蓝莓枝枯病拮抗细菌HMQAU140045的鉴定和抑真菌活性

以蓝莓毛色二胞枝枯病菌假可可毛色二胞Lasiodiplodia pseudotheobromae为靶标菌，通过稀释平板法从山东青岛的蓝莓种植园根际土壤中分离出20株细菌，采用对峙平板法和菌丝生长速率法筛选得到一株对靶标菌具有明显抑制效果的拮抗菌株HMQAU140045，采用凹玻片法和菌丝生长速率法测定该菌株发酵滤液对靶标菌孢子萌发和菌丝生长的影响。结果表明，稀释50倍的发酵滤液的抑制率可达100%。离体枝条试验结果表明，发酵液不同组分对蓝莓毛色二胞枝枯病的防治效果均可达90%以上。菌丝生长速率法测定结果表明，该菌株抑真菌谱广，对包括4种蓝莓枝枯病菌在内的15种植物病原真菌具有良好的拮抗作用。通过形态观察、生理生化特性以及gyrB的序列分析，确定该菌株为解淀粉芽孢杆菌Bacillus amyloliquefaciens。试验结果表明，解淀粉芽孢杆菌菌株HMQAU140045具有较好的抑真菌活性。

Identification and antifungal activity of antagonistic bacterium HMQAU140045 against blueberry twig blight

Twenty strains of bacteria were isolated by the plate dilution method from the rhizosphere soil collected from the blueberry plantations in Qingdao, Shandong. Among them, a strain, HMQAU140045, with obvious inhibition effect on the target fungus, blueberry Lasiodiplodia twig blight pathogen-Lasiodiplodia pseudotheobromae, was discovered by the plate confrontation method and mycelial growth rate method. With the concave slide method and mycelial growth rate method, the effects of HMQAU140045 fermentation filtrate on the spore germination and mycelial growth of the target fungus were measured. The results showed that the inhibition rate of the 50 times diluted fermentation filtrate could reach 100%. The result of the detached twig experiment indicated that the control efficacies of different components against blueberry Lasiodiplodia twig blight in the fermentation broth are all above 90%. Bioassay results obtained using the mycelial growth rate method demonstrated that the strain was of broad antifungal spectrum, with obvious antifungal activity against fifteen plant pathogenic fungi, including four blueberry twig blight pathogens. Based on the morphological observation, physiological and biochemical characteristics, and the sequence analysis of gyrB, strain HMQAU140045 was identified as Bacillus amyloliquefaciens. These experimental results demonstrated that the strain HMQAU140045 of Bacillus amyloliquefaciens had good antifungal activity.