Study of control systems for soil-borne diseases by indigenous microbial diversity

在植物病害的防治中，利用天然安全的微生物作为生物防治体系备受期待。然而，这种疾病控制系统往往声称其不一致的效果。因此，我们进行了一系列的实验，旨在通过利用土著微生物多样性开发安全和一致的土传疾病防治系统。本研究项目取得的具体成果如下。（1）土传病害与土壤微生物多样性的关系分析：在大田条件下，采用PCR-DGGE、FAME和CLPP技术监测土壤微生物区系的变化，验证了前期盆栽试验中以野燕麦作绿色肥料对番茄黄萎病的防治效果。另一方面，小麦麸皮配水施用对番茄枯萎病和青枯病的抑制效果也较好，例如，“土壤减少法” ...更多信息 根据病原体密度以及兼性厌氧菌来研究该方法。通过克隆DGGE条带鉴定细菌，进一步阐明了后者。此外，采用HPLC测定了该事件期间产生的有机酸。（2）土传病害与土壤共生丛枝菌根（AM）多样性的关系分析：AM不仅能提供磷等无机营养物质，还能保护植物免受各种环境胁迫。因此，为了阐明AM多样性土著土壤和抑制土传病害之间的关系，AM多样性定殖植物根系使用脂肪酸甲酯（FAME）。具体地，FAME的组分源自AM，例如，16：1ω5在茄子健康根和发病根中的含量比较。结果表明，茄子黄萎病病根与健康根的FAME组分差异较大，表明土壤中AM真菌对茄子黄萎病的发生有一定的影响。少

In controlling plant diseases, utilization of natural and safe microorganisms for biological control system is highly anticipated. However, this disease control system is often claimed for its inconsistent effect. Therefore, we conducted a series of experiments aiming at development of disease control systems pertaining safe and consistent efficacy for soil-borne diseases by utilizing indigenous microbial diversity. Specific results obtained in this research projects are as follows. (1)Analysis of relationships between soil-borne diseases and microbial diversity indigenous to soil : application of wild oats as a green manure, which was effective on controlling Verticillium wilt of tomato in previous pot experiments, was verified under a field condition in monitoring soil microfloral changes with PCR-DGGE, FAME, and CLPP. On the other hand, suppression of Fusarium wilt and Bacterial wilt of tomato by applying wheat-bran with irrigation, i.,e., ‘soil disinfestation with soil reduction me … More thod' was investigated in terms of pathogen densities as well as facultative anaerobic bacteria. The latter was further elucidated with identifying bacteria by cloning the DGGE bands. In addition, organic acids produced during this event were determined with HPLC. (2)Analysis of relationships between soil-borne diseases and symbiotic arbuscular-mycorrhizae (AM) diversity indigenous to soil : AM are known to protect plant from various environmental stresses as well as provision of inorganic nutrients such as phosphorus. Therefore, to elucidate the relationships between AM diversity indigenous to soil and suppression of soil-borne diseases, the AM diversity colonizing plant roots was determined using fatty acid methyl ester(FAME). Specifically, components of FAME originated from AM e.g., 16:1ω5 were compared between healthy and diseased (infected by Verticillium wilt) roots of eggplant. The results indicated that the FAME components of diseased roots substantially differed from those of healthy roots, suggesting that AM fungi indigenous to soil influences on the disease occurrence of Verticillium wilt of eggplant. Less