【摘要】 为挖掘对烟草根黑腐病菌有较强拮抗效果，且可在烟株根部稳定定殖的生防菌资源，以烟草根黑腐病菌为靶标，利用稀释涂布法和平板对峙法分离筛选出高效拮抗活性菌株，对其进行系统发育分析以及粗脂肽抑菌活性检测；并运用PCR技术检测拮抗细菌的脂肽编码基因，利用趋化性及生物膜成膜等试验研究烟草根系分泌物及其产生的各种有机酸对拮抗菌根部定殖的影响。结果表明：从烟草根际土壤中分离得到两株Thielaviopsis basicola高效拮抗菌株S2-1和SNSY15-5,分子鉴定表明，S2-1和SNSY15-5均为芽孢杆菌属细菌；拮抗菌S2-1和SNSY15-5脂肽粗提物对T.basicola毒力较强，EC₅₀值分别为1.93和2.56 mg·mL^-1,SNSY15-5含有参与脂肽类家族细菌素（bmyB）、生物素操纵子（bioA）和假定蛋白（yngG）合成的基因；S2-1菌株中含有参与脂肽类家族生物素操纵子（bioA）合成的基因；烟草品种K326根系分泌物产生的苹果酸对S2-1和SNSY15-5有较强的吸引作用，S2-1和SNSY15-5在苹果酸中的数量分别达到63.35×10⁴ CFU·mL^-1和42.35×10⁴ CFU·mL^-1,K326烟草根系分泌物及其草酸可促进S2-1生物膜形成，而K326烟草根系分泌物及其柠檬酸则促进SNSY15-5生物膜形成。该研究结果为开发效果稳定的微生物菌剂提供理论基础。更多还原

【Abstract】 In order to explore the biocontrol bacteria resources which had the strong antagonistic effect on tobacco black root rot and could stably colonize the tobacco roots, taking Thielaviopsis basicola as the target, the highly antagonistic strains were isolated and obtained by dilution-plate method and plate confrontation method, and the phylogenetic analysis and antibacterial activity of crude lipopeptide of antagonistic strains were carried out; then the genes coding lipopeptide of antagonistic strains were analyzed by PCR, the effects of K326 tobacco root exudates and various organic acids on root colonization of antagonistic bacteria were studied by chemotaxis and biofilm formation tests. Results indicated that the effective antagonistic strains S2-1 and SNSY15-5 were isolated from tobacco rhizosphere soil, and they were Bacillus microorganisms. The crude lipopeptides of the S2-1 and SNSY15-5 were high virulent to Thielaviopsis basicola, and the EC₅₀ of them was 1.93 and 2.56 mg·mL^-1, respectively. SNSY15-5 had the biocontrol marker genes involved in the synthesis of bmyB, bioA and yngG, while S2-1 had the biocontrol marker gene involved in the synthesis of bioA. Malic acid produced by K326 root exudates had better attraction to S2-1 and SNSY15-5, and the amount of S2-1 and SNSY15-5 in malic acid reached 63.35×10⁴ CFU·mL^-1 and 42.35×10⁴ CFU·mL^-1, respectively. The biofilm formation of S2-1 could be promoted by the K326 root exudates and oxalic acid, while the biofilm formation of SNSY15-5 could be promoted by the K326 root exudates and citric acid. The research results provide a theoretical basis for developing microbial agent with stable effect.更多还原