Prevalance of grapevine crown gall disease agents Rhizobium vitis and Rhizobium radiobacter in vineyard areas of thrace region and determination of susceptibility of some grapevine varieties against disease agents

Surveys were carried out to determine presence of grapevine crown gall disease agents Rhizobium vitis and R. radiobacter from the vineyards in Tekirdağ, Edirne and Kırklareli provinces during May-June and July-August of 2016-2019. A total of 171 isolates, which grown as R. vitis and R. radiobacter bacterial colonies on RS, King's B and PDA media, were obtained from the gall, root and vascular tissues of diseased grape plants. The pathogenicity tests of isolates were practised on carrot slices (Daucus corata), tomato (Lycopersicon esculentum cv. Heinz 2274), kalonche (Kalonchoe daigramontiana), thorn apple (Datura stromonium), Narince, Papazkarası and Trakya İlkeren grape variety plants. Among tested, 171 bacterial isolates formed gall at least one indicator plant. The earliest and the most severe galls were observed on the carrot disks. R. vitis and R. radiobacter species division were carried out based on biochemical and physiological test results and 11 re-isolates were given unexpected results. Chosen three provinces isolated genomic DNA of 28 R. vitis and 20 R. radiobacter were applied using PCR analysis to identify R. vitis and R. radiobacter. After the results of PCR assay, only one R. radiobacter re-isolates were not yielded visual amplicons with VCF/VCR primer pairs. Tumorogenic R. vitis re-isolates chosen from three provinces were identified by using real-time PCR analysis with virD2F/virD2R primer pairs and probe. After the results of classical identification and PCR analysis 111 isolates were identified as R. vitis, 49 were identified as R. radiobacter among 160 isolates. The average rate of R. vitis prevalance were determined in Tekirdağ 65,91%, Edirne 80,21% and Kırklareli 88,86%. Rhizobium radiobacter avarage rate of disease prevalences were determined in Tekirdağ 26%, Edirne 15,97% and Kırklareli 46,66%. R. vitis and R. radiobacter susceptibility of the cultivar of grapes grafted 5BB and 8B rootstocks Narince, Trakya İlkeren ve Papazkarası were evaluated statistically according to obtained average gall diameters and gall weights; isolates and grape varieties were found effective at the end of ANOVA analysis. After performing Duncan test grouping were made, Narince was determined the most sensitive, Trakya İlkeren were determined the most tolerant.