Morphological and Molecular Identification of Curvularia geniculata Associated with Leaf Spot Disease of Banana in China

The internal transcribed spacer (ITS) region, large subunit ribosomal DNA ( LSU rDNA) , glyceraldehyde-3-phosphate dehydrogenase ( GAPDH), translation elongation factor 1-alpha (TEF-1a) and RNA polymerase II second largest subunit ( RPB2) gene were amplified with primers ITS1/ITS4, LROR/LR5, GPD1/GPD2, EF1-983F/ EF1-2218R and 5F2/7cR, respectively#3 -. Leaf lesions were examined at 7 d post inoculation, and tissues (15 mm2) were selected for fungal re-isolation from the necrotic lesion edges. 3 Results and analysis 3.1 Fungal isolation and morphological observation Fungal colonies appeared and were subcultured after 2 d. Seven days later , subcultures of fungi were grayish geen, and then turned fluffy with grey and white aerial mycelium with age ( Fig. 1 ). Two representative isolates & CATAS-CG01 and CATAS-CG92) were single-spored and stored in the culture collection of the Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences. 3.2Molecular identification and phylogenetic analysis To further confirm the species of the putative pathogen, the ITS region, LSU rDNA, GAPDH, TEF-1a and RPB2 gene of two representative isolates & CATAS-CG01 and CATAS-CG92) were amplified and sequenced with the primers ITS1/ITS4, LROR/LR5, GPD1/GPD2, EF1-983F/EF1-2218R and 5F2/7cR. Pure cultures of C. geniculata were recovered from inoculated leaves, and its taxonomy was confirmed morphologically and molecularly, fulfilling Koch's postulates. 4Discussion C. geniculata has been reported on a wide range of hosts, including banana ' Lacatan ' in Jamaica[11], Discorea spp. in Puerto Rico[12] , Oryza sativa in Indonesia, Trifolium repens, Zingber mioga and Andropogoo furcatus in Japan[10] , Semecarpus kathalekanensis in India[13] , Eleusine indica in China[14] , Microstegium vimineum in China[15] , Paspalum guenoarum in Brazil[16] , Smtcharum officinarum in China[17] and Zea mays in China[18] , which was observed to be associated with leaf spot or blight.