放线菌NF0919的鉴定及生防活性

为研发新的防治作物病害的生防药剂，用平板对峙培养法测定放线菌NF0919(分离自牛粪微生物群落)抑菌谱，并通过菌株形态学观察、培养特征、生理生化特性和分子分类法研究其分类地位，同时对其发酵产物粗提物(CE)进行室内毒力测定和田间防效试验。结果表明，放线菌NF0919对供试植物病原真菌均有不同程度的抑制作用，其中对葡萄炭疽病菌(Glomerella cingulata)、草莓炭疽病菌(Glomerella fragariae)、油菜菌核病菌(Sclerotinia sclerotiorum)、水稻纹枯病菌(Thanatephorus cucumeris)和苹果轮纹病菌(Botryosphaeria dothidea)的抑制作用较强，其抑菌圈半径均大于15 mm；CE对葡萄病原真菌的室内毒力和田间防治效果都显著优于化学对照药剂(多菌灵)；根据菌株形态观察、生理生化特征和16S rRNA基因序列比对分析，初步鉴定该菌株为黄色链霉菌(Streptomyces corchorusii)。

Biocontrol Activity and Taxonomy of Actinomyces Strain NF0919

To discover new biological control agents,the biocontrol activity of actinomyces strain NF0919 screened from cowdung microflora was interpreted by dual cultural plate method,indoor toxicity and field effect test of crude extracted of fermentation (CE). Based on the morphological,chemical and molecular taxonomy methods,the strain NF0919 was identified. Results revealed that the strain NF0919 displayed a broad spectrum inhibitive activity,and the width of inhibitive zones against Glomerella cingulata,Glomerella fragariae,Sclerotinia sclerotiorum,Thanatephorus cucumeris and Botryosphaeria dothidea was greater than 15 mm. Data of indoor toxicity and field experiments of CE demonstrated that the field biocontrol efficacy and the effective concentration for 50% inhibition of pathogens mycelial growth (EC₅₀) was all superior to the chemical control (Carbendazim). According to the morphological,cultural,physiological and biochemical characteristics,and 16S RNA gene sequence,the strain NF0919 was identified as Streptomyces corchorusii.