Abstract:
Objective Taxonomy of a newly identified pathogen of tobacco plants in Fujian was studied for disease control.
Methods Suspected pathogens were isolated from uncoated tobacco seeds in Fujian and purified using the dilution coating method. Pathogenicity of the isolates was verified by Koch's rule, and taxonomical classification determined by physiochemical assays as well as 16S rDNA, gyrB, and gapA gene sequence analyses.
Results Six morphologically different colonies were shown on culture medium from the seeds of Yunyan 87, Cuibi No.1, and K326 bred in Nanping, Sanming, and Longyan, Fujian, respectively. They appeared 12.50% to 27.50% on the NA medium as moist and yellow with fluorescent pigments colonies and were determined by the Koch's rule being potentially disease-causing microbe. Under a microscope, the Gram-negative bacterium had the shape of short rods. The 16S rDNA, gyrB, and gapA gene sequencing as well as 13 physiological and biochemical tests including oxidase reaction, potassium nitrate reduction reaction, cellobiose and xylose utilizations, and specific primer amplification on the isolate rendered identical results to the control strain LMG 6882 of Burkholderia gladioli.
Conclusion Identified for the first time, B. gladioli isolated from the uncoated seeds of three major tobacco varieties in Fujian could infect the plants by indoor pot inoculation.
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