engleski

Genetic analysis of a nodA-nodD region of autochthonous strains of Rhizobium leguminosarum biovar viciae that showed effective nodulation of host plants

Two autochthonous strains of R. leguminosarum bv. viciae, designated 201ZG and 301ZG, were isolated from large and numerous root nodules of peas and vetches where these symbiotic bacteria fix nitrogen into ammonia. In preliminary biological experiments, both local isolates showed a better nodulation efficacy than control referent strain R. leguminosarum bv. viciae 248. The most important nodulation genes nodA and nodD, and the bidirectional promoter region between them, were cloned, sequenced and compared with the referent strain. Many changes in the primary structure of nod genes and the major promoter region were detected in both strains. Amino acid sequences of NodA and NodD proteins have changed up to 6.6% and 3.6%, respectively. The changes were conservative, however, and located at positions where variations had already been detected in both proteins. The nod boxes, which are essential to the function of the promoter region, were well conserved in both strains. The results of this study provide an insight into the primary structure of nodA-nodD region in both autochthonous strains and in the possible association with the better nodulation and nitrogen fixation which showed biological experiment in greenhouse.

nodA and nodD genes ; nodA promoter ; nitrogen fixation ; nodulation

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