Mitsuboshi Masahiro, Kioka Yuuzou, Noguchi Katsunori, Asakawa Susumu
Tsukuba Research Institute, Katakura & Co-op Agri Corporation.
Microbes Environ. 2016 Sep 29;31(3):307-13. doi: 10.1264/jsme2.ME16052. Epub 2016 Aug 24.
Soil-borne diseases caused by pathogenic microorganisms are one of the main factors responsible for the decline in crop yields in farmlands. Pathogenic Fusarium oxysporum causes serious damage to various crops, and, thus, a feasible diagnostic method for soil-borne diseases is required. We herein examined a simple method to evaluate the suppressiveness of soil microorganisms against a pathogen by co-cultivating indigenous soil microorganisms and a pathogenic fungus (F. oxysporum f. sp. spinaciae). We inoculated F. oxysporum onto the center of agar medium plates mixed with a dilution series of a suspension of organic fertilizers or soil. After an approximately one-week cultivation, the growth degree of F. oxysporum was estimated based on the size of the colonies that formed on the plates. The growth degree of F. oxysporum significantly differed among the organic fertilizers tested, indicating the usefulness of the method for evaluating suppressiveness by organic fertilizers. Differences in the growth degrees of F. oxysporum were associated with the incidence of disease in spinach on soil treated with organic fertilizers and inoculated with a pathogenic F. oxysporum strain. These results suggested that this method provides some useful information on the suppressiveness of organic fertilizers and soil against Fusarium wilt.
由病原微生物引起的土传病害是导致农田作物产量下降的主要因素之一。致病性尖孢镰刀菌对各种作物造成严重损害，因此，需要一种可行的土传病害诊断方法。我们在此研究了一种简单的方法，通过将本地土壤微生物与致病真菌（尖孢镰刀菌菠菜专化型）共培养来评估土壤微生物对病原体的抑制作用。我们将尖孢镰刀菌接种到与有机肥料或土壤悬浮液稀释系列混合的琼脂培养基平板中央。经过大约一周的培养后，根据平板上形成的菌落大小估计尖孢镰刀菌的生长程度。在所测试的有机肥料中，尖孢镰刀菌的生长程度存在显著差异，表明该方法可用于评估有机肥料的抑制作用。尖孢镰刀菌生长程度的差异与用有机肥料处理并接种致病尖孢镰刀菌菌株的土壤上菠菜的发病率有关。这些结果表明，该方法为有机肥料和土壤对枯萎病的抑制作用提供了一些有用信息。
