Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon 305-806, South Korea.
Microbial Resource Center, KRIBB, Jeongeup 56212, South Korea.
Sci Rep. 2017 Jan 10;7:39432. doi: 10.1038/srep39432.
Yeast associates with many plant parts including the phyllosphere, where it is subject to harsh environmental conditions. Few studies have reported on biological control of foliar pathogens by yeast. Here, we newly isolated leaf-colonizing yeasts from leaves of field-grown pepper plants in a major pepper production area of South Korea. The yeast was isolated using semi-selective medium supplemented with rifampicin to inhibit bacterial growth and its disease control capacity against Xanthomonas axonopodis infection of pepper plants in the greenhouse was evaluated. Of 838 isolated yeasts, foliar spray of Pseudozyma churashimaensis strain RGJ1 at 10 cfu/mL conferred significant protection against X. axonopodis and unexpectedly against Cucumber mosaic virus, Pepper mottle virus, Pepper mild mottle virus, and Broad bean wilt virus under field conditions. 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 and has potential for effective disease management in the field.
酵母与许多植物部位有关，包括叶际，在那里它会受到恶劣环境条件的影响。很少有研究报道酵母对叶部病原菌的生物防治。在这里，我们从韩国主要辣椒生产区田间种植的辣椒叶片中分离到了新的定殖于叶片的酵母。该酵母是使用半选择性培养基分离出来的，培养基中添加了利福平以抑制细菌生长，并在温室中评估了其对辣椒植株上丁香假单胞菌感染的防治能力。在分离出的 838 株酵母中，将假丝酵母 RGJ1 菌株以 10cfu/mL 的浓度喷雾到叶片上，可显著防治丁香假单胞菌，出乎意料的是，还能防治黄瓜花叶病毒、辣椒斑驳病毒、辣椒轻斑驳病毒和蚕豆萎蔫病毒。从共培养试验中未检测到 RGJ1 菌株与丁香假单胞菌之间的直接拮抗作用，这表明病害是通过诱导抗性来抑制的。对诱导抗性标记基因辣椒病程相关蛋白（CaPR）4 和 CaPR5 的进一步分子分析表明，RGJ1 菌株诱导了植物防御的启动。据我们所知，这项研究首次报道了一种定殖于叶片的酵母对细菌和病毒病原体的植物保护作用，具有在田间进行有效病害管理的潜力。
