| 摘要: |
| 【目的】从多年耕作的番茄大棚土壤中筛选对番茄疫霉根腐病有较强生防效果的拮抗细菌。【方法】随机采集多年耕作的番茄大棚土壤样品30份，采用平板稀释法从中分离细菌，以辣椒疫霉病菌、番茄灰霉病菌、烟草黑胫病菌、小麦根腐病菌、棉花枯萎病菌、稻瘟病菌为靶标菌筛选拮抗菌；通过形态学特征、生理生化特征及16S rDNA序列分析对筛选出的拮抗菌株进行鉴定。检测拮抗菌株无菌发酵液对供试病原真菌菌丝生长、孢子萌发、菌丝形态的影响及对番茄疫霉根腐病的盆栽防效。用饱和度分别为10%，20%，25%，30%，35%，40%，50%，60%，70%，80%，90%和100%硫酸铵对拮抗菌株无菌发酵液进行沉淀，测定不同饱和度硫酸铵沉淀物的抑菌活性。【结果】从采集的30份土壤样品中分离得到253株细菌，经病原真菌定向筛选后，得到1株对辣椒疫霉病菌、番茄灰霉病菌、烟草黑胫病菌、小麦根腐病菌、棉花枯萎病菌、稻瘟病菌有较强生防效果的细菌FC12-05，经鉴定FC12-05为西姆芽孢杆菌(Bacillus siamensis)。FC12-05菌株无菌发酵液对辣椒疫霉病菌和番茄灰霉病菌菌丝生长的抑制效果较好，菌丝生长抑制率分别为95.02%和92.43%，EC50分别为10.14和10.78 mL/L；对抑制辣椒疫霉病菌和番茄灰霉病菌的孢子萌发抑制率分别为94.60%和92.45%，EC50分别为2.09和2.53 mL/L；对番茄疫霉根腐病的盆栽防治效果高达93.50%。在硫酸铵饱和度为10%～25%时，获得的抑菌物质对辣椒疫霉病菌均有抑菌活性，其中硫酸铵饱和度为20%时获得的抑菌物质对辣椒疫霉病的抑菌活性较高，抑菌圈直径达19.33 mm；硫酸铵饱和度≥30%时，无沉淀析出，对辣椒疫霉病菌无抑菌活性。【结论】筛选到的拮抗细菌FC12-05对番茄疫霉根腐病有较强的生防效果，能显著抑制番茄疫霉根腐病菌的生长。 |
| 关键词: 番茄疫霉根腐病 辣椒疫霉病菌 抑菌活性 |
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| 基金项目:高等学校学科创新引智计划项目（B07049）；国家“863”项目“特殊微生物资源的研究和利用”（2007AA021503）；中国烟草有害生物普查项目（KJ-2010-04） |
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| Screening,identification and antibacterial activity of antagonistic bacteria FC12-05 against phytophthora root rot of tomato |
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| Abstract: |
| 【Objective】The strong effective biocontrol bacteria for phytophthora root rot of tomato were selected from greenhouse tomato farming soil for several years.【Method】Random samples were conducted from greenhouse tomato farming soil for many years,separated the bacteria used plant dilute,selected directionally with several fungal pathogens such as P.capsici Leonian,Botrytis cirerea,Phytophthora nicotianae,Bipolaris sorokiniana,Fusarium oxysporum f.sp.vasinfectum,Pyricularia oryzae as the indicator bacteria;We identified the antagonistic bacteria based on morphological,physiological and biochemical characteristics,and 16S rDNA phylogenetic analysis;determined the effect of the mycelial configurationthe of pathogenic fungi,the mycelium growth of pathogenic fungi,the spore germination on pathogenic fungi spores broth germination and the control efficacy of bonsai experiment in greenhouse with the sterile fermentation of antagonistic bacteria.Then we deposited the sterile fermentation of antagonistic bacteria with ammonium sulfatem,which saturation concentration respectively was 10%,20%,25%,30%,35%,40%,50%,60%,70%,80%,90% and 100%,and tested the antifungal activity of ammonium sulfate precipitation of the antagonists.【Result】253 strains bacterium were isolated from 30 soil samples,FC12-05,a strong effect of bacterial on Phytophthora capsici Leonian,Botrytis cirerea,Phytophthora nicotianae,Bipolaris sorokiniana,Fusarium oxysporum f.sp.vasinfectum,Pyricularia oryzae;The strain FC12-05 was identified as Bacillus siamensis.The fermented liquid of strain FC12-05 had great inhibition effect on mycelium growth of P.capsici Leonian and Botrytis cinerea,the inhibition rate of mycelium growth was 95.02% and 92.43%;the EC50 values was 10.14 and 10.78 mL/L;the inhibition rate of spore germination was 94.60% and 92.43%;the EC50 values was 2.09 and 2.53 mL/L;the control effect of FC12-05 strain on phytophthora root rot of tomato was up to 93.50%;The antifungal metabolite by stain FC12-05 precipitated by 20% ammonium sulfate showed the most effective inhibition toward P.capsici Leonian,the inhibition zone diameter was up to 19.33 mm;there was no deposit when the saturation concentration was ≥30%,the fermented liquid had no activity of antagonistic bacteria against P.capsici Leonian.【Conclusion】Bacterial FC12-05 against phytophthora root rot of tomato has a strong effect on biological control,showing a significantly inhibited effect on tomato growth of phytophthora root rot. |
| Key words: phytophthora root rot of tomato Phytophthora capsici Leonian antibacterial activity |
