番茄青枯病拮抗菌筛选鉴定及其发酵条件初探

Identification and fermentation of antagonistic bacterium against Ralstonia solanacearum

摘要:

从健康番茄根系采样, 筛选出4 株对番茄青枯病有较强拮抗作用的菌株, 在NA 培养基上抑菌圈直径>9 mm。其中拮抗菌株YB6 抑菌活性最强且拮抗效果稳定, 通过形态学观察及部分生理生化特征测定, 初步确定为节杆菌属。通过单因素试验进行了发酵条件初步研究, 得到适宜的发酵条件为: 发酵时间3 d, 培养温度30 °C, 初始pH 值9.0, 接种量3%, 转速100 r/min, 碳源蔗糖, 氮源酵母浸膏。通过初步优化后拮抗菌株抑菌活性明显增强, 最终对青枯病菌SST-Y 和G2M1.70 抑菌圈直径与NB 培养基相比增加了76.72%和81.14%, 差异显著。

关键词:番茄青枯病, 拮抗菌株, 生理生化, 发酵条件, 抑菌活性

Abstract:

The objective of this study was to screen and identify antagonistic bacteria against Ralstonia solanacearum from tomato rhizosphere soil. Four strains (YB1, YB6, YB22, YB70) showed strong antagonistic activity, with diameters of inhibition zone above 9 mm. The strain YB6, identified as Arthrobacter sp. according to its morphological, physiological and biochemical characteristics, presented the best and most stable effect against R. solanacearum. The fermentation conditions of the strain YB6 were 30 °C, pH 9.0, inoculum 3%, shaking at 100 r/min, sucrose as carbon source, and yeast condensate as nitrogen source. Under the optimized fermentation conditions, diameters of inhibition zone produced by the strain YB6 against R. solanacearum strains SST-Y and G2M1.70 increased by 76.72% and 81.14%, respectively.

Key words:Ralstonia solanacearum, Antagonistic bacteria, Physiological and biochemical characteristics, Fermentation condition, Antibacterial activity