CHARACTERIZATION AND IDENTIFICATION OF BACTERIA ISOLATED FROM MICROPROPAGATED MINT PLANTS

Bacterial isolates from contaminated mint shoot cultures were characte rized and identified as a preliminary step in determining an eliminati on treatment. The 22 bacteria were characterized using biochemical and morphological tests and subjected to sensitivity tests with four anti biotics. The isolates were compared with known organisms and assigned to genera according to similarities in characteristics. Seven isolates were analyzed by fatty acid analysis carried out by a commercial labo ratory. Six were classified as Agrobacterium radiobacter; eight as Xan thomonas; one each as Pseudomonos fluorescens, Micrococcus spp., Coryn ebacterium spp., and Curtobacterium spp.; four could not be assigned t o genera. Inhibition of growth of the bacteria by most antibiotics was best at pH 7.5. Minimal inhibitory concentration and minimal bacteric idal concentrations of gentamicin, rifampicin, streptomycin sulfate, a nd Timentin varied with genotype.