Molecular Methods For Detection Of Burkholderia Glumae And Identification Of The Casual Organism Of Bacterial Brown Stripe Of Rice

Burkholderia glumae induced grain rot and seedling rot symptom of rice is threatening to rice production in the distributed countries. Because of the quarantine importance, it was listed as a quarantine pest in 2007 by Chinese Ministry of Agriculture, however, little information is available for the detection of the pathogen in China. The present study combined the Real-time PCR method with classical PCR to increase the detecting efficiency, and to develop an accurate, rapid and sensitive method to detect the pathogen in plant quarantine for effective management of the disease. The results showed that all the strains of B. glumae tested produced about 139bp specific fragments by the Real-time PCR and the general PCR method, while others showed negative PCR result. Comparing the sensitivity of these two detecting methods, about 10~4CFU/ml of the bacterial suspension were detected by general PCR and 10~2CFU/ml can be detected by Real-time PCR method. B. glumae can be detected when the healthy seeds and inoculated seeds mixed with a proportion of 1:100.Bacterial brown stripe of rice can be caused by two different pathogens: Acidovorax avenae subspecies avenae and Pseudomonas syringae pv. panic. They induce rice seedling rot which is one of the major seedling diseases of rice. For determining the pathogen from brown stripe of rice seedling and controlling it effectively, 4 out of 6 bacterial strains isolated from the diseased rice seedlings were compared with 3 standard reference strains of Acidovorax avenae subsp. avenae and 2 standard reference strains of Acidovorax avenae subsp. citrulli by the bacteriological tests, colony morphology, pathogenicity, Biolog, FAME analysis, electromicroscope observation and nested-PCR. It has been confirmed that Acidovorax avenae subsp. avenae is the causal agent of bacterial brown stripe of rice in this study. The results also showed that FAME analysis misidentified some strains of Acidovorax avenae subsp. avenae as A. avenae subsp. citrulli while Biolog and the nested-PCR were the best way for differentiating the 2 bacterial pathogens.