番茄灰霉病拮抗芽孢杆菌LW-6-1的筛选、鉴定及抑菌活性研究

Screening,identification and antibacterial activity of antagonistic bacteria LW-6-1 against Botrytis cinerea

【目的】从福建、四川、陕西等地耕作土壤中筛选对番茄灰霉病有较强生防效果的拮抗芽孢杆菌。【方法】随机采集福建、四川、陕西等地耕作土壤样品30份,采用平板稀释法从中分离芽孢杆菌,以番茄灰霉病菌、稻瘟病菌、辣椒疫霉病菌、苹果轮纹病菌、小麦根腐病菌、棉花枯萎病菌为靶标菌筛选拮抗芽孢杆菌;检测拮抗芽孢杆菌菌株无菌发酵液对供试病原真菌菌丝生长、孢子萌发、菌丝形态的影响;通过形态学特征、生理生化特征及16SrDNA序列分析,对筛选出的拮抗菌株进行鉴定。【结果】从采集的30份土壤样品中分离得到273株芽孢杆菌,经病原真菌定向筛选后,得到1株对番茄灰霉病菌、稻瘟病菌、辣椒疫霉病菌、苹果轮纹病菌、小麦根腐病菌、棉花枯萎病菌有较强生防效果的芽孢杆菌LW-6-1,LW-6-1菌株无菌发酵液对番茄灰霉病菌和稻瘟病菌菌丝生长的抑制效果较好,菌丝生长抑制率分别为95.34%和92.56%,EC50分别为10.18和10.84mL/L;对抑制番茄灰霉病菌和稻瘟病菌孢子萌发的抑制率分别为93.98%和92.09%,EC50分别为2.03和2.67mL/L。经鉴定,LW-6-1为甲基营养型芽孢杆菌Bacillus methylotrophicus。【结论】筛选到的拮抗芽孢杆菌LW-6-1对番茄灰霉病有较强的生防效果,能显著抑制番茄灰霉病菌的生长。

【Objective】A strong effective bio-control bacillus for Botrytis cinerea was selected in soil from Fujian,Sichuan,Shaanxi and other provinces.【Method】Random samples were collected from farming soil,bacillus was separated using plant dilute,and several fungal pathogens including B.cinerea,Pyricularia oryzae,Phytophthora capsici Leonian,Physalospora piricola,Bipolaris sorokiniana,and Fusarium oxysporum f.sp.vasinfectum were selected as the indicator bacteria.Effects of bacillus sterile broth on the mycelial configuration,the mycelium growth,and the spore germination of pathogenic fungi were determined.The antagonistic bacillus was identified based on morphological,physiological and biochemical characteristics,and 16S rDNA phylogenetic analysis.【Result】273 strains bacteria were isolated from 30 soil samples.LW-6-1,a bacillus with strong bio-control effects on B.cinerea,P.oryzae,P.capsici Leonian,P.piricola,B.sorokiniana,and F.oxysporum f.sp.vasinfectum was obtained.The fermented liquid of strain LW-6-1 had great inhibition effect on mycelium growth of B.cinerea and P.oryzae,with inhibition rates of 95.34% and 92.56%,and EC50 values of 10.18 and 10.84 mL/L,respectively.The inhibition rates on spore germination were 93.98% and 92.09% and EC50 values were 2.03 and 2.67 mL/L,respectively.Strain LW-6-1 was identified as Bacillus methylotrophicus.【Conclusion】Bacterial LW-6-1 had strong biological control effects against B.cinerea.