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目的:鉴定益母草斑枯病的病原,为该病害的深入研究和防治提供科学依据。方法:通过常规植物病理学组织分离方法对病原菌进行分离;室内人工接种进行致病性测定;利用病原菌的r DNA ITS序列构建系统发育树来确定病原菌的分类地位。结果:该菌分生孢子器球形或扁球形,直径(86~165)μm×(80~130)μm;具孔口,分生孢子针形,3~14个隔膜,大小(48~90)μm×(1.4~1.8)μm。在PDA培养基上,菌落黑灰色,生长速度为1.33mm/d,大量的分生孢子器半埋生在培养基中,分生孢子两端和中间细胞均可萌发长出无色芽管。通过r DNA ITS序列构建系统发育树,该菌与野芝麻壳针孢Septoria lamiicola Passerini聚为一类。结论:依据形态学和r DNA ITS序列分析结果,确定引起甘肃省益母草斑枯病的病原为野芝麻壳针孢Septoria lamiicola Passerini。
Objective: To identify the pathogen of Motherwort spot blight and provide a scientific basis for the further study and prevention of the disease. Methods: The pathogen was isolated by routine plant pathology tissue isolation method. Pathogenicity was determined by artificial inoculation in laboratory. The phylogenetic tree was constructed by using rDNA ITS sequences of pathogenic bacteria to determine the taxonomic status of pathogens. Results: The conidia of this strain were spherical or oblate, with diameters of (86-165) μm × (80-130 μm), with orifices and conidiophores, 3-14 septums, μm × (1.4 to 1.8) μm. On the PDA medium, the colony is dark gray with a growth rate of 1.33 mm / d. A large number of conidiophores are partially buried in the medium, and both ends of the conidia and the middle cells can grow colorless colloidal germs. The phylogenetic tree was constructed by r DNA ITS sequence, which was clustered with Septoria lamiicola Passerini. Conclusion: Based on the morphological and rDNA ITS sequence analysis results, the pathogen of spot blight caused by Motherwort in Gansu Province was identified as Septoria lamiicola Passerini.