两种配方快速分离纯化马铃薯致病疫霉菌株效果的比较

Comparison of Isolation Efficiency of Phytophthora infestans with Two Antibiotics Formulas

为了能在田间快速分离马铃薯致病疫霉菌株,同时能将实验室内被污染的致病疫霉菌株有效地纯化出来,对在黑麦培养基中添加制霉菌素配方和红药水配方分离致病疫霉菌株的效果进行了比较。结果显示,从田间马铃薯病叶上直接分离致病疫霉菌株时,制霉菌素配方的纯化率高于红药水配方,分别为74%和52%;在分离实验室受杂菌污染的致病疫霉菌株时,红药水配方的纯化率高于制霉菌素配方,分别为78%和36%;两种配方对致病疫霉菌株后期生长均有一定的抑制作用,其中制霉菌素配方的抑制作用明显强于红药水配方,两者的生长抑制率分别为65.79%和18.63%;然而,两种配方对致病疫霉菌株后期产生孢子囊的数量、孢子囊直接萌发和游动孢子释放、致病疫霉菌丝体的可溶性蛋白含量都没有显著影响,同时在3个感病马铃薯品种上的致病性也均没有明显影响。田间病叶上采集的致病疫霉菌株在制霉菌素配方的黑麦培养基冻存管中20℃最长可保存16个月,表明制霉菌素配方更适合于田间快速分离纯化致病疫霉菌株,而红药水配方更适合于分离纯化实验室内被污染的致病疫霉菌株。

The isolation ofPhytophthora infestans strains from diseased leaves of potato in field and from the media of contaminating microorganism in lab is difficult with traditional method. The purpose of this experiment is to compare the isolation efficiency of P infestans by Nystatin formula and Merbromin formula in rye culture medium. The results showed that purification rates of Nystatin formula and Merbromin formula was 74% and 52% from diseased potato leaves in field, respectively, but that were 36% and 78% from the media of contaminating microorganism in lab, respectively. The two formulas had some inhibition on mycelia growth of P. infestans and Merbromin formula displayed stronger inhibition in comparison with Nystatin formula, the inhibition rates were 65.79% and 18.63%, respectively. However, the two formulations had no significant effect on spoangia formation, sporangia direct germination, and zoospores release, as well as the mycelia protein content of Pinfestans. In addition, both Nystatin formula and Merbromin formula did not affect the pathogenicity ofP. infestans on potato tuber slices of tested three varieties. The strains isolated from diseased potato leaves in field could be kept for 16 months in frozen storage tube of rye culture medium adding Nystatin formula. These findings indicate that Nystatin formula is suitable for isolation of P. infestans strains from field and Merbromin formula for that from lab.