isolation of agrobacterium tumefaciens strains from crown gall disease on imported roses plants in qazvin province

cultivar of roses (rosa spp.) has been grown in greenhouses in qazvin region of iran for local markets. agrobacterium tumefaciens strains were isolated and identified from six different samples of roses plants imported from the netherland to iran. during august and september of 2012, nearly 2-5% of rose plants in two different greenhouses in the province of qazvin were observed with crown gall symptoms on various parts, particularly in the stem. a non-fluorescent gram-negative bacterium was consistently isolated from diseased tissues on to king's b medium. the isolated strains were confirmed asagrobacterium using different biochemical and pathogenicity (tumor forming ability) tests. four representative strains isolated were aerobic, non-sporing, non-pigmented, motile, rod-shaped, oxidase negative and catalase positive. all of four isolates were positive for tumor forming ability in pathogenicity tests on carrot disc and tomato stem.