Sequence analysis of a DNA fragment from Sinorhizobium fredii USDA257 which extends the nitrogen fixation host range of Rhizobium species NGR234 to soybean, Glycine max (L.) Merr cultivar Peking

A fragment of DNA (pBTBX) from the genome of Sinorhizobium fredii USDA257 was sequenced by shotgun strategy to identify the potential genes which enabled the Rhizobium species NGR234 to fix nitrogen on soybean, Glycine max (L.) Merr cv. Peking. The total length of the cosmid is 32,824 base pairs with a GC content of 61%. A 29 open reading frames (ORF) were identified representing 71.8% (23,574 bp) of the cosmid. Out of these ORF, 96.5% (22,749 bp) were identical and similar to reported and hypothetical genes and proteins. The remaining 3.5% (825 bp) had no apparent similarity to any genes in the data base. Gene and gene products found on the DNA fragment include those involved in the synthesis of FeMo component of nitrogenase, regulation of nitrogen fixation, transport of amino acids and sugars, chemotaxis and transcriptional regulation.