XVI International Botanical Congess

Nitrogen fixing symbioses were established between originally asymbiotic aerobic azotobacter species and different perennial crops. The detailed characterization and further development of such valuable systems requires the incorporation of molecular markers into symbiont candidates to monitor them inside and outside their hosts. The performance of different transformation methods was evaluated using different plasmids containing selectable and screenable marker genes. The methods adapted for the preparation of competent bacteria and electroporation provided significantly more viable transformants than traditional techniques. The results also showed the integration of plasmid DNA into the host genomes. The new strains could grow on carbohydrate and nitrogen free media having normal morphological and growth characteristic. Their performance in symbiosis formation did not change and their simple in situ detection became possible.+