Identification and characterization of Agrobacterium spp. isolated from apricot and grapevine in Serbia.

Crown gall caused by Agrobacterium spp. is a widespread bacterial disease that occurs on various agricultural crops and may cause significant economic losses. Although the disease and its causal agent are present on many cultivated plants in Serbia, Agrobacterium species have not been studied extensively for more than 30 years. We therefore investigated etiology of crown gall on particular plant hosts in Serbia and characterized the causal agent of the disease. This research was largely based on networking between our laboratory and major phytobacteriological laboratories throughout Europe within COST Actions 873 and FA0807. As a result of this collaboration, bacteria associated with crown gall symptoms on apricot trees were isolated and characterized. Based on PCR analysis, it is determined that six selected strains harbor Ti plasmids, classified as nopaline type. Tumorigenicity of the strains was confirmed in pathogenicity assay on several test plants. Using physiological and biochemical tests, multiplex PCR assay targeting 23S rRNA gene sequences and sequence analysis of the 165 rRNA gene, five strains were assigned as A. rhizogeneslbiovar 2 and the remaining one as A. tumefacienslbiovar 1. Furthermore, the joint research program led to the first report of A. vitis as the causal agent of grapevine crown gall in Serbia. The strains isolated from tumor tissue of grapevine were determined as tumorigenic and identified as A. vrlls by using classical bacteriological and molecular methods. Overall, these results provide a starting point for studying distribution, diversity and economic significance of Agrobacterium species/biovars in stone fruit and grapevine production in Serbia. This is a prerequisite for prevention of further disease spreading and successful protection. Moreover, the expertise gained during this collaboration was implemented in the research of one national project (11146008, Ministry of Education, Science and Technological Development o