摘要： 以患轮纹病的冬枣果肉组织作为分离对象,将筛选出的真菌经单孢分离纯化后进行回接试验。依据回接试验中接菌枣果的发病症状确定出冬枣轮纹病的病原真菌,并通过其形态特征、培养特性及ITS序列分析对该菌株进行鉴定。摸索该病原菌的最适培养条件,同时测定了该病原菌的胞内毒素及胞外毒素的毒力。利用平板对峙培养法筛选有拮抗作用的细菌,并进行该拮抗细菌的形态特征观察、生理生化试验及16S rDNA序列分析。结果表明:本研究中分离的致冬枣轮纹病病原真菌为Botryosphaeria dothidea,该菌最适碳源为蔗糖,最适氮源为蛋白胨,最适pH值为5,最适生长温度为27℃。筛选获得对该致病真菌有一定拮抗作用的细菌JK,初步鉴定为芽孢杆菌属(Bacillus sp.)。即本研究中筛选的芽孢杆菌属(Bacillus sp.)细菌在冬枣轮纹病的生物防治方面有潜在的应用价值。

关键词: 冬枣, 轮纹病, 病原真菌, 毒力, 拮抗细菌

Abstract: The pathogenic fungus of ring grain disease of Winter Jujubes was isolated,screened and identified, and its antagonistic bacterium was determined. Taking the fruits infected by ring grain disease of Winter Jujubes as the target,the pathogenic fungus of ring grain disease was confirmed by reinoculating test. The pathogenic fungus was identified by the morphological characteristics and ITS sequence analysis. Moreover,culturing characteristics, intracellular toxin and extracellular toxin was studied. The antagonistic bacterium was screened using the confront antibiotic culture experiment,and it was identified using the morphological,physiological and biochemical characteristics combined with 16S rDNA gene sequence analysis. The pathogenic fungus was successfully screened from the fruits infected by ring grain disease. Based on its morphology,cultural characteristics as well as ITS sequence analysis,the pathogenic fungus was identified as Botryosphaeria dothidea. The single factor experiments show that the optimal carbon sources,nitrogen sources,pH,growth temperature were sucrose,peptone,5,27 ℃,respectively. One bacterium isolated from the local soil showed strong antagonistic activity against the pathogenic fungus of ring grain disease,and it was identified as Bacillus sp.. The strain of Bacillus sp. has a potential application in the biological control to the ring grain disease of Winter Jujubes.

Key words: Winter Jujubes, Rind gain disease, Pathogenic fungus, Toxicity, Antagonistic bacterium

中图分类号: 

• S432.4