烟草病原真菌研究中的一种选择分离技术

Study on a Selective Isolation Method for Fungal Pathogens of Tobacco

用含利福平(400微克/毫升)的马铃薯琼脂培养基(R-PDA)分离5种病原真菌,检出率可达63.8％,无细菌污染,非目标病原的真菌污染率减少34％。对照(PDA)的病原检出率是25％,细菌污染率为89.4％。使用利福平选择分离技术还可简化分离程序,单消毒(70％酒精)较二次消毒(酒精—升汞)的病原检出率高77.2％。同时,利用利福平作为选择分离中的杂菌抑制剂,不影响病菌的生物学性状和致病力。烟草及其它作物的真菌性病害,尤其是根茎病害的病原分离常受细菌污染。而且由于许多细菌存在于植物组织内,表面消毒并不能把它们杀死;而消毒剂内渗又往往会杀死分离的目标病原物。因此,如何防止细菌的污染并获得高的病原检出率,对真菌性病害样本的分离是一个限制性问题。本文报道一项可以解决这一问题的选择分离技术。

The R-PDA medium was made by adding 400ug/ml rifimpicin to common PDA medium and used for isolating 5 species of tobacco pathogenic fungi. With R-PDA studying, the 63. 8% of detected frequency of different pathogens was obtained with no contamination by bacteria and as less as 7.5% contamination by nonpathogenic fungi. While the PDA medium as a control gave only 25% detected frequency for pathogens with 89. 4% contamination by bacteria. This selective isolation method could make the isolating procedures simple. Only sterilization by 70% alchol without using mercuric chloride gave the detected frequency for pathogens 74. 2% higher than double sterilization of alchol followed by mercuric chloride. Furthermore, no effects on the pathogenicity of the pathogen were brought about by the application of ricimpicin in R—PDA medium.