Cytokinesis-required Cdc14 is a signaling hub of asexual development and multi-stress tolerance in Beauveria bassiana

Abstract

A dual-specificity, paralogue-free Cdc14 phosphatase was located in the nuclei of Beauveria bassiana (filamentous entomopathogen) and functionally characterized. Inactivation of cdc14 caused defective cytokinesis due to multinucleate cells formed in Δcdc14 and 89% decrease of blastospore production, followed by slower growth and a loss of ≥ 96% conidial yield under normal conditions. These defects coincided well with drastic down-regulation of 25 genes required for mitosis and conidiation. Moreover, Δcdc14 became hypersensitive to oxidative, osmotic, and cell wall and mitosis perturbing stresses, and lost 41−70% of conidial thermotolerance, UV-B resistance and virulence, accompanied with transcriptional down-regualtion of various signaling factors and stress-responsive effectors and depressed phosphorylation signals of Hog1 and Slt2 in high-osmolarity glycerol and cell-wall integrity pathways. All changes were well restored by rescuing cdc14. Our findings indicate that Cdc14 vital for the fungal cytokinesis acts as a signaling hub in regulating not only asexual development but multi-stress responses and virulence.

FgCDC14 regulates cytokinesis, morphogenesis, and pathogenesis in Fusarium graminearum

“…Given that proper regulation of cell cycle progression is important for fungal development and pathogenesis in fungal pathogens (Pérez‐Martín et al ., ), the observed phenotypes are consistent with known cell cycle regulatory functions for Cdc14 in budding and fission yeasts. In B. bassiana , BbCdc14 is also important for asexual reproduction and insect infection (Wang et al ., ). In C. albicans , CaCdc14p activity is required for true hyphal growth and invasion (Clemente‐Blanco et al ., ).…”

“…In the entomopathogenic fungus Beauveria bassiana , BbCdc14 is not essential, but is important for asexual development, stress responses and virulence. Inactivation of BbCDC14 results in the formation of multinucleate cells and defects in conidiation and pathogenesis (Wang et al ., ). In the human pathogen C. albicans , CaCDC14 is not essential for vegetative growth, but affects late cell cycle events and morphogenesis.…”

MoCDC14 is important for septation during conidiation and appressorium formation in Magnaporthe oryzae

“…In M. oryzae, MoCDC14 encodes a typical Cdc14 phosphatase protein, with the HCX5R catalytic site sequence (Mocciaro and Schiebel, 2010). The Mocdc14 mutant is viable, but shows a significantly reduced growth rate, which is similar to the cdc14 mutants in F. graminearum and B. bassiana Wang et al, 2013). However, deletion of the CDC14 orthologue produces no obvious defects in growth rate in A. nidulans (Son and Osmani, 2009) or C. albicans (Clemente-Blanco et al, 2006).…”

“…The Mocdc14 mutant shows reduced conidiation and the majority of mutant conidia contain only one or two nuclei without a septum or with only one incomplete septum. In the entomopathogenic fungus B. bassiana, the Cdc14 orthologue also acts as a positive regulator of asexual development (Wang et al, 2013(Wang et al, , 2016. In addition to reduced conidiation, the Mocdc14 mutant is also defective in conidium morphology.…”

“…Clp1 reverses Cdk1-mediated phosphorylation of the mitotic inducer Cdc25 and promotes its degradation by the anaphasepromoting complex at the end of mitosis (Esteban et al, 2004;Wolfe and Gould, 2004). In the filamentous fungi Aspergillus nidulans, F. graminearum and Beauveria bassiana, the CDC14 orthologues are also dispensable for viability, but important for asexual development Son and Osmani, 2009;Wang et al, 2013). In the human pathogen Candida albicans, deletion of CaCDC14 has no effect on growth rate, but results in defects in cell separation, mitotic exit and morphogenesis (Clemente-Blanco et al, 2006).…”