MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF XANTHOMONAS ORYZAE PV. ORYZAE (ISHIYAMA), THE LEAF BLIGHT PATHOGEN OF RICE (ORYZA SATIVA L)
Bacterial blight disease of rice is a serious threat to rice cultivation of India. Xanthomonas oryzae pv. oryzae, (Xoo) theÂ causal organism of bacterial blight disease of rice was isolated from diseased leaf samples and pure cultured on MW medium. TheÂ culture was tested for its pathogenicity on 65 days old seedling of a susceptible rice cultivar Taichung Native-1. With the help ofÂ SES scoring, the cultivar was found to be highly susceptible to the isolate after 30 days of pathogen inoculation. The culture wasÂ microscopically and molecularly identified. Microscopic visualisation of the bacteria through compound microscope at 100XÂ magnification and scanning electron microscope at 9.00K magnification confirmed that bacterial cells appeared in the form of rodÂ shaped measuring each cell size of 1.2 x 0.52 Î¼m. The culture was confirmed as Xoo through molecular identification by using 16SÂ and 23S rDNA gene specific primers. The conserved region of the isolate was amplified and the size was found to be of 470bp inÂ agarose gel electrophoresis The nucleotide sequence obtained was BLAST and was submitted to NCBI. The accession numberÂ obtained for Xoo was MZ158566. Motif analysis of closest species with native Xoo was performed and four conserved sequencesÂ were obtained among the tested strains.