Dissecting complex genetic interaction networks mediating the fungal stress response

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Microbial organisms encounter a range of environmental stress conditions, including changes in nutrient availability, pH, temperature, and other stressors and their survival is contingent on their abilities to sense, respond, and adapt to these changes. One such micro-organism is Candida albicans: a fungus commonly found in the healthy human microbiome, and an opportunistic pathogen. C. albicans encounters and tolerates a range of stress conditions, including temperature fluctuations within hosts, and assaults from the immune system. In response to stress, C. albicans can undergo a cellular morphogenesis program, and transition from a round, yeast morphology, to an elongated filamentous form. To understand how C. albicans tolerates and responds to stress, we must identify the genetic factors and genetic interactions that govern their stress response. My research program will use cutting-edge genetic technologies to address fundamental questions in fungal biology: which genetic factors and genetic interactions regulate the C. albicans stress response? How are genetic interactions conserved across different stress conditions? Are the same genetic networks involved in stress response and morphogenesis? My previous work established the Gene Drive Array (GDA)' a CRISPR-based platform to create single and double genetic mutants in C. albicans and facilitate our ability to perform complex genetic interaction analysis. Building on this, my proposed research program will modify the GDA system to allow us to build C. albicans genetic mutant libraries on a larger scale. We will use this technology to build a library of C. albicans strains containing mutations in key stress response factors both singly, and in every combination of double mutations. The library will be screened under diverse stress conditions, to identify genetic factors and genetic interactions that govern survival and response to stress. Microscopic and imaging analysis will be used to determine how stress conditions and mutations influence morphogenesis in C. albicans. We will use computational analysis to build genetic interaction networks, and use molecular genetic and biochemical techniques to dissect cellular pathways, and determine the mechanisms by which these factors govern the stress response. This work has important implications for our understanding of the fungal stress response, and the technologies we develop will be generalizable across a diversity of microbial organisms.