Background: The aim of this study was to investigate about some morphologic and molecular properties of native Sino- Rhizobium meliloti bacteria from Khorasan-Razavi.
Methods: For this purpose, bacteria were isolated from the roots of alfalfa plants that were collected from some areas of Khorasan- Razavi and examined for some biochemical properties. Morphologic properties were evaluated using stereomicroscope and electromicroscope. The plasmid profile of isolates was studied by Chen method. Molecular identification carried out by polymerase chain reaction (PCR) using specific primers of 16Sr DNA (rd1: 5'-AGAGTTTGATCCTGGCTCAG- 3', fd1: 5'-AAGGAGGTGACCAGCC- 3'). The PCR product of one sample was sequenced on both strands by using fD1and rD1 primers with an ABI 3730 XL automated DNA sequencer.
Results: All nine isolated bacteria were found to Gram-negative asporogenous rods and coccobasili. Their colonies were convex, mucoid and white to cream color and the diameter of colonies was sometimes different. Binary fission and peritrichous multiple flagella was some properties that observed by using electron microscopy. Plasmid pattern of isolates indicated two plasmids on agarose gel electrophoresis. The isolates showed a band with size 1500 bp in 1.5% gel agarose as the same reference strain using primers fd1 and rd1. DNA sequencing analysis showed similarities to the identified 16S rRNA gene from S. meliloti in the GenBank nucleotide database on the Internet at the National Center of Biotechnology Information (NCBI) website (http: //www.ncbi.nlm.nih.gov).
Conclusion: In present study, the properties of S. meliloti isolated bacteria were similar to other references and the nucleotide sequence of one sequenced isolate indicated to S. meliloti at the NCBI site.