Development of agricultural materials with super microbial activities

由于农药污染带来的严重环境问题，利用微生物防治植物病害将是世纪的重要课题。我们分离了大约一千个荧光假单胞菌，并选择了对弯草根表现出最高亲和力的菌株。最终获得荧光假单胞菌菌株HP 72。将该菌株应用于草坪草上，可完全控制草坪草褐斑病的发生。通过RAPD PCR技术可以分离到对该菌株特异性较强的DNA片段，并可通过FIA-PCR方法对该菌株进行田间鉴定。该菌株对海湾球场草坪真菌病害有较好的防治效果。该菌株能在高尔夫球场土壤中存活很长时间，占总荧光假单胞菌的比例很高。但该菌株在33℃以上不能生长，因此在夏季其种群数量和占总荧光假单胞菌的比例下降。然而，人民 ...更多信息 秋天离子会自动恢复。在田间试验中，当HP 72的种群数量较高时，真菌病害几乎被完全控制。从液体培养物中纯化了一种抗真菌化学物质，并鉴定为Phl。然后，我们试图揭示疾病控制的原因。我们在任何种类的琼脂培养基上制备了四个不产生Phl的突变体。检测了四种突变体的疾病控制活性。尽管这4个突变体不能产生抗真菌化学物质，但它们都能控制褐斑病。然后，对四种菌株的植物生长促进活性进行了检查。这4个突变体都表现出了植物生长促进活性。因此，植物促生活性对病害防治的重要性远远超过化学制剂。测试菌株HP 72在其它植物中的存活。该菌株在茄子和番茄根部很快消失。该菌株在大麦和小麦的根上存活较长时间，但最终在4至5周后消失。作为本研究的第二个主题，我们专注于AM真菌。我们用分子生物学方法揭示了土壤和植物中AM真菌的多样性，并从各种系统谱系中筛选出超级AM真菌。少

Plant disease control by microorganisms will be very important in 21st century because agricultural chemicals are causing serious environmental problems. We isolated approximately one thousands of fluorescent Pseudomonads, and selected strains which showed the most highest affinity to the root of bent grass. Finally, we got Pseudomonas fluorescens strain HP72. When this strain was applied on the bent grass, the brown patch disease was completely countrolled. By the RAPD PCR we could isolate DNA fragment very specific to this strain, and we could enumerate the strain in the fields by the FIA-PCR method. The strain was very effective to control fungal diseases of gulf course turf. The strain can survive very long periods in the soil of golf course and ratio to the total fluorescent pseudomonas was very high. However, the strain do not grow at higher temperature than 33℃, and therefore, in summer the population and ratio to the total fluorescent pseudomonas came down. However, the populat … More ion recovers automatically in autumn. In the field experiment, when the population of HP72 was high, the fungal diseases were almost completely controlled. An antifungal chemical was purified from the liquid culture and identified as Phl. Then, we tried to reveal what causes disease control. We made four mutants which do not produce Phl out any kinds of agar media. Disease controlling activity was examined for the four mutants. In spite of inability of producing antifungal chemical, the four mutants could control the brown patch disease. Then, plant growth promoting activity was examined for the four strains. The four mutants showed plant growth promoting activity. Therefore, the plant growth promoting activity is more important for disease control that the antifungal chenical production. The survival of the strain HP72 was tested for other plants. The strain disappeared very quickly on the roots of egg plant and tomato. The strain survived longer on the roots of barley and wheat, but finally disappeared after four to five weeks, The affinity of plant roots of HP72 is considered to be restricted to bent grass. As second subject of this study, we focused on AM fungi. We revealed the diversity of AM fungi in soils and plants by molectular biological methods, and we are selecting super AM fungi from the various kinds of phylogenetic lineages. Less