中文摘要：

从紫花苜蓿中分离出一株内生菌Y23,评价其对尖孢镰刀菌（Fusarium oxysporum）的抑制作用。经过16S r DNA序列分析,结合菌落形态,鉴定Y23属于不动杆菌。在平板对峙实验中,该菌株对尖孢镰刀菌有抑制作用,其抑菌率为27.70%。该菌株发酵液对尖孢镰刀菌菌丝及孢子的生长也有抑制作用,可以使尖孢镰刀菌菌丝和孢子的数量明显减少,菌丝体断裂、扭曲,菌丝顶端膨大。对该菌株嗜铁素合成量进行检测,其值为0.725。结果表明,该菌株对尖孢镰刀菌有一定的抑制效果。

英文摘要：

One endophytic bacterial strain Y23 was isolated from leaves of Medicago sativa, and tested the inhibition of Fusarium oxysporum. Y23 was identified as Acinetobacter on the basis of 16 S r DNA sequence analysis and the colony morphology. In dual culture assay,the strain had an inhibitory effect on Fusarium oxysporum and the inhibitory rate was 27.70%. The fermentation broth of the strain also had an inhibitory effect on the growth of mycelia and spores of F. oxysporum. It could make the number of mycelia and spores of F. oxysporum decreased obviously, the mycelia broken and twisty, and the end of the mycelia intumescent. The synthesis of siderophore of the strain was tested and the value was 0.725. All the results indicated that the strain had a certain level of inhibitory effect on Fusarium oxysporum.