Identification of pathogenic bacteria in tomato fields of Urmia

Several pathogenic prokaryote agents affect tomato cultivation in fields around Urmia. In some cases, the damage to these agents is so high and farms are released. Tomato fields located around Urmia were visited during July to September 2015 and 2016. Sampling was carried out from infected plants with leaf necrosis, water soaking and canker symptoms. After isolation and purification of 183 isolates, hypersensitive reaction test was done on tobacco and four o’clock flower leaves, and pathogenicity of positive HR isolates were experimented on tomato plants. Phenotypic tests such as Gram staining, obligate aerobic, motility, oxidase, catalase, potato soft rot, lecithinase, levan, fluorescent pigment producing, tolerance of 4, 5 and 7% NaCl, ketolactose, starch hydrolysis, Tween 80 hydrolysis, esculin hydrolysis, casein hydrolysis, arginine dihydrolase, growth at 4 and 40 °C, utilization of some carbohydrate sources like sorbitol, ribose, inuline, acetate and fumarate, growth on TTC and CNS media were carried out on studied isolates. Based on the results of mentioned phenotypical experiments and using validated bacteriology references, presence of Gram positive bacterium Clavibacter michiganensis subsp. michiganensis and some Gram negative bacteria with different characters belong to fluorescent and non- fluorescent Pseudomonas among studied bacteria were proven. In order to complete the identification experiment of studied bacteria, molecular tests such as polymerase chain reaction using universal primers of 16S rRNA gene are ongoing.

Keywords:

Tomato , Prokaryote , Phenotypic , Biochemical , Urmia