الفهرس 
Materials and methodsOnly 14 pages are availabe for public view
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Abstract
This study try to improve the symbiotic phenotype in Rhizobium leguminosarum bv. phaseoli, which loss in this strain due to changes in the structure of its Sym plasmid, which involved in different rearrangements, which modify the information it carries. The symbiotic instability of these R. phaseoli strains is due to genetic rearrangements caused by the presence of reiterated sequences. Conjugal transfer of DNA was carried out in this study by inducing diparental and triparental transconjugants of Rhizobium to improve the symbiotic phenotype of the microsymbiot by studying the changes in symbiotic behavior associated with the transfer of DNA via conjugation. Here, this study describe also the isolation and symbiotic characterization of Azr mutants of fast growing Rhizobium phaseoli with enhanced symbiotic nitrogen fixation capability. Triparental transconjugants were involved DNA from Pseudomonas putida to supported the role of antibiotics in disease suppression of the isolates colonize the root system to protect it against pathogens, and also to degrade phenolic compounds present in root exudates, which may affect on the suppression nodulation process, thereby improving nodulation, plant growth and yield. All new recombinants induced including transconjugants and azide resistant mutants were evaluated in pots experiments, thus leading to select the efficient strains to be evaluated under the field conditions