclerotial formation. The <italic>BcSHO1</italic> and <italic>BcSLN1</italic> double deletion mutant Δ<italic>BcSln1-Sho1</italic> produced much more, but smaller sclerotia than Δ<italic>BcSho1</italic> and the wild-type (WT) strain, while Δ<italic>BcSln1</italic> failed to develop sclerotia on all tested media, instead, formed a large number of conidia. Infection tests revealed that the virulence of Δ<italic>BcSln1-Sho1</italic> decreased significantly, however, Δ<italic>BcSho1</italic> or Δ<italic>BcSln1</italic> showed no difference with the WT strain. In addition, Δ<italic>BcSln1-Sho1</italic> exhibited resistance to osmotic stress by negatively regulating the phosphorylation of BcSak1 (yeast Hog1). All the phenotypic defects of mutants were recovered by target gene complementation. These results suggest that <italic>BcSHO1</italic> and <italic>BcSLN1</italic> share some functional redundancy in the regulation of fungal development, pathogenesis and osmotic stress response in <italic>B. cinerea</italic>.</p>