内蒙古天竺葵腐霉枯萎病病原菌

为了明确天竺葵腐霉枯萎病的病原菌种类,从内蒙古通辽采集天竺葵腐霉枯萎病样品,对病原物进行了分离、纯化和致病性测定,并对病原物进行形态学和rDNA-ITS序列分析鉴定。结果表明,从10个植物样品中分离得到16个腐霉菌株,分别属于终极腐霉Pythium ultimum var. ultimum、瓜果腐霉P. aphanidermatum和两个与P. ultimum var. ultimum相似的待定种。其中,P. ultimum var. ultimum的分离频率为75%、P. aphanidermatum的分离频率为12.5%,两个腐霉待定种的分离频率均为6.25%;P. ultimum var. ultimum是优势类群。致病性测定结果表明,4种腐霉菌都能引起天竺葵腐霉枯萎病,与自然发病症状相同,其中P. ultimum var. ultimum和P. aphanidermatum的致病性较强,发病率分别为71.4%和85.7%。

The pathogen of geranium Pythium blight in Inner Mongolia

The diseased pelargonium hortorum samples infected with Pythium blight were collected from Tongliao City, Inner Mongolia, and totally 16 Pythium isolates were obtained. Based on morphological characteristics and rDNA-ITS sequence analysis, the pathogens were identified as Pythium ultimum var. ultimum, P. aphanidermatum, Pythium sp.¹ and Pythium sp.². P. ultimum var. ultimum was the most dominant (75% of the total isolates), followed by P. aphanidermatum (12.5%) and two other Pythium species (both 6.25%). Pathogenicity tests have proved that the four Pythium species are pathogenic, producing blight symptoms. P. ultimum var. ultimum and P. aphanidermatum are more pathogenic, with infection rate of 71.4% and 85.7% respectively.