Fifty-five Chinese isolates form nodules of Amorpha fruticosa were characterized and compared with the type strains of teh species and genera of baceria which form nitrogen-fixing symbioses with teguminous host plants A polyphasic approach which inclued RFLP of PCR-amplifiod 165 rRNA genes, multiolcus enzyme elctrophoresis (MLEE) DNA-DNA hybrization 165 rRNA gene sequencing electrophorestic plasmid profiles cross-nodulation and a phenotypic study was used in teh comparatie analysis The isolated originated from several different sites in China and they varaied in their phenotypic and genetic characteristics The majority of teh isolates had moderate to slow growth rates produced acid on YMA and harboured a 930kb symbiotic plasmid (pSym) Five different RFLP patterns were idnetified among the 165 rRNA genes of all lthe isolates isolates grouped by PCR-RFLP of the 165 rRNA genes were also separated into groups by variation in MLEE profiles and by DNA-DNA hybrizdization A representatie isolate from each of these DNA homology groups had a separated position in a phylogenetic tree as determined from sequencing analyss of teh 165 rRNA genes A new species Mesorhizobium amorphae is proposed for th majority of the isolates which belonged to a moderatly slow-to slow-growing acid-producing group based upon their distinct hylogenctic position their unique electrophoretic type, their low DNA homology with reference strains representing the species within the genus Mesorhizobium and their distinct phenotypic features Strain ACCCC 19665 was cholsen as the type strain for M. amorphae sp. nov.

A novel rhizobial group cluster 9 defined in previous research Tan Z. Y., Wang E. T., Peng G. X. Zhu M.E., Martinez-ROMERO E Chen W. X. (1999) Int J Syst Bacteriol 49 1457-1469 was further characterized by determination of DNA base composition whole-cell protein SDS-PAGE analysis DNA-DNA hybridization 165 rRNA gene sequencing and host specificity These isolates were collected from the wild legumes Amphicarpaea trisperma Coronilla varia and Gueldenstaedtia multiflora growing in arid and semi-arid regions in north-wesern China lsolated within cluster 9 grouped into a single cluster above a similarity level of 90.6% in a cluster analysis based on protein SDS-PAGE and they were differentiated from defined rhizobial species comparative analysis of 165 rRNA gene sequences showed that isolate CCBAU 71623, representing cluster 9 was most related to Rhizobium gallicum and Rhizobium mongolense The DNA-DNA homologies were lower thatn 42.4% among cluster 9 and defined species including R. gallicum and R. MONGOLENSE Theese data indicated that cluster 9 was a unique genomic species lsoateds within this cluster could share their host plants They clould nt nodulate Galega orientalis and Leucarena leucocephala and formed inefeective nodulels on phaseolus vuaris This Group could also be differentiated from defined species by phenotypic characteristics it is therefore proposed as a new species Rhizobium yanglingense with isolate CCBAU 71623 as the type strain.

A total of 33 strains of fast-growing soybean rhizobia isolated from soil and soybean nodules collected in China and 25 strains beioning to the genera Rhizobium Radythizobium and Agrobacterium were compared by numerical taxonomic techniques using 240 different characters Ou resultsindicatied that all of the strains of fast-growing soybean rhizobia which we examined are closely related guanine-plus-eytosine content, 59.9 to 63.8 mol% and are separated from Rhizobium and Bradyshizobium at the generic level Based on numerical taxonomy deoxyribonucleic acid (DNA) base ratio determinations DNA-DNA hybridization data serologica analysis data the composition of extracellultar gum bacteriophage typing data and soluble rpotein patterns we propose that the fast growing soybean rhizobia represent members of a new genuw rather that a species of Rhizobium Rhizobium fredio; we propose Sinorhizobium gen nov as an appropriate generic name The type species of the new genus is Sinorhizobium fredii comb nov (basonym Rhizobium fredii Scholla and Elkan 1984) and the type strain is strain ATCC 35423 (=USDA 205) For the other species we propose the name Sinorhizobium xinjaingenis sp. Nov.; the type strain of this pecies is strain CCBAU 110, which has been deposited in the Beijing Agricultural Univesity Culture Collection Beijing People's Republic of China.

A fast-growing rhizobial group isolated from teguminous plants in Hainan Province a tropical region of China is prouposed as a new Rhizobium species on the basis of 16S rRNA gene sequencing DNA-DNA hybridization andphenotypic characterization This new species belongs to the phylogenetic branch which includes Rhizobium leguminosarum We propose the name Rhizoblum hainanense sp. Nov. for this species The strain CCBAU 57015 (166) is the type strain; it has been deposited in the cluture collection of Beijing Agricultural University People's Republic of China

Nine bacterial strains isotated from root nodules of Astragalus sinicus were compated with 41 reference strains Including the type strains of the type speciers of the genera Rhigobium Bradyrhigobium and Agrobacterium by performing a aumerical analysis of 200 henotypefeatures Represntativestrains belonging to different clusters were further compared with similar bacteria by using data from gelelectroporesis of whole-cell proteins DNA G+C content data and DNA-DNA hybridization data The rhizobial strains isolated from nodules of A Ssinicus constitute a ditincl homology group that isquite dfferent from previously described Rhizobium Radyrhizobium and Agrobacterium species and from strains isotaled from other Astragalus species we propose the name Rhizobium huakuil sp nov for the strains isolated rom A sinicus Type strain CCBAU 2609(=103) has been deposited in the Culture Collection of Beijing Agricultural University Beijing, Prople's Republic of China.