Poster
Julian A. Liber
PhD Candidate
Duke University
Durham, North Carolina, United States
Audrey Williams
Postdoctoral Researcher
Duke University
Durham, North Carolina, United States
Claudia Petrucco
PhD Candidate
Duke University
Durham, North Carolina, United States
Alex Crocker
PhD Candidate
University of North Carolina Chapel Hill
Chapel Hill, North Carolina, United States
Amy Gladfelter
Professor
Duke University
Durham, North Carolina, United States
Sheng Yang He, PhD
Professor
Duke University, HHMI
Durham, NC, USA
Aureobasidium pullulans is a near-ubiquitous leaf-inhabiting fungus used agronomically for biocontrol of fire blight and post-harvest rots and in industrial fermentation. While notable as a polyextremotolerant species of radiation, pH, and osmotic stresses, it also grows to abundance on plant surfaces. However, the role of its traits in plant colonization and the genetic basis of its polyextremotolerance are not yet known. We can leverage the species’ significant phenotypic and genetic variation to detect traits involved in plant colonization and biocontrol as well as the underlying genetic loci via multiple methods. We isolated or obtained sequenced isolates to create a panel of 210 genome-sequenced European and N. American isolates. This panel included 3.9 million high-quality SNPs and revealed novel population structure previously unobserved in the species. Isolates were characterized for a variety of stress tolerance, metabolic, and morphological traits. Plant colonization experiments suggest that nutrient utilization, pH buffering, and tolerance of H2O2 predict colonization success. Genome-wide association implicated many loci in these traits, which are undergoing validation via gene deletion, complementation, and overexpression. This approach offers to identify mechanisms of adaptation to the phyllosphere which may be common across other resident taxa, as well as to develop A. pullulans strains with enhanced trait profiles for agriculture and other industries.