Nguyen Hang T T, Choi Soyoung, Kim Soonok, Lee Ju-Hee, Park Ae Ran, Yu Nan Hee, Yoon Hyeokjun, Bae Chang-Hwan, Yeo Joo Hong, Choi Gyung Ja, Son Hokyoung, Kim Jin-Cheol
Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Science, Chonnam National University, Gwangju, South Korea.
Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.
Front Plant Sci. 2020 Apr 2;11:371. doi: 10.3389/fpls.2020.00371. eCollection 2020.
Endophytic fungi are great resources for the identification of useful natural products such as antimicrobial agents. In this study, we performed the antifungal screening of various plant endophytic fungi against the dollar spot pathogen and finally selected sp. JS-0112 as a potential biocontrol agent. The bioactive compound produced by the strain JS-0112 was identified as monorden known as an inhibitor of heat shock protein 90 (Hsp90). Monorden exhibited strong antagonistic activity against most tested plant pathogenic fungi particularly against tree pathogens and oomycetes with the minimum inhibitory concentration values less than 2.5 μg mL. Extensive assays revealed that monorden effectively suppressed the development of several important plant diseases such as rice blast, rice sheath blight, wheat leaf rust, creeping bentgrass dollar spot, and cucumber damping-off. Especially, it showed much stronger disease control efficacy against cucumber damping-off than a synthetic fungicide chlorothalonil. Subsequent molecular genetic analysis of fission yeast and suggested that Hsp90 is a major inhibitory target of monorden, and sequence variation among fungal Hsp90 is a determinant for the dissimilar monorden sensitivity of fungi. This is the first report dealing with the disease control efficacy and antifungal mechanism of monorden against fungal plant diseases and we believe that monorden can be used as a lead molecule for developing novel fungicides with new action mechanism for the control of plant diseases caused by fungi and oomycetes.
内生真菌是鉴定抗菌剂等有用天然产物的重要资源。在本研究中，我们对多种植物内生真菌进行了针对美元斑病菌的抗真菌筛选，最终选择了JS-0112菌株作为潜在的生物防治剂。菌株JS-0112产生的生物活性化合物被鉴定为莫能菌素，它是一种热休克蛋白90（Hsp90）抑制剂。莫能菌素对大多数测试的植物病原真菌表现出强烈的拮抗活性，尤其是对树木病原菌和卵菌，其最低抑菌浓度值小于2.5μg/mL。广泛的试验表明，莫能菌素能有效抑制几种重要植物病害的发展，如稻瘟病、水稻纹枯病、小麦叶锈病、匍匐翦股颖美元斑病和黄瓜猝倒病。特别是，它对黄瓜猝倒病的防治效果比合成杀菌剂百菌清要强得多。随后对裂殖酵母的分子遗传学分析表明，Hsp90是莫能菌素的主要抑制靶点，真菌Hsp90之间的序列变异是真菌对莫能菌素敏感性不同的决定因素。这是关于莫能菌素对植物真菌病害的防治效果和抗真菌机制的首次报道，我们相信莫能菌素可作为一个先导分子，用于开发具有新作用机制的新型杀菌剂，以防治由真菌和卵菌引起的植物病害。
