苹果树腐烂病菌拮抗细菌筛选及鉴定

Screening and identification of antagonistic bacteria against Cytospora spp.

【目的】筛选对苹果树腐烂病菌具有较高抑菌活性的拮抗细菌,为苹果树腐烂病的生物防治提供理论依据.【方法】采用平板对峙法及生长速率法对分离自苹果树根际土壤和发病枝条的细菌进行筛选,并根据形态学与分子生物学对抑菌活性较高的菌株进行鉴定.【结果】共分离出13株细菌,其中QYTR-2对苹果树腐烂病菌的抑菌率最高,为82%,明显高于其他菌株.菌株QYTR-2不同稀释倍数的发酵滤液对苹果树腐烂病菌均有一定的抑制作用,其中5倍发酵滤液抑菌率最高,达92.23%.结合形态学和分子生物学技术鉴定该菌为嗜麦芽寡氧单胞菌Stenotrophomonas maltophilia.【结论】拮抗细菌QYTR-2(Stenotrophomonas maltophilia)对苹果树腐烂病菌具有良好的抑制作用,研究结果对丰富苹果树腐烂病的生防资源和开发利用生防菌株具有指导意义.

【Objective】 To screen the antagonistic bacteria with high antibacterial activity against Cytospora spp,and to provide a theoretical basis for the biological control of Cytospora spp.【Method】 Cytospora spp was considered as the target fungus to evaluate the biocontrol potential of antagonistic bacteria against Cytospora spp in vitro.The antagonistic effect of bacteria against Cytospora spp growth was determined by the method of confrontation and growth rat,and the screened antagonistic strain was identified by the method of morphology and molecular biology.【Result】 A total of 13 strains of bacteria were isolated,of which QYTR-2 had the highest inhibition rate against Cytospora spp,with a inhibition rate of 82%,which was significantly higher than that of other strains.The fermentation filtrates of different dilutions of strain QYTR-2 had certain inhibitory effects on Cytospora spp,and the inhibition rate of 5 times fermentation filtrate was the highest,reaching 92.23%.Identifying by morphology and molecular biology techniques indicated the bacteria is Stenotrophomonas maltophilia.【Conclusion】 The antagonistic bacteria Stenotrophomonas maltophilia QYTR-2 has a good inhibitory effect against Cytospora spp.