Etiology of Chinaberry Gall Disease in Iran

Chinaberry (Melia azedarach L.) is a beautiful tree indigenous to the Himalayas that grows as a native plant in Iran. Symptoms similar to bacterial gall have been observed on the crown, shoot and twig of chinaberry, a recent landscape tree since 2003-2004 in Shiraz, Fars province, south of Iran. A gram negative bacterium was isolated from the galls. The isolates did not produce fluorescent pigment on King's B medium, were negative in oxidase, levan production, potato soft rot, casein, gelatin hydrolysis, nitrate reduction, growth at 5oC, uease production and indol production, but were positive in arginine dihydrolase, catalase, growth at 35oC, and also produced hypersensitive reaction on tobacco. Wound inoculated bacterial suspension into chinaberry seedlings produced galls from which the bacterium was reisolated. Systemic movement of the isolates into the vascular system of chinaberry was shown by the formation of gall above the inoculation site on the stem. On the basis of biochemical, physiological and pathogenicity characteristics, the isolated bacteria were identified as Pseudomonas meliae. Electrophoretic pattern of cell proteins showed that chinaberry isolates were different from P. syringae, P. viridiflava, P. fluorescens, P. savastanoi. The current article is the first report of bacterial gall disease of chinaberry in Iran.