FC02菌株鉴定及对链格孢菌的拮抗效果

Identification of strain FC02 and its antagonistic effect against Alternaria alternate

为明确菌株FC02对烟草赤星病病原菌[链格孢菌(Alternaria alternata)]的拮抗效果,通过菌落形态观察、生理生化鉴定和系统发育树分析鉴定菌株种类,采用对峙培养法分析该菌株对链格孢菌的抑制效果,测定菌株发酵滤液对链格孢菌的菌丝生长抑制率及其在不同温度、pH值、紫外线照射时间、储藏时间处理中的抑菌稳定性,并通过盆栽试验测定菌株发酵液对烟草赤星病的防治效果。结果表明:(1)菌株FC02为贝莱斯芽孢杆菌(Bacillus velezensis)。(2)对峙培养时,链格孢菌细胞壁破裂,细胞膜内陷,部分细胞器解体,菌丝体皱缩变形,无孢子萌发,链格孢菌的菌丝生长抑制率为78.70%。(3)菌株FC02发酵滤液对菌丝生长抑制率为81.19%且在不同温度(25~120℃)、pH值(7~11)、紫外线照射时间(5~45 min)、储藏时间(0~60 d)处理中均有良好的抑菌稳定性。(4)盆栽试验中菌株FC02发酵液(1×10^(7)cfu/mL)对烟草赤星病的防治效果为71.40%,与1×10^(9)cfu/g枯草芽孢杆菌可湿性粉剂对烟草赤星病的防治效果(68.35%)无显著(P<0.05)差异。

To clarify the antagonistic effect of strain FC02 against the pathogen of tobacco brown spot disease(Alternaria alternata),the strain was identified by colonial morphological observation,physiological and biochemical identification and phylogenetic tree analysis.The inhibitory effect of strain FC02 on Alternaria alternata was analyzed by confrontation culture method,and the inhibition rate of the fermentation filtrate on hyphal growth of Alternaria alternata and its antibacterial stability under different treatments of varying temperature,pH value,ultraviolet irradiation time and storage time were determined.The control efficiency of the fermentation broth on tobacco brown spot disease was determined by pot experiments.The results showed that:1)Strain FC02 was Bacillus velezensis.2)During confrontation culture,the cell wall of Alternaria alternata was ruptured,the cell membrane was invaginated,some organelles disintegrated,the mycelium shrunk and deformed,and no spore was germinated.The inhibition rate of mycelial growth of Alternaria alternata was 78.70%.3)The inhibition rate of the fermentation filtrate of strain FC02 on mycelial growth was 81.19%,and it had good antibacterial stability in different treatments of temperature(25-120℃),pH value(7-11),ultraviolet irradiation time(5-45min)and storage time(0-60 d).4)In the pot experiment,the fermentation broth of strain FC02(1×10^(7)cfu/mL)showed a control efficiency of 71.40%against tobacco brown spot disease,which was not significantly(P<0.05)different from the control efficiency(68.35%)by 1×10^(9)cfu/g Bacillus subtilis wettable powder.