一种适于分离荔枝霜疫霉的选择性培养基

A selective medium facilitating isolation of litchi downy blight pathogen Peronophythora litchii

为提高荔枝霜疫霉Peronophythora litchii Chen ex Ko et al.的分离成功率,筛选一种适于分离该病原菌的选择性培养基,采用菌丝生长速率法测定了3种杀菌剂和8种抗生素对荔枝霜疫霉及9种常见非目标真菌菌丝生长的抑菌活性。结果表明,以PSA为基础培养基,在其中添加多菌灵、咪鲜胺、异菌脲、利福平和制霉菌素使其浓度分别至10、2、200、10和50μg/m L所配制成的选择性培养基,可有效抑制非目标真菌炭疽菌Colletotrichum sp.、拟茎点霉Phomopsis sp.、链格孢菌Alternaria sp.、镰刀菌Fusarium sp.、拟盘多毛孢Pestalotiopsis sp.、毛霉Mucor sp.、地霉Geotrichum sp.、酵母菌Saccharomyces sp.、裂褶菌Schizophyllum sp.的生长,但对荔枝霜疫霉的生长影响较小。分离实践表明,采用该选择性培养基,不管病组织是否经表面消毒,均可成功分离获得荔枝霜疫霉纯菌落,大大提高了分离的成功率和效率。

In order to improve the isolation rate of the litchi downy blight pathogen Peronophythora litchii Chen ex Ko et al. and develop a selective medium,three fungicides and eight antibiotics were tested to determine their effects on mycelial growth of P. litchii and other nine contaminating fungi. The results showed that the selective medium,which consists of 10 μg a. i. / m L carbendazim,2 μg a. i. / m L prochloraz,200 μg a. i. / m L iprodione,10 μg a. i. / m L rifampicin,and 50 μg a. i. / m L nystatin in potato sucrose agar( PSA) medium,was able to allow P. litchii to grow well and to suppress most of the contaminating fungi, including Colletotrichum sp., Phomopsis sp., Alternaria sp., Fusarium sp.,Pestalotiopsis sp.,Mucor sp.,Geotrichum sp.,Saccharomyces sp. and Schizophyllum sp. The isolation revealed that the pure colony of P. litchii could be successfully obtained,whether the diseased tissues were surface-sterilized or not by using this selective medium. Therefore,the isolation efficiency of P. litchii has been greatly improved.