致病疫霉拮抗放线菌的筛选及抑菌作用初步研究

Screening of antagonistic actinomycetic strains and their inhibitions against Phytophthora infestans

为获得对致病疫霉具有显著且稳定拮抗作用的放线菌,利用对峙培养法和滤纸片法测定了从土壤中分离纯化出的放线菌活体及其发酵液对致病疫霉生长的抑制作用,并对其中抑菌效果显著的Sy11菌株的抑菌方式、对致病疫霉的感应性、传代稳定性以及对致病疫霉菌体形态的影响进行了初步研究。结果表明,分离纯化出的74株放线菌中有17株对致病疫霉具有拮抗作用,但其发酵液对致病疫霉均无抑制作用;Sy11菌株只有感应到致病疫霉存在时才分泌对致病疫霉的抑菌物质;连续传代25次后,Sy11菌株的抑制率仍然保持在81%以上;Sy11菌株可导致致病疫霉菌丝体严重变形,但只是抑制其生长,并未杀死致病疫霉。这些结果表明,Sy11菌株在防治马铃薯晚疫病方面具有较大的应用潜力。

In order to obtain highly effective and stably antagonistic actinomycetes strains against Phytophthora infestans, the inhibitory effects of living and fermentation filtrates of actinomycetic strains isolated from vegetable-grown soil on mycelial growth of P. infestans were detected with dual-culture and filter paper methods, and inhibitory manner, response to P. infestans, stability of inhibition effect after continuous passage culture, and influence on P. infestans mycelial morphological character were investigated in this experiment. The results showed that 17 of 74 strains were evidently antagonistic to P. infestans, but all of fermentation liquors of 17 strains were not antagonistic to P. infestans. Syll strain had response to P. infestans, and could produce and secrete some substances inhibiting P. infestans. After continuous passage culture for 25 times, the inhibitory rate of Syll strain on P. infestans still maintained over 81%. Syll strain could cause to lose original sketch and structure seriously. However, Syll strain just inhibited P. infestans but did not kill it. These results indicated that Syll strain might have a great potential in control potato late blight in future.