The DUF1996 and WSC domain‐containing protein Wsc1I acts as a novel sensor of multiple stress cues in Beauveria bassiana

• Published in: Cellular microbiology Vol. 21; no. 12; pp. e13100 - n/a
• Main Authors: Tong, Sen‐Miao, Wang, Ding‐Yi, Gao, Ben‐Jie, Ying, Sheng‐Hua, Feng, Ming‐Guang
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.12.2019
• Subjects: Beauveria bassiana; Cations; cell injury/sublethal injury; Cell membranes; Cell walls; Clonal deletion; Complementation; Conidia; Copper; Deletion mutant; filamentous fungi; Fungi; genotyping; Hog1 protein; Homology; Insects; Iron; Irradiation; Kinases; Magnesium; Metal ions; molecular genetic; Organic chemistry; Oxidants; Oxidizing agents; Phosphorylation; Protein kinase; Proteins; Signal transduction; stress response; Ultraviolet radiation; Vacuoles; Virulence; Zinc; cell injury/sublethal injury; filamentous fungi; stress response; molecular genetic; genotyping
• DOI: 10.1111/cmi.13100
• ISSN: 1462-5814; 1462-5822

Wsc1I homologues featuring both an N‐terminal DUF1996 (domain of unknown function 1996) and a C‐terminal WSC (cell wall stress‐responsive component) domain exist in filamentous fungi but have never been functionally characterized. Here, Wsc1I is shown to localize in the vacuoles and cell wall/membrane of the insect mycopathogen Beauveria bassiana and hence linked to cell membrane‐ and vacuole‐related cellular events. In B. bassiana, deletion of Wsc1I resulted in marked increases of hyphal and conidial sensitivities to hyperosmotic agents, oxidants, cell wall perturbing chemicals, and metal cations (Cu2+, Zn2+, Fe2+, and Mg2+) despite slight impact on normal growth and conidiation. Conidia produced by the deletion mutant showed not only reduced tolerance to both 45°C heat and UVB irradiation but also attenuated virulence to a susceptible insect through normal cuticle infection or cuticle‐bypassing infection. Importantly, phosphorylation of the mitogen‐activated protein kinase Hog1 was largely attenuated or nearly abolished in the Wsc1I‐free cells triggered with hyperosmotic, oxidative, or cell wall perturbing stress. All changes were well restored by targeted gene complementation. Our findings highlight a novel role of Wsc1I in sensing multiple stress cues upstream of the Hog1 signalling pathway and its pleiotropic effects in B. bassiana.