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The Botrytis cinerea PAK kinase BcCla4 mediates morphogenesis, growth and cell cycle regulating processes downstream of BcRac
Author(s) -
MinzDub Anna,
Sharon Amir
Publication year - 2017
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13642
Subject(s) - biology , effector , microbiology and biotechnology , morphogenesis , botrytis cinerea , kinase , gtpase , genetics , botany , gene
Summary Rac proteins are involved in a variety of cellular processes. Effector proteins that interact with active Rac convey the GTPase‐generated signal to downstream developmental cascades and processes. Here we report on the analysis of the main effector and signal cascade downstream of BcRac, the Rac homolog of the grey mold fungus Botrytis cinerea . Several lines of evidence highlighted the p21‐activated kinase Cla4 as an important effector of Rac in fungi. Analysis of Δ bccla4 strains revealed that the BcCla4 protein was sufficient to mediate all of the examined BcRac‐driven processes, including hyphal growth and morphogenesis, conidia production and pathogenicity. In addition, the Δ bccla4 strains had altered nuclei content, a phenomenon that was previously observed in Δ bcrac isolates, thus connecting the BcRac/BcCla4 module with cell cycle control. Further analyses revealed that BcRac/BcCla4 control mitotic entry through changes in phosphorylation status of the cyclin dependent kinase BcCdk1. The complete cascade includes the kinase BcWee1, which is downstream of BcCla4 and upstream of BcCdk1. These results provide a mechanistic insight on the connection of cell cycle, morphogenesis and pathogenicity in fungi, and position BcCla4 as the most essential effector and central regulator of all of these processes downstream of BcRac.