Tao Xiaoyuan, Zhang Hailin, Gao Mengtao, Li Menglin, Zhao Ting, Guan Xueying
College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Hybrid R & D Engineering Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing, 210095, China.
AMB Express. 2020 Oct 28;10(1):193. doi: 10.1186/s13568-020-01132-1.
Verticillium wilt (VW) caused by Verticillium dahliae is a devastating soil-borne disease that causes severe yield losses in cotton and other major crops worldwide. Here we conducted a high-throughput screening of isolates recovered from 886 plant rhizosphere samples taken from the three main cotton-producing areas of China. Fifteen isolates distributed in different genera of bacteria that showed inhibitory activity against V. dahliae were screened out. Of these, two Pseudomonas strains, P. protegens XY2F4 and P. donghuensis 22G5, showed significant inhibitory action against V. dahliae. Additional comparative genomic analyses and phenotypical assays confirmed that P. protegens XY2F4 and P. donghuensis 22G5 were the strains most efficient at protecting cotton plants against VW due to specific biological control products they produced. Importantly, we identified a significant efficacy of the natural tropolone compound 7-hydroxytropolone (7-HT) against VW. By phenotypical assay using the wild-type 22G5 and its mutant strain in 7-HT production, we revealed that the 7-HT produced by P. donghuensis is the major substance protecting cotton against VW. This study reveals that Pseudomonas specifically has gene clusters that allow the production of effective antipathogenic metabolites that can now be used as new agents in the biocontrol of VW.
由大丽轮枝菌引起的棉花黄萎病是一种毁灭性的土传病害，在全球范围内导致棉花和其他主要作物严重减产。在此，我们对从中国三大棉花产区采集的886份植物根际样本中分离得到的菌株进行了高通量筛选。筛选出了15株分布于不同细菌属、对大丽轮枝菌具有抑制活性的菌株。其中，两株假单胞菌菌株，即荧光假单胞菌XY2F4和东湖假单胞菌22G5，对大丽轮枝菌表现出显著的抑制作用。进一步的比较基因组分析和表型分析证实，荧光假单胞菌XY2F4和东湖假单胞菌22G5是保护棉花植株免受黄萎病侵害效率最高的菌株，因为它们产生了特定的生物防治产物。重要的是，我们确定了天然托酚酮化合物7-羟基托酚酮（7-HT）对棉花黄萎病具有显著疗效。通过使用野生型22G5及其7-HT产生突变株进行表型分析，我们发现东湖假单胞菌产生的7-HT是保护棉花免受黄萎病侵害的主要物质。这项研究表明，假单胞菌特别具有能够产生有效抗病原代谢物的基因簇，这些代谢物现在可作为棉花黄萎病生物防治的新药剂。
