山药炭疽病菌拮抗放线菌30702菌株的初步鉴定及发酵培养基优化

Identification and Optimization of Fermentation Medium of Antagonistic Actinomycete 30702 Against Yam Anthracnose

为了寻求一种高效、环保的防治山药炭疽病菌的新方法,采用对峙平板法从热带药用植物根际土壤中筛选到一株对山药炭疽病菌有较好拮抗作用的放线菌30702。经形态特征培养观察和16Sr RNA基因序列分析鉴定为紫黑链霉菌[Streptomyces violaceoniger]16Sr RNA基因进化分枝的放线菌。通过单因子和多因子正交实验对其发酵培养基进行了优化,通过测定菌体湿重和抑菌圈直径,应用SAS9.3软件进行分析,获得最佳发酵培养基为:可溶性淀粉25 g/L、黄豆粉20 g/L、MgSO_4·7H_2O 0.6 g/L、CaCO_30.2 g/L、初始pH为7.0,优化后菌株发酵产物对山药炭疽病菌抑菌活性提高了31.5%。

In order to seek an efficient and environmentally friendly method for the prevention and control of the pathogen of Yam, actinomycetes 30702 with strong antagonistic activity to Yam pathogens was isolated from the rhizosphere soil of medicinal plants and screened by a confrontation method. According to its morphological characteristics and 16 Sr RNA sequence analysis, strain 30702 was identified as a member of Streptomyces violaceusniger 16 Sr RNA gene clade. Through the design of single factor and orthogonal experiment, the fermentation medium for strain 30702 was optimized in shake flask with mycelia quantity and inhibition zone as indicators.The optimal medium was soluble starch 25 g/L, soybean powder 20 g/L, MgSO4·7H2O 0.6 g/L, CaCO3 0.2 g/L, and initial pH is 7. 0. After optimization, the antagonistic activity of strain 30702 against Yam anthracnose increased by 31.5%.