新疆棉花立枯病根际拮抗细菌的筛选

为棉花立枯病生物防治提供新的生防细菌菌株,从采集的48份新疆棉苗根际土样中经分离、纯化获得优势细菌菌株189个,采用平板对峙培养法对立枯丝核菌(Rhizoctonia solani)进行根际拮抗细菌的筛选,并对部分抑菌活性强菌株的抑菌作用进行研究。结果表明,共获得根际拮抗细菌菌株67株;其中菌株MX-1抑菌谱广,抑菌活性强,具有几丁质酶活,其盆栽试验防治效果达59.8%;饱和度70%硫酸铵获得的抑菌物质热稳定性较好,抑菌活性最高,能够引起立枯丝核菌菌丝发生畸变,出现囊泡、甚而裂解。由此可知,菌株MX-1是一株具有良好应用潜力的防治棉花立枯病的生防菌。

Screening of antagonistic rhizobacteria against Rhizoctonia solani-induced damping-off of cotton in Xinjiang

The aim of this paper was to screen the new antagonistic bacteria against Rhizoctonia solani.Totally 189 strains were isolated from 48 soil samples collected from Xinjiang cotton rhizosphere,and the antifungal effect of some strains were tested in plate assay.Results showed 67 antagonistic rhizobacteria were obtained,among which strain MX-1 with chitinase activity exhibited a broad-spectrum antifungal activity towards several cotton phytopathogenic fungi,and reduced cotton damping-off incidence by 59.8% under growth room conditions.The antifungal metabolite by strain MX-1 precipitated by 70% ammonium sulphate was stable to heat treatment,and showed the most effective inhibition toward R.solani such as distortion,swelling,ultimately lysis of hyphae.These results suggest strain MX-1 can be used as potential biological control agent to deal with cotton damping-off disease in Xinjiang.