BACTERIAL LEAF SPOT OF Sisymbrium irio INCITED BY A CLOSELY SIMILAR PATHOVAR TO Pseudomonas syringae PV. maculicola *

KHODAYGAN, P.; RAHIMIAN, H.; SHAMSBAKHSH, M.; BARZEGAR, A.

BACTERIAL LEAF SPOT OF Sisymbrium irio INCITED BY A CLOSELY SIMILAR PATHOVAR TO Pseudomonas syringae PV. maculicola *

Document Type : Research Article

Authors

Abstract

During spring 2002, wild rocket (Sisymbrium irio) plants showing leaf spot symptoms were observed in PolorTehran province. The spots were 0.5-1.5 mm in diameter, circular to irregular brown to black, and necrotic, surrounded by faint to conspicuous chlorotic halos. A levan positive pseudomonad was isolated from the symptomatic leaves on sucrose nutrient agar (NAS). The bacterium produced fluorescent pigment on medium B of Kings B medium. From the results of biochemical and physiological characteristics, the causal bacterium was identified as a pathovar of Pseudomonas syringae. Pathogenicity of selected strains was confirmed by inoculation of wild rocket with bacterial suspension of several strains isolated from wild. In electrophoretic profile of cell proteins the strains were, partially similar to the pathotype strains of Pseudomonas syringae pv. maculicola and P. s. pv. tomato. PCR amplification with the cfl primers yielded the expected 690 bp fragment from all strains. In ERIC-BOX and REP- PCR, the fingerprints of the strains from wild rocket showed 20% similarity to those of the standard strains of P. s. pv. maculicola and P. s. pv. tomato. Nevertheless, based on their overall characteristics the strains isolated from leaf spot on S. irio may be regarded as atypical strains of P. s. pv. maculicola, pending result of further genotypic analysis.

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