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Environmental and genetic regulation of white‐opaque switching in Candida tropicalis
Author(s) -
Zheng Qiushi,
Zhang Qiuyu,
Bing Jian,
Ding Xuefen,
Huang Guanghua
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.13862
Subject(s) - candida tropicalis , biology , phenotypic switching , candida albicans , corpus albicans , phenotype , transcription factor , genetics , white (mutation) , gene , microbiology and biotechnology
Summary Phenotypic switching is a strategy by which microbial organisms adapt to environmental changes. The human fungal pathogens, Candida albicans and Candida tropicalis , are closely related species and capable of undergoing morphological transitions. C. albicans primarily exists in human or warm‐blooded animals as a commensal, whereas C. tropicalis not only exists as a commensal but also is widely distributed in the environment. In this study, we describe the environmental and genetic regulatory mechanisms of white‐opaque switching in C. tropicalis , which is associated with virulence and sexual mating. A comparative study with C. albicans demonstrated that C. tropicalis responds to environmental stimuli, such as elevated CO 2 levels and pH changes, in opposite manners. An acidic pH and elevated CO 2 levels promote the opaque phenotype in C. albicans but have an opposite effect in C. tropicalis , whereas alkaline pH conditions facilitate white‐to‐opaque switching and sexual mating in C. tropicalis . The conserved Rim101‐mediated pH sensing and Ras1‐cAMP/PKA signaling pathways are involved in this regulation. By screening an overexpression library of transcription factors, we identified 26 white‐opaque regulators, including WOR1 , AHR1 , EFG1 , CUP9 , BCR1 and SFL2 . Transcriptional analysis indicated that the pH sensing and Ras1‐cAMP/PKA signaling pathways and transcriptional regulators coordinately regulate white‐to‐opaque switching.