小麦根围禾谷丝核菌拮抗菌的鉴定、抗生素产生和根部定殖研究

Identification,Antibiotics Production and Colonization of Wheat Rhizosphere Antagonistic Bacteria against Rhizoctonia cerealis

为明确小麦根围土壤中细菌对小麦纹枯病菌的拮抗作用、拮抗机理及作为生防菌株的应用潜力,对从江苏省姜堰市小麦根围土壤中分离得到的37株假单胞细菌进行了平板拮抗作用测定,获得了10株(T4、T8、T19、T22、T23、Ct10、Ct14、Ct22、Ct26、Ct28)对小麦纹枯病菌禾谷丝核菌拮抗效果明显的菌株。采用传统的生理生化方法,并结合16S rDNA序列分析对这些拮抗细菌进行了鉴定。结果表明,它们都为产荧光假单胞细菌,其中T4、T8、T19、T22、Ct10、Ct22、Ct28、Ct14为Pseudomonas migulae,T23为P.poae,Ct26为P.putida。采用PCR方法检测了这些菌株有关抗生素的产生基因,结果表明,10个菌株都不能产生硝吡咯菌素和藤黄绿脓菌素,菌株T4、T22、T23、Ct26、Ct28可产生2,4-二乙酰基间苯三酚,T4、T8和Ct28可产生吩嗪,T22、T23可产生氢氰酸,除T8、T23、Ct10、Ct26外,其他菌株都不产生几丁质酶;所有菌株都能产生嗜铁素和蛋白酶。在温室条件下研究了这10个菌株对小麦纹枯病的控制作用,结果表明它们都有一定的控病作用,其中菌株Ct26的效果最好,防效达47%。定殖试验结果表明这10个菌株均能在小麦根部定殖,且定殖时间达45 d以上。

Thirty-seven strains of Pseudomonas spp.isolated from wheat rhizosphere in a field of Jiangsu Province,were screened for their antagonistic activity to Rhizoctonia cerealis,the pathogen of wheat sharp eyespot.The bioassay on PDA plates showed that strains T4,T8,T19,T22,T23,Ct10,Ct14,Ct22,Ct26 and Ct28 were significantly antagonistic to R.cerealis compared to other strains.Based on their physiological and biochemical characters and the 16S rDNA sequences analysis,the 10 strains were identified as fluorescent pseudomonads.Strains T4,T8,T19,T22,Ct10,Ct22,Ct28,Ct14 were further identified as Pseudomonas migulae.Strain T23 was P.poae and Ct26 was P.putida.The antibiotics produced by the 10 strains were detected using PCR technology.The results showed that siderophore and proteinase were produced by all of them,while pyrrolnitrin（PRN） and pyoluteorin were absent.Strains T4,T22,T23,Ct26 and Ct28 produced 2,4-diacetylphloroglucinol（2,4-DAPG）.T4,T8 and Ct28 produced phenazine.T22 and T23 produced hydrogen cyanide（HCN）.T8,T23,Ct10 and Ct26 produced chitinase.The biocontrol assay revealed that all of the 10 strains could control the wheat sharp eyespot disease,and among which Ct26 was the best.All of them could colonize in wheat rhizosphere for 45 d or even longer.