Seedborne Bacteria of Orange and Black Colour Carrots in Turkey

Carrot (Daucus carota L.) is among the most economically important vegetable crops worldwide. Seedborne bacterial pathogens of carrot cause important damages to seed quality and yield of plants. In this study, seedborne bacteria were determined on some carrot seeds sown in Turkey. Seeds of different orange and black color varieties of carrot were collected from Eregli and Kasınhanı districts of Konya province, where the highest carrot production is reported. Subsamples of 10,000 seeds were soaked in 100 ml sterile saline (0.85% NaCl) with 0.02% Tween 20 overnight at 5 °C, YDCA, KB, MKM, MD5A and mTBM media were used for bacterial isolation and bacterial morphological characterization. Biochemical, physiological and molecular methods were used for the identification of the bacterial isolates. Pathogenicity tests of strains were performed on orange color carrots, and pathogenic strains induced a hypersensitive reaction in tobacco plants. The 60 pathogenic and saprophytic bacterial strains were obtained belong to Pseudomonaceae, Bacillaceae, and Xanthomonadaceae families. There were twenty-three seed samples on 5 different orange carrot cultivars Maestro, Bolero, Sireco, Natuna and Romans, and 11 black carrot genotype of traditional cultivar ‘Eregli’. Two pathogenic bacteria were defined as Xanthomonas hortorum pv. carotae and Pseudomonas viridiflava at different percent infestation ratios (17.39-18.18%) and (9.09-13.04%) on orange and black carrot seed samples. To the best of our knowledge, it is the first report of P. viridiflava on carrot seeds in Turkey.