Isolation And Molecular Identification Of Colletotrichum Gloeosporioides Causing Brown Spot Disease Of Camellia Oleifera In Hainan Of China

Colletotrichum gloeosporioides is an important pathogen that causes widespread brown spot disease on the leaves of the tea-oil tree (Camellia oleifera) in China. This study was designed to isolate, identify and characterize this fungal pathogen, based on morphology, molecular characteristics and pathogenicity. One pathogenic fungus, named CCG4, was isolated from wild-type Camellia oleifera of Hainan Province. Colonies were regular circular in shape with 50-60mm diameter after 5days of incubation at 28 degrees C on potato dextrose agar (PDA) medium, and woolly with a small amount of jacinth pigment; the colony colour changed from white to black during later stages of infection. The mycelium produced was branched and septate. Conidia were cylindrical-truncate, oblong-obtuse to doliform, colourless with 1-2 hyaline oil globules and 4.5-5.3mx7.7-17.5m. The sporodochia were cushion-shaped. The pathogen was identified as Colletotrichum gloeosporioides on the basis of morphological characteristics and internal transcribed spacer sequence, which showed 100% query cover and 99% similarity to the sequence Colletotrichum gloeosporioides , from a pathogenic fungus known to cause brown spot disease of Camellia oleifera.