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Functional analysis of the conserved transcriptional regulator CfWor1 in C ladosporium fulvum reveals diverse roles in the virulence of plant pathogenic fungi
Author(s) -
Ökmen Bilal,
Collemare Jérôme,
Griffiths Scott,
Burgt Ate,
Cox Russell,
Wit Pierre J. G. M.
Publication year - 2014
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.12535
Subject(s) - virulence , biology , mutant , effector , complementation , gene , genetics , fungal protein , microbiology and biotechnology
Summary Fungal W or1‐like proteins are conserved transcriptional regulators that are reported to regulate the virulence of several plant pathogenic fungi by affecting the expression of virulence genes. Here, we report the functional analysis of CfWor1 , the homologue of W or1 in C ladosporium fulvum . Δ cfwor1 mutants produce sclerotium‐like structures and rough hyphae, which are covered with a black extracellular matrix. These mutants do not sporulate and are no longer virulent on tomato. A CE . CfWor1 transformant that constitutively expresses CfWor1 produces fewer spores with altered morphology and is also reduced in virulence. RNA ‐seq and RT‐qrtPCR analyses suggest that reduced virulence of Δ cfwor1 mutants is due to global downregulation of transcription, translation and mitochondrial respiratory chain. The reduced virulence of the CE . CfWor1 transformant is likely due to downregulation of effector genes. Complementation of a non‐virulent Δ fosge1 ( W or1‐homologue) mutant of F usarium oxysporum f. sp. lycopersici with CfWor1 restored expression of the SIX effector genes in this fungus, but not its virulence. Chimeric proteins of CfWor1 / FoSge 1 also only partially restored defects of the Δ fosge1 mutant, suggesting that these transcriptional regulators have functionally diverged. Altogether, our results suggest that CfWor1 primarily regulates development of C . fulvum , which indirectly affects the expression of a subset of virulence genes.