Find new, safe natural compounds to improve activity of fungicides for treatment of apple and use genomic tools to determine target genes to improve suppression of apple decay. Determine method for delivery of newly discovered compounds; and identify molecular targets; augment antifungal activity of natural compounds, through synthesis of structural derivatives, based on structure-activity relationships of analogs.
Approach: Saccharomyces cerevisiae will be used in high-throughput bioassays to identify molecular targets. Strains of S. cerevisiae lacking particular functional genes for 1) signal transduction, 2) gene regulation, 3) antioxidation, 4) transporter or assembly proteins, and 5) DNA damage control/enzymes for energy metabolism will be used to screen biological activity of compounds. Penicillium expansum, two apple pathogens isolated from infected apples and other filamentous fungi (e.g., Aspergillus) are currently available in our laboratory. Information from NCBI will be used for a comparative genomics approachto identify target genes of natural compounds in apple pathogens, and also for early detection of pathogenic Penicillium sp. on apple. Complementation analysis of yeast mutants lacking target genes will be used to verify orthology of targets in filamentous fungi. Synergistic growth inhibition of fungi by co-application of test compounds will be added to the medium with fludioxonil, strobilurin, carboxin or other conventional fungicides.