Effect of Chitinase-Producing Strain V-8 on Controlling Cotton Fusarium Wilt

一株几丁质酶产生菌V-8对棉花枯萎病的防治作用(英文)

[Objective] This study aimed to screen endophytic bacteria which is antag- onistic to cotton Fusarium wilt. [Method] Fresh cotton plants collected from cotton- growing areas in Jingzhou City, Hubei Province were used as experimental materials to isolate endophytic bacteria. Through chitinase test and co-culturing both micro-or- ganisms side by side on the same PDA culture plate, antagonistic strains to cotton Fusarium wilt were screened. [Result] A total of 83 bacterial isolates were obtained from cotton plants grown in the fields, six of which were chitinase-productive bacte- ria. Through chitinase test and co-culturing both micro-organisms side by side on the same PDA culture plate, strain V-8 which had the strongest antagonistic effect on Fusarium oxysporum f. sp. vasinfectum was screened. Strain V-8 had a wider anti- fungal spectrum with certain inhibitory effect on all the six important pathogenic fungi including Fusarium oxysporum f. sp niveum; it colonized stably in the rhizospheric soil of cotton, with a colonization density of up to 6.2x10s cfu/g fifty days after inoc- ulation; the relative effect on controlling cotton Fusarium wilt in pot test was 73.2%. The Findings of this study suggested that strain V-8 had great potential for biological control of cotton Fusarium wilt and could be taken as a substantial material for the cloning of chitinase genes. [Conclusion] The results from this study provides bases for the control of cotton fusarium wilt, as well as the exploitation of endophytic bac- teria resources in cotton and the development of novel biological pesticides.

[目的]筛选对棉花枯萎病菌有拮抗作用的内生菌株。[方法]以采自湖北荆州棉花种植区的新鲜棉花植株为试验材料,对其进行内生菌株的分离,再通过几丁质酶及平板对峙双重筛选对棉花枯萎病菌有拮抗作用的菌株。[结果]从大田棉花植株内分离出83株细菌,其中6株为几丁质酶产生菌。通过几丁质酶及平板对峙双重筛选,从中获得菌株V-8对棉花枯萎病菌(Fusarium oxysporum f.sp.vasinfectum)拮抗作用最强,该菌株具有较宽的抑菌谱,对西瓜枯萎病菌(Fusarium oxysporum f.sp niveum)等6种重要病原真菌均具有一定的抑制作用;在棉花根际土壤能稳定定殖,50d后定殖密度达6.2×105cfu/g;对棉花枯萎病的盆栽防效为73.2%。表明内生细菌V-8对棉花枯萎病的生物防治具有较大的潜力,可作为几丁质酶基因克隆的重要材料。[结论]该研究结果为棉花枯萎病的防治以及充分开发棉花内生菌资源、研制新型生物农药奠定了基础。