Abstract

                                Rice brown leaf spot disease is one of the most devastating fungal diseases that affect rice plants and reduces the yield across the globe. In the present study, twenty isolates from different rice-growing districts in Tamil Nadu by tissue segment approach was isolated from disease-infected leaves and a purified. The isolates were identified at the genus level using ITS primers, which resulted in an amplicon size of a 550 bp. With the use of species-specific primers of BF and BR the isolate was confirmed as B. oryzae. Gene-specific primers were designed using Primer 3 plus software for the Glycoside hydrolase family 13 protein, which is a highly conserved gene in B. oryzae. All isolates were sequenced using gene-specific primers, and phylogenetic tree analysis was used to investigate the isolate's diversity. The results revealed considerable variance among the B. oryzae collected from different locations of Tamil Nadu with other B .oryzae isolates retrieved from the NCBI database. The isolates were phenotypically validated using morphological and cultural features.

Key words : Brown spot; Bipolaris oryzae; Glycoside hydrolase gene; Molecular characterization