GA1-2菌株的分离鉴定及其对香蕉尖孢镰刀菌的抑菌效果
Isolation, identification of strain GA1-2 and its antifungal activity against Fusarium oxysporum f. sp. Cubense

为了从土壤中分离筛选对香蕉尖孢镰刀菌具有良好拮抗作用的放线菌，采用平板稀释涂布法从四川省会理县干热河谷小麦根际土壤中进行放线菌分离，并采用平板对峙法和孢子萌发法进行筛选，通过形态特征、培养特征、生理生化特征以及16S rDNA序列分析对筛选菌株进行鉴定。结果表明，从四川省会理县干热河谷小麦根际土壤筛选获得一株对香蕉尖孢镰刀菌4号生理小种Fusarium oxysporum f.sp.cubense race 4（FOC4）菌丝和孢子萌发都有很强抑制作用的菌株GA1-2，对FOC4菌丝和孢子萌发抑制率分别为36.34%和94.81%。菌株GA1-2与薰衣草灰链轮丝菌Streptoverticillium lavenduligriseum的亲缘关系最近，相似率达99.85%，且其形态特征、培养特征、生理生化特征也与薰衣草灰链轮丝菌基本相符，因此将菌株GA1-2初步鉴定为薰衣草灰链轮丝菌。
In order to screen antagonistic actinomyce strains with inhibitory activity against Fusarium oxysporum f. sp. cubense race 4 (FOC4) from the wheat rhizosphere soil in dry hot valley of Huili County in Sichuan Province, actinomycetes were isolated with pour plate method and confrontation culture and spore germination method. The results showed that a strain named GA1-2 was isolated by antagonistic experiments against FOC4. The strain GA1-2 had an inhibition rate of 36.34% and 94.81%, respectively, to the mycelial growth and spore germination of FOC4. 16S rDNA sequence analysis exhibited that the strain GA1-2 had the highest sequence similarity with Streptoverticillium lavenduligriseum (99.85%). Reconstruction of a phylogenetic tree revealed that the train GA1-2 had the closest genetic relationship with Stv. lavenduligriseum. Based on the similarity between the strain GA1-2 and Stv. lavenduligriseum in terms of morphological, cultural, physiological and biochemical characteristics and 16S rDNA sequence, the strain GA1-2 was identified as Stv. lavenduligriseum.