黄瓜土传病害拮抗细菌的筛选、鉴定及生防特性研究

为了有效防治黄瓜的土传病害，本文从黄瓜根际土壤中分离得到256株细菌，利用平板对峙试验筛选到一株拮抗菌ZM-1。通过形态、生理生化和分子生物学方法对菌株进行鉴定，测定菌株产生的抑菌物质。通过正交实验法与单因素法对菌株进行发酵优化，并通过盆栽试验测定菌株防病能力。结果表明，菌株ZM-1为铜绿假单胞菌Pseudomonas aeruginosa，该菌对黄瓜枯萎病菌Fusarium oxysporum f. sp. cucumebrium 和黄瓜疫病菌Phytophthora drechsleri的抑制率分别为62.80%和65.58%。该菌株可以产生纤维素酶、铁载体等多种抑菌物质。经过最佳发酵优化，菌株发酵液菌含量可达到1×10¹⁰ cfu/mL以上。最适发酵培养基配方为蔗糖5 g/L、胰蛋白胨10 g/L、K₂HPO₄ 10 g/L，发酵条件温度25 ℃、pH 7.5、时间48 h、接种量2%。盆栽试验表明，菌株ZM-1对黄瓜枯萎病和黄瓜疫病的防效分别为53.97%和51.11%。本研究表明拮抗菌ZM-1在防治黄瓜土传病害方面具有开发应用的潜力。

Screening,Identification and Biocontrol Characteristics of Antagonistic Bacteria against Cucumber Soil-borne Diseases

In order to effectively control soil-borne diseases of cucumber, 256 strains of bacteria were isolated from the rhizosphere soil of cucumber, and an antagonistic strain ZM-1 was screened by the plate confrontation method. Based on physiological, biochemical and molecular biological analysis, the strain ZM-1 was identified to be Pseudomonas aeruginosa. The inhibition rate of the strain against Fusarium oxysporum f. sp. cucumebrium and Phytophthora drechsleri were 62.80% and 65.58%, respectively. The strain can produce a variety of antibacterial substances, such as cellulase, siderophore and so on. The fermentation optimization of the strain was carried out by orthogonal experiment method and single factor method. After optimization, the bacterial amount in the fermentation broth of the strain can reach more than 1×10¹⁰cfu/ml. The optimal fermentation conditions were 5 g/L of sucrose, 10 g/L of tryptone, 10 g/L of K₂HPO₄, pH value of 7.5, continuous fermentation for 48 h, with 2% inoculation quantity under temperature of 25 ℃. Pot experiment showed that the relative control efficacies of strain ZM-1 against cucumber fusarium wilt and cucumber blight were 53.97% and 51.11%, respectively. The above results indicate that the antagonist strain ZM-1 has potential for development and application in the control of soil-borne diseases of cucumber.