Eight fast-growing rhizobial isolated from xinjinag soils were identified as Sinorhizobium xinjiangense by analyses of 16S Rrna gene sequences SDS-PAGE of proteins intergenic spacer sequences an DNA-DNA hybridization. Based on all of the results these isolates and the reference strains for S. xinjianggense were a distinct genomic species although the 16S Rrna genes were closely related to that of Sinorhizobium fredii.

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.

Twenty-nine rhiizobial isolates from foot nodules of Astragatus and Lespedeza spp. growing on teh Loess Plateau of China were characterizod by numorical taxonomy RFLP and sequencing of PCR-ampilfied 16S rRNA genes measurement of DNA G+C content DNA-DNA relatedness and cross nodulaltion with selected legume species Based on teh results of umerical taxonomy the isolated formed two clusters (1 and 2) with some single isolates at a similarity tevet of 82% Ciuster 1 contained six isolated from Astragalus and Lespedeza spp. Cluster 2 consisted of nie isolated from Astragalus spp DNA relatedness was greater than 80% among isolates within cluster 2 Phylogenetic analysis based on 16S rRNA gene sequences showed taht CCBAU 7190B, reperesenting cluster 2 was cluosely related to Rhizobium galegae and Rhizobium huautlense DNA-DNA relatedness between CCBAU 7190BT and reference strains of R galegae, R. huautlense and othe related species ranged from 0 to 48.6% The cluster 2 isolates could slso be differentiated phenotypically from related species Bacsed on these data a novel species Rhizobium loessenxse sp .nov is proposed fro clustor 2 with the type strain CCBAU 7190BT (=AS1.3401T=LMG21975T).

We performed a numerical analysis of 148 phenothpic characteristics of 20 strains of root bodate bacteria isolated from an arid saline desert solt in the Xinjiang region of northwestern People's Repubtic of Chna and compared these organisms with 28 rhisobium and Bradyrhicobium strains obtained from dfferent regions of the People's Republic of China and from other eountries including nine type strains of different spectes All of the strains camined ctustered into two groups at a simitarity lesel of more than 63% Group 1 included all of previously described Rhizobium species and was divided into eight subgroups which corresponded to previously described Rhizobium species at a simitarity level of mare than 82% Group Ⅱ was divided into the following three subgroups at a similarity level ofmore than 80% Bradyhizobium japonicum a cluster containing 17 moderately and slowly growing strains isolated in the Xinjiang region and a small subgroup containing three fast-growing strains The generation times of the moderatedly and slowly growing strains were 5 to 15h, and these organisms produced acid in medium containing mannitol The DNA G+C contents of the members of theis group ranged from 59 to 63 mols DNA-DNA hybridization experiments revealed that the levels of DNA homology among all of moderately and slowly growing strains obtained from Xinjiang were more than 70% and that the levels of DNA homology between representative strains of this group and the type strains of all previousty deseribed species of root-and stem-nodulating bacteria were low All of our experimental data indicated that the moderately and slowly growing rhizobia isolated from Xinjiang are members of a new species Partial 165 rRNA gene sequencing of the type strain A-1BS(=CCBAU3306), and a comparison of the uresulting sequence with the sequences of previously described species revcaled that strain A-1BS is closely related to Rhizobium loti Rhizobium huakuii and Rhizobium galegce but not to B, japonicum and Azohizobium cantinodans On the basis of our results we propose that the strains which we studied are members of a new species Rhizobium tianshanense The type strain A-1BS(=CCBAU3306), has been deposited in the Cullure Collection of Beijing Agricultural University Beijing People's Repubilc of China.

Legume species belonging to the genus Lespecieza are annual or perennial herb or shrub plants that grow in the northern hemisphere They are known for the formation of root nodules but little in for mation is available about their microsymbionts In this study 58 root-nodule isolates from Lespedeza spp., obtained from China and the USA were characterized using muberical taxonomic analysis of phenotypic features SDS-PAGE analysis and cross-nodulation with selected legume species from the results generated using these approaches it was concluded that Lespedeza spp. were promiscuous hosts for rhizobia Four main clusters of bactera which included 35 of strains isolated from Lespedeza spp., were defined upon numerical taxonomic analysis; these groups corresponded to those determined from analyses of protein electrophoretic and DNA-DNA hybridization data The four clusters were found to define strains belonging to one of four species Sinorrhizobium saheli Bradyrhizobium japonicum Bradyrhizobium elkani or a novel species of the genus Bradyrhizobium The strains of B japonicum and B. elkanii were all from the USA soil samples and their representative strains could not nodulate soybean The seven strains found to represent the novel Bradyrhizobium sp. were from China These were differentiated from recognized species of the genus Bradyrhizobium by all of the taxonomic methods used here hence it is peoposed that the novel strains isolated from Lespedeza spp. represent a novel species of teh genus Bradyrhizobium Bradyrhizobium yuanmingense The type strain of teh novel species CCBAU 10071 (=CFNEB 101), formed ineffective nodules on Medicago sativa and Melilotus albus but did not nodulate soybean. The other 23 bacterial strains isolated from lespedeza spp. were found to form single branches or small groups (two to three strains) that were related to Bradyrhizobium mesorhizobium Rhizobium and Sinorhizobium spp. on the basis of numerical taxonomic analyss indicating the possibility that other rhizobial species are also associated with lespedeza sppo.