Abstract:

The isolation, classification and biological characteristics of the pathogens of Chimonanthus salicifolius leaf diseases were studied. The suspected pathogens of leaf spot disease were isolated from the leaves of sick trees from Shouning County in Fujian Province with in vitro tissue culture method. The fungal pathogens were isolated and classified by colonies, spore morphology identification, and rDNA-ITS and TUB sequence analysis. The biological characteristics and optimal growth conditions of mycelia including temperature, pH value, light, carbon source, nitrogen source, and lethal temperature were explored. Based on the colonies, conidiophore morphology, and rDNA-ITS and TUB sequence alignment, the isolated fungal pathogen was classified into Deuteromycotina, Basidiomycetes, Curvularia, Curvularia intermedia. The studies on the biological characteristics and growth conditions of mycelia indicate that the optimal growth temperature is 30℃, the optimum pH is 8; the best carbon sources are glucose, sucrose and maltose; the most preferred nitrogen sources are potassium nitrate, yeast powder and sodium nitrate; the alternations of light and dark conditions could not affect the growth; and the lethal temperature is 52℃. In summary, the major pathogen of leaf spot disease of Chimonanthus salicifolius from Shouning County in Fujian Province is Curvularia intermedia, which possesses high resistances, strong growth activities, and severe pathogenicity in the environment.

Key words: Chimonanthus salicifolius, pathogen identification, ITS, TUB, biological characteristics