Identification of the pathogen of asparagus stem blight and analysis of its regional difference
Asparagus stem blight is a regional devastating disease. To identify accurately the pathogen and to resolve any differences in isolates from different provinces, morphological examination and genotyping of rDNA ITA sequences following a GenBank BLAST search sequences, the differences in both biological characteristics and ITS sequences were compared, and the phylogenetic relationship was analyzed. The results revealed that the identity of the asparagus stem blight fungus was Phomopsis asparagi. The growth rates isolates from Hainan were the fastest, with an average diameter of 8.5 cm after 5 days' culture. After 14 days' culture, the colony of isolates from Jiangxi grew pale green from white, those from the other provinces grew gray white from white, and that from Hainan displayed concentric wheel pattern. The number of pycnidia of isolates from Fujian was the highest with an average count of 60 dish‑1. There existed differences in in the 1-238 bp and 298-591 bp fragments of ITS sequences in isolates from five provinces, of which more differential bases appeared in the isolates from Hebei. Isolates from the five provinces clustered into two groups, of which the isolates from Hebei clustered a single group and the ones from the other provinces clustered another group, fungi from the same genus clustered together, and P. asparagi behaved nearer in phylogenetic relationship with P. phyllanthicola.
Yang, Ying-Qing, Sun, Qiang, Li, Chuan-Ming, Chen, Hong-Fan, Zhao, Feng, Huang, Jian-Hua, Li, Xiang-Min and Lan, Bo (2020). Identification of the pathogen of asparagus stem blight and analysis of its regional difference. Acta Hortic. 1301, 185-192
asparagus, stem blight fungus, identification, rDNA ITS, phylogenetic relationship, regional difference