Investigation of CO2 tolerance in the global pathogen Cryptococcus neoformans
Cryptococcus neoformans is a ubiquitous free-living soil yeast and opportunistic pathogen that causes ~223,100 cases of cryptococcal meningitis per year, killing over 180,000 people. The most commonly studied virulence factor that helps this fungus to adapt to the host condition is thermotolerance. However, a major understudied factor that differs between the natural environmental niche of C. neoformans and its human host is CO2. While the ambient atmosphere only contains about 0.04% CO2, the human body CO2 level can range from 5-10%. It was recently found that while clinical isolates are tolerant to host levels of CO2, many environmental isolates are CO2-sensitive and virulence-attenuated in animal models. The purpose of the study is to identify genetic loci contributing to CO2 tolerance and virulence in Cryptococcus neoformans.