Genetics of thermotolerance in Cryptococcus neoformans

Fungal pathogens are remarkably adept at adapting to constantly changing environments including changing temperatures and increased thermotolerance is often thought of as a primary virulence factor of these microbes. To understand how fungi are able to evolve thermotolerance, we serially passaged the Cryptococcus neoformans strain Ftc239-1 at gradually increasing temperatures. Fungal cells were passaged for 40 days at temperatures ranging from 30-35C and were subsequently assessed for a change in their ability to withstand thermal stress and grow at high temperatures. Populations and individual clonal isolates were identified with increased thermotolerance and genetic changes in these populations were identified by whole genome sequencing. High quality genomic DNA was extracted from lyophilized cell pellets using CTAB extraction protocols.