胶孢炭疽菌生防放线菌SD-29的鉴定及抗菌活性评价

Identification and antifungal activity of a biocontrol actinomycete strain SD-29 against Colletotrichum gloeosporioides

摘要:

【背景】胶孢炭疽菌是引起橡胶炭疽病的一种重要病原菌，可导致橡胶树产胶量下降。【目的】从山东青岛一农田土壤中分离出一株胶孢炭疽菌生防放线菌SD-29，并对其进行鉴定及抗菌活性评价。【方法】采用对峙生长法及菌丝生长速率法对菌株SD-29的拮抗活性进行鉴定；利用乙酸乙酯萃取法提取菌株SD-29发酵液粗提物并进行活性评价；根据菌株SD-29的形态特征、生理生化及16S rRNA基因序列进行鉴定。【结果】菌株SD-29对胶孢炭疽菌具有较强的抑制活性，皿内抑制活性达到82.6%。发酵液粗提物对菌丝生长的EC50为13.6 μg/mL，100 μg/mL的粗提物对胶孢炭疽菌孢子萌发抑制率达到63.16%，其对感炭疽病橡胶叶片的防治效果达到48.96%。根据该菌的形态特征、生理生化特征及16S rRNA基因序列分析鉴定菌株SD-29为streptomyces yatensis。【结论】菌株SD-29对胶孢炭疽菌有较强的防治效果，具有潜在的应用价值。

Abstract:

[Background] Colletotrichum gloeosporioides can infect rubber tree, and decrease rubber production. [Objective] An antagonistic strain SD-29 against C. gloeosporioides was isolated from farmland soil in Qingdao, Shandong province. The strain was identified, and its antifungal activity was evaluated. [Methods] The antifungal activity of strain SD-29 was determined using the methods of confrontation growth and mycelium growth rate. The crude extract of the fermentation broth was obtained by ethyl acetate extraction, and its activity was also evaluated. Then, strain SD-29 was identified based on morphology, physiological, biochemical characteristics and 16S rRNA sequence. [Results] Strain SD-29 had a strong inhibitory activity to C. gloeosporioides with the inhibition rate of 82.6%. The EC50 of fermentation broth extractions was 13.6 μg/mL. Crude extract (100 μg/mL) inhibited conidial germination with the inhibition rate of 63.16%, and its control effect on the rubber leaves infected with C. gloeosporioides was up to 48.96%. According to the results of morphology, physiological, biochemical characteristics and 16S rRNA sequence, strain SD-29 was identified as Streptomyces yatensis. [Conclusion] Strain SD-29 has a strong control effect on C. gloeosporioides.