Detection of Xanthomonas oryzae pv. oryzaein rice seeds by molecular techniques

Bacterial blight caused by Xanthomonas oryzae pv. oryzae is one of the most important bacterial diseases on rice and is known to cause heavy economic loss. In the present study, 30 rice seed samples from affected regions were screened for the presence of X. oryzae. pv. oryzae and 20 isolates were identified based on morphological, physiological, biochemical tests and hypersensitive reaction (HR) on tobacco. Molecular detection using a 16S rRNA primer revealed DNA amplification in all 20 isolates, confirmed the pathogen as X. oryzae pv. oryzae.These amplified isolates were further confirmed by using a specific primer synthesized for the hypothetical protein gene. A 331-bp PCR product was obtained in 16 isolates.The application of these molecular tools in the characterization of X. oryzae pv. oryzae is discussed.