Morpho-physiological characterization of bacterial grain rot in rice seed from Gowa Regency, South Sulawesi

Bacterial Grain Rot caused by Burkholderia glumae is an important disease of rice. In South Sulawesi, this seed-borne pathogen has been detected in several places. There were some reports from the farmers regarding rice yield loss due to this disease. This study aimed to isolate and characterize morpho-physiologically bacterium causing grain rot of rice in the main rice-producing areas of Gowa Regency, South Sulawesi. Samples were obtained from 10 districts. Several grains of rice were isolated and grown in King’s B medium. Morphological characteristics were determined by the color, form, edge, and elevation of colonies. KOH solubility, catalase test, anaerobic growth, toxoflavin production assay, production of fluorescent pigment, and colony color on YDC medium were performed to determine physiological characteristics. 1 isolate from each area was found which has similar morphological traits to B. glumae . Colonies that were yellow, yellowish white, creamy white, and grayish white, with a circular form, entire edge, and convex elevation. The result of physiological characterization showed that all isolates tested positive for KOH solubility and catalase test as well. All isolates showed negative reactions for anaerobic growth, production of fluorescent pigment, and colony color on YDC medium. 5 isolates were able to produce yellow pigment (toxoflavin), so it can be concluded that all of the isolates that have been characterized morpho-physiologically are presumably confirmed as B. glumae .