北京市月季丽赤壳褐斑病病原菌鉴定

Identification of pathogen causing Calonectria leaf spot on Rosa chinensis in Beijing

In September 2018, a new leaf spot on Rosa chinensis with incidence of up to 60% was observed in a park in Miyun district of Beijing. Disease samples were collected and three strains (JZB3210001, JZB3210002 and JZB3210003) were obtained by isolation and single spore purification. According to the morphological characteristics, they were identified as Calonectria sp.. For molecular phylogenetic analysis, β-tub, Cal, H3, EF1-α genes were amplified with genomic DNA of these three isolates. Phylogenetic trees constructed by the Maximum likelihood method showed that three strains clustered with Calonectria blephiliae CBS136425 as a distinct clade with 91% bootstrap support. Based on both morphological characteristics and phylogenetic analysis, the three strains were identified as C. blephiliae. The pathogenicity assay confirmed that C. blephiliae was the pathogen causing this disease. This is the first report of leaf spot caused by C. blephiliae on Rosa chinensis in China.