|Wang, Xuefei - Washington State University|
|Glawe, Dean - Washington State University|
Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/13/2018
Publication Date: 1/17/2018
Citation: Okubara, P.A., Wang, X., Weller, D.M., Glawe, D. 2018. Botrytis and native grape yeasts – not all interactions are created equal. Plant and Animal Genome Conference. W775.
Technical Abstract: Native yeasts are of increasing interest to grape growers and winemakers in Washington State because of their potential to contribute to vineyard health and wine quality. In this pilot project, we used eleven strains of native yeasts and nine isolates of the Botrytis bunch rot pathogen, all obtained from Washington grapes. The yeasts included Candida saitoana, Curvibasidium pallidicorallinum, Metschnikowia chrysoperlae, Metschnikowia pulcherrima, Meyerozyma guilliermondii, Wickerhamomyces anomalus and Aureobasidium pullulans. Our objectives were to assess the biocontrol activities of each yeast, and to determine how the pathogen isolates responded to them. In laboratory assays, the native yeasts rapidly and extensively colonized artificial wounds on Thompson Seedless berries, showing about a 10,000-fold increase in population density per wound site within two days of introduction. Eight of the nine Botrytis isolates produced substantial symptoms on grape berries, generating disease severity ratings of 5.1-5.7 on a scale of 0 (healthy) to 7 (shrunken berry covered by fungus). However, each of the yeasts varied in their ability to suppress symptoms induced by four selected pathogen isolates when tested on grape berries. Our findings show that interactions on the berry depend on both yeast strain and Botrytis isolate. Biocontrol activity on the berry was not always reflected in inhibition assays on synthetic medium, suggesting that niche or nutrient competition was a likely biocontrol mechanism in planta. Finally, nutrient utilization differed among yeast species, indicating that co-deployment of more than one yeast might be a potential strategy for control of Botrytis bunch rot in the vineyard.