【摘要】 [目的]从蚯蚓粪中筛选广谱拮抗植物病菌的细菌并应用于生物防治,同时对它的抑菌机制进行初步探究。[方法]以10种病原真菌为靶菌,采用梯度稀释法和平板对峙法对蚯蚓粪中的拮抗菌进行初筛和复筛,并结合形态学特征、生理生化指标和16S rDNA基因序列对拮抗菌进行初步鉴定;采用生长速率法测定菌株及其脂肽类提取物的拮抗活性;通过平板倒扣法测定菌株产挥发性物质(VOCs)抑制病原菌菌丝生长的效果。[结果]筛选出拮抗水稻纹枯病菌、黄瓜枯萎病菌、桃溃疡病菌和灰霉病菌的拮抗细菌分别为12、21、3和3株。其中,菌株M29(Gen Bank登录号:KU870670)能够有效且强烈地抑制灰霉等10种病原菌,对水稻纹枯病菌、大丽轮枝病菌和灰霉病菌的抑制率分别高达95%、91%和89%。结合形态学特征、生理生化指标和16S rDNA基因序列分析,初步鉴定菌株M29为枯草芽孢杆菌(Bacillus subtilis)。菌株M29产生的脂肽类粗提取物对桃溃疡病菌的抑制率高达97%;产生的VOCs对大丽轮枝病菌的抑制率达65%,且VOCs不仅能明显抑制烟曲霉孢子的生长,还可抑制多种病原菌色素的产生。[结论]枯草芽孢杆菌M29菌株具有较高的广谱拮抗病原真菌的能力,在植物真菌病害生物防控中具有潜在的应用价值。更多还原

【Abstract】 [Objectives]An antagonistic bacterium,which had broad-spectrum antagonistic effect on pathogenic fungi,was isolated from vermicompost. We further tried to reveal its antibiotic mechanism to understand how it was used for bio-control. [Methods]Ten plant pathogenic fungi were used as the target fungi to isolate the antagonistic bacteria from vermicompost according to the methods of gradient dilution and dural culture. Then,the antagonistic bacteria were identified based on its morphological,physiological and biochemical characteristics and 16 S rDNA gene sequence analysis. The antimicrobial activity of antifungal lipopeptides derived from antagonistic bacteria was examed with mycelium growth rate method,and the inhibition ratio of volatile substances( VOCs) to hyphal growth was measured by plate back-off method. [Results]Results showed that 12 bacterial strains against Rhizoctornia solani,21 strains against Fusarium oxysporum f. sp. cucumerinum,3 strains against Phomopsis amygdali,and 3 strains against Botrytis cinerea were isolated. Among them,the strain M29( Gen Bank accession number: KU870670) had effective and strong inhibition of Botrytis cinerea and other 9 pathogenic fungis,with 95% inhibition rate on mycelium growth of Rhizoctornia solani,and 91% inhibition rate on,and 89% inhibition rate on Verticillium dahliae and Botrytis cinerea respectively. The strain M29 was identified as Bacillus subtilis according to its morphological,physiological and biochemical characteristics and the results of 16 S rDNA gene sequence analysis.Besides,the antifungal lipopeptides and volatile substances derived from the strain M29 had inhibition rate of 97% against the Phomopsis amygdali and 65% against the Verticillium dahlia,respectively. VOCs had an obvious inhibition on the growth of Aspergillus fumigatus and the production of pigment generated by various pathogenic fungi. [Conclusions]The strain M29 had potential bio-control value of broad-spectrum antagonistic effect on soil-born plant pathogenic fungi.更多还原