First report of bacterial black spot of mango in Iran.
Najafipour G., Boroumand M., Ayazpour K.
Author Affiliation: Department of plant protection, Jahrom Branch, Islamic Azad University, Jahrom, Iran.
Indian Journal of Fundamental and Applied Life Sciences 4 : 190-196
Abstract : During 2012, mango's orchards in different regions of Hormozgan province of Iran were evaluated. Plants with bacterial black spot symptoms were collected and transferred to the laboratory. Samples were washed with running water for 3 minutes, split to small pieces in sterile distilled water and were maintained in the laboratory condition for an hour. The resulting suspension was cultured in NA medium and incubated at 28°C. Colonies that appeared at 2-5 days were purified and tested. All isolates were gram negative, obligate aerobic and were able to grow on SPA medium. Strains were positive in hypersensitive reaction on geranium, catalase, levan production, starch hydrolysis, hydrolysis of tween 80, H2s production from pepton and Simmon citrate agar. All isolates showed alkali reaction on litmus milk. Isolates were negative in oxidase test, arginin hydrolysis, nitrate reduction and acetoin production. Strains were able to use arabinos, inositol, methionin, raffinose, melibiose, mannitol, mannose, sucrose, erythritol, adonitol, trihalose, salicine, dulcitol, inolin and galactose; whereas weren't able to use sorbitol. Pathogenicity test on mango' leaf, were evaluated as positive. Symptom on treated leaf was very similar to mango black spot disease. Polymerase chain reaction with two Xanthomonas specific primers (RS21, RS22) led to amplify 1Kbp fragment. Furthermore, the results of PCR product sequencing and blast search showed that these strains have 98 percent similarity to Xanthomonas citri pv. citri. On the basis of phenotypic features, pathogenicity tests and molecular results, strains identified as Xanthomonas citri pv. mangiferaeindicae. This is the first report of mango bacterial black spot caused by X. citri pv. mangiferaeindicae in Iran.