番茄内生菌St24的鉴定及其对灰霉病的生防作用

从番茄植株根茎部分离到1株有抑菌活性的植物内生放线菌菌株St24，对其分类地位以及对灰霉病菌的防治效果进行研究.结果表明: 菌株St24为酒红链霉菌.St24发酵液经石油醚萃取得到的粗提物对多种病原菌有抑制作用，其中对灰霉病菌的抑制作用最强，抑制菌丝生长的EC₅₀为11.78 mg·L^-1.粗提物处理灰霉菌后，菌丝量减少，菌丝体皱缩、断裂、原生质外渗，菌体细胞表面有许多瘤状畸形.处理后的灰霉病菌培养液在260 nm处比对照多出现一吸收峰，说明粗提物对病原菌的细胞膜透性有影响.经盆栽试验, St24发酵液对番茄灰霉病有保护和治疗的作用，100 mg·L^-1粗提物叶面喷雾的保护作用效果最好，24 h后防效达到94.3%，120 h后为85.4%.

Identification of endophytic actinomycete St24 tomato plants from and its application in bio-control of gray mold disease

An endophytic actinomycete strain St24 with acaricidal activity was isolated from the root-stem junction of tomato plants,with the taxonomic position of the strain and its control effect against gray mold disease investigated.The St24 was identified as Streptomyces vinaceus,and its broth’s petroleum ether extracts could inhibit a variety of pathogens.The inhibitory effect of the extracts on Botrytis cinerea was the strongest,with the EC50 of inhibiting B.cinerea mycelia growth being 11.78 mg·L-1.After treated with the extracts,the amount of the mycelia decreased,and the mycelia became crenate or broken,with the protoplast extravasated and the tuberculate malformation appeared.The B.cinerea culture treated with the extracts showed the maximum absorption at 260 nm,which was absent in the control,indicating that the St24 extracts increased the pathogens cell membrane permeability.Pot experiment showed that the extracts could protect tomato plants against B.cinerea.Foliar spraying the extracts at 100 mg·L-1 had the best protective effect,with the controlling effect reached 94.3% after 24 h and 85.4% after 120h.