Fungi living within and on leaf surfaces play an integral role in host functional processes including plant growth, stress tolerance, and pathogen resistance. The microbial compositions and subsequent interactions occurring at these interfaces play a large role in mediating these plant host processes. Foliar yeasts are a particular group of unicellular fungi that have been extensively studied for their antagonistic nature towards foliar, flower, and fruit microbes. Less studied, however, is the way yeasts associate with other commensal microbes and persist in the phyllosphere. This knowledge is integral to assessing how various microbe compositions affect plant processes over diverse biotic and abiotic conditions. In this study we characterize various competitive traits of foliar yeasts isolated from tomato, Solanum lycopersicum, leaves, including dispersal (ballistospore formation), In vitro antagonism (dual cultural assays), and in planta assembly over time (density-dependent inoculations).
Results/Conclusions
In vitro antagonism was quantified using dual cultural assays and no direct inhibitory compound excretion was identified between the seven environmental yeast strain isolates. Temporal sampling of density-dependent inoculations of three dominant epiphytic yeasts on S. lycopersicum showed competitive interactions between two dominant yeasts. These quantified competitive interactions bring us a step closer to modeling species interactions in the phyllosphere microbiome and predicting community composition in different abiotic and biotic conditions.