土壤拮抗放线菌的分离及其抗菌活性筛选

以常见植物病原真菌和细菌为指示菌,从分离的422株放线菌中筛选出28株可代谢抗细菌活性物质的菌株,其中N331、N393菌株发酵液对供试12种真菌有显著的抑制作用。离体条件下,N331、N393菌株发酵液对供试真菌菌丝生长的抑制中浓度(EC50)均小于15 mL/L;对玉米弯孢病菌、棉花枯萎病菌、小麦根腐病菌、黄瓜霜霉病菌孢子萌发的EC₅₀亦小于15 mL/L。盆栽试验结果表明,N331、N393菌株发酵原液对黄瓜霜霉病的保护效果分别为97.4%和85.6%,治疗效果分别为83.3%和59.3%。

Isolation and screening of antagonistic actinomycetes from soils

The antimicrobial activity of the actinomycetes isolated from soils was tested against plant pathogenic fungi and bacteria.The results of in vitro bioassays demonstrated that the fermentation broths of the 28 strains tested showed remarkable inhibitory activities against the bacteria examined.Meanwhile,only the fermentation broth of strain N331 and N393 exhibited inhibitory activity against plant pathogenic fungi by affecting mycelial growth rate,and the EC₅₀ values were less than 15 mL/L.Furthermore,the fermentation broth of these 2 strains also inhibited the spore germination of Curvulavia lunata,Fusarium oxysporum,Bipolaris sorokiniana and Pseudoperonospora cubensis,with EC₅₀ values less than 15 mL/L.The protective efficacy of the fermentation broths originated from strains N331 and N393 was 97.4% and 85.6%,and the curative efficacy were 83.3% and 59.3% in pot tests against Pseudoperonospora cubensis,respectively.