甜瓜细菌性斑点病拮抗菌P-13的鉴定及其抑菌物质的初步研究

从新疆甜瓜根际土壤中分离到1株甜瓜细菌性斑点病拮抗放线菌P-13, 根据其形态学、生理特征和16S rRNA序列分析, 鉴定该菌株为娄彻氏链霉菌(Streptomyces rochei)。琼脂扩散法生物活性研究表明, 其发酵液对细菌性果腐病菌(Acidovorax avenae subsp. citrull)BFB、细菌性角斑病菌(Pseudomonas syringae pv. Lachrymans)P4的抑菌圈直径分别为19 mm和17 mm以上; 发酵液中抑菌物质主要为胞外代谢物, 不溶于石油醚, 乙醚, 乙酸乙酯等有机溶剂。在100°C处理10 min、pH 6处理6 h或紫外线照射7 h, 该物质抑菌活性不变。纸层析结果表明, 该物质主要为碱性水溶性物质。

Identification of Antagonistic Strain P-13 and the Preliminary Studies on Its Antimicrobial Substances Against Bacterial Spot Diseases of Muskmelon

An actinomycete strain P-13, with antimicrobial activity against muskmelon bacterial spot pathogens, was isolated from the muskmelon rhizosphere soil samples in Xinjiang. The strain P-13 was identified as Streptomyces rochei based on morphological, physiological characteristics and 16S rRNA sequence analysis. The agar diffusion bioassay showed that the diameter of inhibition zone against Acidovorax avenae subsp. citrull BFB and Pseudomonas syringae pv. Lachrymans P4 was above 19 mm and 17 mm, respectively. The antimicrobial substances obtained from strain P-13 were demonstrated to be alkaline and water-soluble compounds according to paper chromatogram analysis and exocellular metabolites. Furthermore, it was stable to be treated by 100°C for 10 min, pH 6 for 6 h, or ultraviolet treatment for 7 h. Moreover, it was insoluble in organic solvents, such as petroleum benzine, diethyl ether, and acetic ether.