Suppression of damping-off disease in host plants by the rhizoplane bacterium Lysobacter sp strain SB-K88 is linked to plant colonization and antibiosis against soilborne peronosporomycetes
Suppression of damping-off disease in host plants by the rhizoplane bacterium Lysobacter sp strain SB-K88 is linked to plant colonization and antibiosis against soilborne peronosporomycetes
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DOI：
10.1128/aem.71.7.3786-3796.2005
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发表时间：
2005-07-01
影响因子：
4.4
通讯作者：
Tahara, S
中科院分区：
文献类型：
--
作者：
Islam, MT;Hashidoko, Y;Tahara, S
我们以前证明，从根际细菌溶杆菌属菌株SB-K88的黄霉素A抑制由腐霉属引起的甜菜立枯病。本研究主要研究溶杆菌SB-K88菌株对黄瓜立枯病病原菌丝囊霉的定殖和侵染方式。扫描电子显微镜分析2周龄甜菜幼苗从种子接种SB-K88揭示密集的殖民化根表面和特征的垂直模式溶杆菌殖民化可能产生通过发展的极性，刷状菌毛。在定殖区域，在根表面观察到明显包裹根的透明膜和小菌落。该溶杆菌菌株还有效地定殖于几种植物的根，包括菠菜、番茄、拟南芥和苋。从先前用溶杆菌属菌株SB-K88处理的甜菜和菠菜种子生长的植物显示出对由A.螺旋状。有趣的是，A. Cochhoides在暴露于SB-K88细胞悬浮液、SB-K88的无细胞上清液或纯黄杆菌素A（MIC，0.01 μ g/ml）后1分钟内变得不动。在所有情况下，在存在抑制因子的情况下，在30分钟内发生裂解。结果表明溶杆菌SB-K88菌株对A. cochlioides，抑制立枯病。此外，溶杆菌属菌株SB-K88的这种抑制作用可能是由于在宿主植物的根面处的寄生和特征性生物膜形成的组合。
We previously demonstrated that xanthobaccin A from the rhizoplane bacterium Lysobacter sp. strain SB-K88 suppresses damping-off disease caused by Pythium sp. in sugar beet. In this study we focused on modes of Lysobacter sp. strain SB-K88 root colonization and antibiosis of the bacterium against Aphanomyces cochlioides, a pathogen of damping-off disease. Scanning electron microscopic analysis of 2-week-old sugar beet seedlings from seeds previously inoculated with SB-K88 revealed dense colonization on the root surfaces and a characteristic perpendicular pattern of Lysobacter colonization possibly generated via development of polar, brush-like fimbriae. In colonized regions a semitransparent film apparently enveloping the root and microcolonies were observed on the root surface. This Lysobacter strain also efficiently colonized the roots of several plants, including spinach, tomato, Arabidopsis thaliana, and Amaranthus gangeticus. Plants grown from both sugar beet and spinach seeds that were previously treated with Lysobacter sp. strain SB-K88 displayed significant resistance to the damping-off disease triggered by A. cochlioides. Interestingly, zoospores of A. cochhoides became immotile within 1 min after exposure to a SB-K88 cell suspension, a cell-free supernatant of SB-K88, or pure xanthobaccin A (MIC, 0.01 mu g/ml). In all cases, lysis followed within 30 min in the presence of the inhibiting factor(s). Our data indicate that Lysobacter sp. strain SB-K88 has a direct inhibitory effect on A. cochlioides, suppressing damping-off disease. Furthermore, this inhibitory effect of Lysobacter sp. strain SB-K88 is likely due to a combination of antibiosis and characteristic biofilm formation at the rhizoplane of the host plant.