【作者】 陈静鸿；

【导师】 葛绍荣；

【作者基本信息】 四川大学 ， 微生物学， 2007， 硕士

【摘要】 山葵，属十字花科多年生草本植物，产于日本富士山和台湾阿里山，是生产芥末的主要原料，沿海人们喜食生鱼片，以芥末为佐餐，被日本人民称为生活必需品。美国，加拿大，澳洲也有出口，因此市场销售量大。近年国外研究发现：山葵还具有杀菌防病、防腐利尿、发汗、清血、增进食欲、减脂和软化血管的功能，从而更增加了山葵的需求。因此，种植山葵有很好的经济社会效益。近年山葵已在大陆大量种植，我省青城、邛崃、雅安、乐山、绵阳、凉山等地区都建有种植基地，全国种植面积不下数十万亩。但其植株被一种黒根病感染，黑根病病原菌为一种丝状真菌——墨入菌(Phoma wasabiae Yokogi)引起。凡感染黒根病的山葵其产值下降50％以上。本研究用稀释分离法对成都、简阳、雅安等地区的农田、自然保护区的13个土壤样品进行放线菌和细菌的分离，共分离到放线菌119株，细菌67株。以山葵墨入菌为供试菌，采用点对峙培养筛选法对分离到的101株放线菌，57株细菌进行初筛，结果显示，对山葵墨入菌具有拮抗活性的放线菌38株，细菌10株。再通过打孔法复筛，得到产生抑菌圈最大的菌株SA2。根据传统的表型分类、生理分类，化学分类和现代16S rDNA序列分析的分子分类方法，即多相分类，对拮抗菌株SA2进行形态特征，生理生化特征分析以及16S rDNA序列分析。SA2为产芽胞细菌，周身鞭毛，芽胞中生，椭圆形，菌呈短杆状，菌体长1.9-2.8μm，宽0.6-1.1μm，具有运动性。LB培养基斜面30℃培养72h后，菌落呈乳白色，产生折皱。以16S rDNA序列为基础构建了包括14株相关种属细菌在内的系统发育树，其中，与芽孢杆菌属细菌有很高的同源性(92％-98.3％)，与苏云金芽胞杆菌(Bacillus thuringiensis)十分接近，序列相似性值98.3％。通过对平板对峙筛选的最强拮抗菌S11，S13，SA2，SA16进行室内盆栽试验，选取盆栽试验效果最好的菌株SA2进行田间试验。试验地选在成都市都江堰龙池镇的山葵种植场黑根病发病率在50％以上的场地。盆栽试验结果表明：SA2拮抗细菌菌株对山葵黑根病有良好的防治效果，对山葵黑根病的防效为85.57％。山葵种植1，3，5个月后，SA2对黑根病防效分别为74.12％，76.57％和78.98％，有较好的防治效果，且随时间的延长而增加。更多还原

【Abstract】 Wasabi is the main material of mustard’s production, growing in Fuji in Japan and Ali Mountain in Taiwan, which is necessity of Japanese. And it is exported to American, Canada and Australia. So there is a large demand for it. According to recent abroad studies, scientists found wasabi has the functions of sterilization, protection from illness, antisepsis, diuresis, diaphoresis, clearing blood, whetting appetite, decreasing fat and intenerating blood vessel. Therefor, the need of wasabi is increasing and it is a farm produce which will bring great profits. Recent years wasabi has cropped largely in mainland of China, there are fields of wasabi in Qingcheng, Leshan, Mianyang Sichuan province. But its individual plant is infected by phoma wasabiae Yokogi. If the plants were infected, the production value would reduce more than 50%.In our study, soil samples were gathered from wasabi fields in Oingcheng Chengdu, from which 101 actinomyces strains and 57 bacterial strains were isolated by tube dilution assay. With phoma wasabiae Yokogi as the tested stain, 38 antibiotic actinomyces stains and 10 bacterial strains were screened out by hyphal extension inhibition assay. And with the best antibiosis against phoma wasabiae Yokogi, bacterium SA2 strain was resceened from these strains through aperture-strikeing method.Traditional phenotype classification, chemotaxonology, and moderm molecular taxonology were used to study the strain SA2. It was identified as Bacillus thuringiensis by morphological, cultural physiological, biochemical characteristics, and 16S rDNA sequences analysis.Because of good antibiosis against phoma wasabiae Yokogi, SA2, S11, S13, SA16 were used to control the disease in the potted plant. The tests exhibited that SA2 had the highest control efficacy. And the next field text of SA2 indicated that SA2 could control the disease and the control efficacy reached 78.98%. The antifungal strains in the study were well worth developing and applying for the biocontrol of the disease..更多还原