【摘要】 【背景】香蕉枯萎病是由尖孢镰刀菌古巴专化型(Fusarium oxysporum f. sp. cubense,Foc)引起的一种真菌毁灭性土传病害,近年来施用生防菌被认为是一种有效的防治手段。【目的】从香蕉根际土壤中分离筛选具有良好防效的生防菌,并通过优化培养基及发酵条件,提高生防菌数量及抑菌效率。【方法】以福建省漳州蕉园中根际土壤为样品,以香蕉枯萎病致病菌(4号生理小种)为指示菌,通过稀释涂布、平板对峙法筛选得到一株具有较强抑菌活性的拮抗菌株HQB-1。通过形态观察、生理生化检测及16SrRNA基因序列分析,初步鉴定其种属,并采用单因素试验及正交设计优化菌株的发酵培养基及发酵条件。【结果】初步鉴定HQB-1菌株为Burkholderiastagnalis;最适培养基为:牛肉膏5.0 g/L,酵母浸粉10.0 g/L,NaCl 5.0 g/L;最佳发酵条件为:温度27°C,pH 7.0,转速200 r/min,接种量1%,培养时间36 h。【结论】使用该条件培养获得的有效活菌数及抑菌率较优化前明显提高,其中OD600由优化前的1.251提高至1.881,抑菌率由优化前的9.18%提高至34.60%。更多还原

【Abstract】 [Background] Banana wilt is a fungal devastating soil-borne disease caused by Fusarium oxysporum f. sp. cubense(Foc). In recent years, the application of biocontrol bacterium is an effective means of prevention and control. [Objective] Biocontrol bacteria with good control effect were isolated and screened from the rhizosphere soil of banana, and the number of biocontrol bacteria and antibacterial efficiency were improved by optimizing the medium and fermentation conditions. [Methods] The rhizosphere soil was collected from orchard in Zhangzhou, Fujian province. The pathogen of Foc Tropical Race 4(Foc 4) was used as indicator fungus. An antagonistic strain named HQB-1 with strong antifungal activity was isolated by dilution coating and plate confrontation method. Strain HQB-1 was identified by morphological observation, physiological and biochemical experiments and 16 S rRNA gene sequence analysis. The fermentation conditions were optimized by single factor experiment and orthogonal experiment design. [Results] Strain HQB-1 was identified as Burkholderia stagnalis, the optimized medium was beef extract 5.0 g/L, yeast extract 10.0 g/L, NaCl 5.0 g/L, and the optimal culture temperature at 27 °C, pH 7.0, rotation speed 200 r/min, inoculation amount 1%, and the culture time 36 h. [Conclusion] The number of effective viable cells and the inhibition rate were, improved significantly than before. The OD600 was increased from 1.251 to 1.881, and the inhibition rate was from9.18% to 34.60%.更多还原