放线菌Ⅲ-61和A-21对蔬菜枯萎病和灰霉病的控制作用

Control Effect of the Actinomyces Strains Ⅲ-61 and A-21 to Fusarium Wilt and Gray Mold of Vegetables

为了明确拮抗性放线菌Ⅲ-61和 A-21在植物病害生物防治中的实用价值,并为其后续的生防制剂的研发提供科学依据,对其在蔬菜枯萎病和灰霉病上的抗病活性进行了研究.其活菌体的抑菌活性检测采用平板对峙法;菌体代谢物的活性测定利用摇瓶发酵后经微孔滤膜过滤制备无菌发酵液,然后用滤纸片扩散法测定抑菌圈,用生长速率法测定对菌落扩展的抑制,用稀释药液凹玻片静置培养法测定对孢子萌发的抑制;温室防病试验采用盆栽接种法.结果显示,两菌株的平板菌落对黄瓜枯萎病菌和番茄灰霉病菌的抑菌带宽达17.5～20.9 mm;27 ℃,120 r/min摇瓶培养6 d的发酵液抑菌效果最好,其稀释倍数≤5的无菌滤液处理后经120 h对病原菌菌丝生长的抑制率仍达76.5%～100%,对分生孢子萌发的抑制率为100%;100倍稀释液对孢子萌发后的芽管具有致畸作用,使其顶端膨大或呈粗栉齿状而不再继续伸长;平板对峙培养中受抑病原菌菌落边缘的菌丝细胞壁崩解,原生质体外泄,表现出溶菌现象;其4倍稀释液对黄瓜枯萎病的温室盆栽防效分别为 65.15%和60.61%,对番茄和辣椒灰霉病的防效为62.49%～89.76%.此研究结果表明这2个菌株具有很好的开发应用前景.

A study on the biocontrol efficacy of the actinomyces strains Ⅲ-61 and A-21 against fusarium wilt and gray mold of vegetables was launched for the sake of evaluating the application significance of the two strains for the biological control of plant diseases, and providing scientific basis for the follow up research on their development. In which, the antifungal bands of 17.5 - 20.9 mm wide produced by living colonies of the two strains against ones of Fusarium oxysporum f. sp. cucumerinum and Botrytis cinerea were obtained by using the method of culturing colonies confronting each other on plate. The suppressing rates of 76.5 % - 100 % to the growth of pathogen mycelia with the method of growth rate, the inhibiting rate of 100% to the conidial germination of pathogens with the method of germinating on concave sheet glasses were presented by their germfree ferment filtrate diluted by 5 times, and the distorting rate of 100% to germ tubes of the conidia by the filtrate diluted by 100 times were also observed . The fungilytic action to hyphae of the pathogens on plates was presented by the two strains too. In greenhouse potting trial with the ferment solutions diluted by 4 times, the relative control efficiencies to cucumber fusarium wilt were 60.61% - 65.15% ,to gray molds of tomato and pepper were up to 62.49 % - 89.76 %. The result showed that the two strains are excellent biocontrol materials with good prospects of development and application.