Foliar application of the leaf-colonizing yeast Pseudozyma churashimaensis elicits systemic defense of pepper against bacterial and viral pathogens
C. RYU (1), G. Lee (2), S. Lee (2), K. Kim (2) (1) KRIBB, Youseong, South Korea; (2) KRIBB, South Korea

Yeast associates with many plant space including phyllosphere where is subject to harsh environmental conditions such as UV and limited moisture and nutrients. Few studies have reported on biological control methods against foliar pathogens. Here, we newly isolated leaf-colonizing yeasts from leaves of pepper plants that were grown in the field in a major pepper production area of South Korea. The yeast was isolated using semi-selective medium supplemented with rifampicin to inhibit bacterial growth. We evaluated the yeast isolates for their disease control capacity against Xanthomonas axonopodis infection of pepper plants in the greenhouse. Of 838 isolated yeasts, foliar spray of Pseudozyma churashimaensis strain RGJ1 at 107 cfu/mL conferred significant protection against X. axonopodis, Cucumber mosaic virus, Pepper mottle virus, Pepper mild mottle virus and Broad bean wilt virus under field condition. Direct antagonism between strain RGJ1 and X. axonopodis was not detected from co-culture assays, suggesting that disease is suppressed via induced resistance. Additional molecular analysis of the induced resistance marker genes Capsicum annuum Pathogenesis-Related (CaPR) 4 and CaPR5 indicated that strain RGJ1 elicited plant defense priming. To our knowledge, this study is the first report of plant protection against bacterial and viral pathogens mediated by a leaf-colonizing yeast.

Abstract Number: P5-128
Session Type: Poster