scholarly journals Bradyrhizobia isolated from root nodules of Parasponia (Ulmaceae) do not constitute a separate coherent lineage

2006 ◽  
Vol 56 (5) ◽  
pp. 1013-1018 ◽  
Author(s):  
Bénédicte Lafay ◽  
Erika Bullier ◽  
Jeremy J. Burdon

Rhizobial bacteria almost exclusively nodulate members of the families Fabaceae, Mimosaceae and Caesalpiniaceae, but are found on a single non-legume taxon, Parasponia (Ulmaceae). Based on their host-range, their nitrogen-fixing ability and strain competition experiments, bacterial strains isolated from Parasponia were thought to constitute a separate lineage that would account for their exceptional host affinity. This hypothesis was investigated by focusing on four isolates that are representative of the morphological and cultural types of Parasponia-nodulating bradyrhizobia. Their evolutionary relationships with other rhizobia were analysed using 16S rRNA gene sequences and their nodulation properties were explored using the nodA gene as a proxy for host-range specificity. Phylogenetic analyses of the 16S rRNA and nodA gene sequences revealed that bacterial isolates from Parasponia species are embedded among other bradyrhizobia. They did not cluster together in topologies based on the 16S rRNA or nodA gene sequences, but were scattered among other bradyrhizobia belonging to either the Bradyrhizobium japonicum or the Bradyrhizobium elkanii lineages. These data suggest that the ability of some bradyrhizobia to nodulate species of the genus Parasponia does not represent a historical relationship that predates the relationship between rhizobia and legumes, but is probably a more recent host switch for some rhizobia.

2010 ◽  
Vol 60 (11) ◽  
pp. 2552-2556 ◽  
Author(s):  
Ping Fa Zhou ◽  
Wei Min Chen ◽  
Ge Hong Wei

Previously, five rhizobial strains isolated from root nodules of Robinia pseudoacacia were assigned to the same genospecies on the basis of identical 16S rRNA gene sequences and phylogenetic analyses of the nodA, nodC and nifH genes, in which the five isolates formed a well-supported group that excluded other sequences found in public databases. In this study, the 16S rRNA gene sequence similarities between the isolates and Mesorhizobium mediterraneum UPM-Ca36T and Mesorhizobium temperatum SDW018T were 99.5 and 99.6 %, respectively. The five isolates were also different from defined Mesorhizobium species using ERIC fingerprint profiles and they formed a novel Mesorhizobium lineage in phylogenetic analyses of recA and atpD gene sequences. DNA–DNA relatedness values between the representative strain, CCNWYC 115T, and type strains of defined Mesorhizobium species were found to be lower than 47.5 %. These results indicated that the isolates represented a novel genomic species. Therefore, a novel species, Mesorhizobium robiniae sp. nov., is proposed, with type strain CCNWYC 115T (=ACCC 14543T =HAMBI 3082T). Strain CCNWYC 115T can form effective nodules only on its original host.


2007 ◽  
Vol 57 (6) ◽  
pp. 1217-1221 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Sooyeon Park ◽  
Tae-Kwang Oh

Two Gram-negative, non-spore-forming, motile and helical-shaped bacterial strains, K92T and K93, were isolated from sludge from a dye works in Korea, and their taxonomic positions were investigated by means of a polyphasic approach. Strains K92T and K93 grew optimally at 37 °C and pH 7.0–8.0 in the presence of 0.5 % (w/v) NaCl. They contained Q-10 as the predominant ubiquinone and C18 : 1 ω7c as the major fatty acid. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and two unidentified amino-group-containing lipids that were ninhydrin-positive. Their DNA G+C contents were 70.0 mol%. The 16S rRNA gene sequences of K92T and K93 showed no differences, and the two strains had a mean DNA–DNA relatedness of 93 %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains K92T and K93 formed a distinct evolutionary lineage within the Alphaproteobacteria. The 16S rRNA gene sequences of strains K92T and K93 exhibited similarity values of less than 91.5 % with respect to the 16S rRNA gene sequences of other members of the Alphaproteobacteria. The two strains were distinguishable from phylogenetically related genera through differences in several phenotypic properties. On the basis of the phenotypic, phylogenetic and genetic data, strains K92T and K93 represent a novel genus and species, for which the name Caenispirillum bisanense gen. nov., sp. nov. is proposed. The type strain of Caenispirillum bisanense is K92T (=KCTC 12839T=JCM 14346T).


2005 ◽  
Vol 55 (5) ◽  
pp. 2051-2055 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Soo-Young Lee ◽  
Choong-Hwan Lee ◽  
Tae-Kwang Oh

Two Gram-negative, non-spore-forming, slightly halophilic gliding bacterial strains, DSW-8T and DSW-9, were isolated from sea water off a Korean island, Dokdo, of the East Sea, Korea, and their taxonomic position was investigated by a polyphasic study. The two strains grew optimally at 30 °C and in the presence of 2–3 % (w/v) NaCl. Strains DSW-8T and DSW-9 were characterized chemotaxonomically as containing MK-6 as the predominant menaquinone and iso-C17 : 0 3-OH, iso-C15 : 0 and iso-C15 : 1 as the major fatty acids. Major polar lipids were phosphatidylethanolamine, two unidentified phospholipids, an unidentified glycolipid and an amino group-containing lipid that was ninhydrin-positive. Their DNA G+C contents were 36·1 and 35·9 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains DSW-8T and DSW-9 fell within the genus Maribacter of the family Flavobacteriaceae. Strains DSW-8T and DSW-9 exhibited no difference in their 16S rRNA gene sequences and possessed a mean DNA–DNA relatedness level of 89 %. Strains DSW-8T and DSW-9 exhibited 16S rRNA gene sequence similarity levels of 96·9–98·0 % to the type strains of the four recognized Maribacter species, but their low level of DNA–DNA relatedness with these species demonstrated that they constitute a distinct Maribacter species. On the basis of phenotypic and phylogenetic data and genetic distinctiveness, strains DSW-8T (=KCTC 12393T=DSM 17201T) and DSW-9 were classified in the genus Maribacter as members of a novel species, for which the name Maribacter dokdonensis sp. nov. is proposed.


2011 ◽  
Vol 61 (11) ◽  
pp. 2582-2588 ◽  
Author(s):  
Fang Wang ◽  
En Tao Wang ◽  
Li Juan Wu ◽  
Xin Hua Sui ◽  
Ying Li ◽  
...  

Four bacterial strains isolated from root nodules of Phaseolus vulgaris, Mimosa pudica and Indigofera spicata plants grown in the Yunnan province of China were identified as a lineage within the genus Rhizobium according to the analysis of 16S rRNA gene sequences, sharing most similarity with Rhizobium lusitanum P1-7T (99.1 % sequence similarity) and Rhizobium rhizogenes IAM 13570T (99.0 %). These strains also formed a distinctive group from the reference strains for defined species of the genus Rhizobium in a polyphasic approach, including the phylogenetic analyses of the 16S rRNA gene and housekeeping genes (recA, atpD, glnII), DNA–DNA hybridization, BOX-PCR fingerprinting, phenotypic characterization, SDS-PAGE of whole-cell proteins, and cellular fatty acid profiles. All the data obtained in this study suggested that these strains represent a novel species of the genus Rhizobium, for which the name Rhizobium vallis sp. nov. is proposed. The DNA G+C content (mol%) of this species varied between 60.9 and 61.2 (T m). The type strain of R. vallis sp. nov. is CCBAU 65647T ( = LMG 25295T  = HAMBI 3073T), which has a DNA G+C content of 60.9 mol% and forms effective nodules on Phaseolus vulgaris.


2007 ◽  
Vol 57 (7) ◽  
pp. 1386-1390 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Soon Ei Park ◽  
So-Jung Kang ◽  
Tae-Kwang Oh

Two Gram-negative, motile, non-spore-forming bacterial strains, SW-353T and SW-369, were isolated from seawater from the East Sea, Korea, and their taxonomic positions were investigated by means of a polyphasic study. Strains SW-353T and SW-369 grew optimally at 30–37 °C and pH 7.0–8.0. Strains SW-353T and SW-369 contained Q-8 as the predominant ubiquinone and contained C16 : 0, C18 : 1 ω7c and C16 : 1 ω7c and/or iso-C15 : 0 2-OH as the major fatty acids. The DNA G+C contents were 50.1 and 50.5 mol%. Strains SW-353T and SW-369 exhibited no differences in their 16S rRNA gene sequences and showed a mean DNA–DNA relatedness level of 91 %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-353T and SW-369 belong to the genus Rheinheimera. Similarity values between the 16S rRNA gene sequences of the two isolates and the type strains of the recognized Rheinheimera species were in the range 96.6–97.9 %. DNA–DNA relatedness data and differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strains SW-353T and SW-369 differ from the recognized Rheinheimera species. On the basis of phenotypic, phylogenetic and genetic data, therefore, strains SW-353T and SW-369 represent a novel species of the genus Rheinheimera, for which the name Rheinheimera aquimaris sp. nov. is proposed. The type strain is SW-353T (=KCTC 12840T=JCM 14331T).


Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1601-1609
Author(s):  
Peng Cao ◽  
Chenxu Li ◽  
Kefei Tan ◽  
Chuanzeng Liu ◽  
Xi Xu ◽  
...  

Rice is used as a staple food in different areas of world, especially in China. In recent years, rice seedlings have been affected seriously by symptoms resembling bacterial palea browning (BPB) in Heilongjiang Province. To isolate and identify the pathogenic bacteria responsible for the disease, 40 bacterial strains were isolated from diseased rice seedlings collected from the four major accumulative-temperature zones of rice fields cultivated in Heilongjiang Province, and these were identified as 13 species based on morphological characteristics and 16S ribosomal RNA (rRNA) gene sequences. Inoculation of all the isolates on healthy rice seedlings showed that the nine Enterobacter cloacae isolates were the pathogens causing typical symptoms of BPB, including yellowing to pale browning, stunting, withering, drying, and death. Moreover, the nine E. cloacae isolates could also cause symptoms of bacterial disease on the seedlings of soybean (Glycine max), maize (Zea mays L.), and tomato (Solanum lycopersicum). Phylogenetic analysis based on the 16S rRNA gene sequences and phenotypic and biochemical characteristics indicated that these nine pathogenic isolates were E. cloacae. In addition, analysis of the sequences of four housekeeping genes (rpoB, gyrB, infB, and atpD) from the selected strain SD4L also assigned the strain to E. cloacae. Therefore, E. cloacae is the pathogen causing disease of rice seedlings in Heilongjiang Province, which we propose to classify as a form of BPB. To the best of our knowledge, this is the first study to identify E. cloacae as a causal agent of BPB in rice.


2011 ◽  
Vol 61 (5) ◽  
pp. 1182-1188 ◽  
Author(s):  
Ki-Hoon Oh ◽  
Yong-Taek Jung ◽  
Tae-Kwang Oh ◽  
Jung-Hoon Yoon

A Gram-negative-staining, non-motile and rod-shaped bacterial strain, HD-28T, was isolated from a tidal flat of the Yellow Sea, Korea. Strain HD-28T grew optimally at pH 7.0–8.0 and 30 °C in the presence of 2–3 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain HD-28T was most closely related to species of the genus Ruegeria and exhibited 95.5–96.9 % 16S rRNA gene sequence similarity to the type strains of Ruegeria species. A neighbour-joining phylogenetic tree based on gyrB gene sequences also showed that strain HD-28T fell within the cluster comprising recognized species of the genus Ruegeria, showing 77.5–83.9 % sequence similarity. Strain HD-28T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the major fatty acid. The major polar lipids detected in strain HD-28T were phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and two unidentified lipids. The DNA G+C content was 57.9 mol%. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain HD-28T could be distinguished from recognized species of the genus Ruegeria. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain HD-28T is considered to represent a novel species of the genus Ruegeria, for which the name Ruegeria faecimaris sp. nov. is proposed. The type strain is HD-28T ( = KCTC 23044T = CCUG 58878T).


2007 ◽  
Vol 57 (9) ◽  
pp. 2089-2095 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Sooyeon Park ◽  
Tae-Kwang Oh

Two Gram-negative, non-motile, pleomorphic bacterial strains, DS-40T and DS-45T, were isolated from a soil sample collected from Dokdo, Korea, and their exact taxonomic positions were investigated by using a polyphasic approach. Strains DS-40T and DS-45T grew optimally at 25 °C and pH 6.5–7.5 in the presence of 0–1.0 % (w/v) NaCl. They contained MK-7 as the predominant menaquinone and possessed iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1 ω7c and/or iso-C15 : 0 2-OH) as the major fatty acids. The DNA G+C contents of strains DS-40T and DS-45T were 36.0 and 36.8 mol%, respectively. Strains DS-40T and DS-45T shared a 16S rRNA gene sequence similarity of 96.7 % and demonstrated a mean DNA–DNA relatedness level of 12 %. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains DS-40T and DS-45T were most closely phylogenetically affiliated with the genus Pedobacter of the family Sphingobacteriaceae. Strains DS-40T and DS-45T exhibited 16S rRNA gene sequence similarity values of 91.4–93.7 and 89.9–91.6 % with respect to the type strains of Pedobacter and Sphingobacterium species, respectively. Phenotypic and chemotaxonomic properties, together with the phylogenetic data, support the assignment of strains DS-40T and DS-45T as two distinct species within the genus Pedobacter. On the basis of phenotypic, phylogenetic and genetic data, strains DS-40T and DS-45T represent two novel species of the genus Pedobacter, for which the names Pedobacter lentus sp. nov. and Pedobacter terricola sp. nov. are proposed, respectively. The respective type strains are DS-40T (=KCTC 12875T=JCM 14593T) and DS-45T (=KCTC 12876T=JCM 14594T).


2013 ◽  
Vol 63 (Pt_5) ◽  
pp. 1906-1911 ◽  
Author(s):  
Shih-Yi Sheu ◽  
Yu-Wen Shiau ◽  
Yan-Ting Wei ◽  
Wen-Ming Chen

To investigate the biodiversity of bacteria in the spring water of the Chengcing Lake Park in Taiwan, a Gram-stain-negative, rod-shaped, non-motile, non-spore-forming and aerobic bacterial strain, designated strain Chen16-4T, was isolated and characterized in a taxonomic study using a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that the closest relatives of strain Chen16-4T were Sphingobium amiense YTT, Sphingobium yanoikuyae GIFU 9882T and Sphingobium scionense WP01T, with sequence similarities of 97.6, 97.1 and 97.0 %, respectively. A phylogenetic tree obtained with 16S rRNA gene sequences indicated that strain Chen16-4T and these three closest relatives formed an independent phylogenetic clade within the genus Sphingobium . The polar lipid pattern, the presence of spermidine and ubiquinone Q-10, the predominance of C18 : 1ω7c in the cellular fatty acid profile and the DNA G+C content also supported affiliation of the isolate to the genus Sphingobium . The DNA–DNA relatedness of strain Chen16-4T with respect to recognized species of the genus Sphingobium was less than 70 %. On the basis of the genotypic, chemotaxonomic and phenotypic data, strain Chen16-4T represents a novel species in the genus Sphingobium , for which the name Sphingobium fontiphilum sp. nov. is proposed. The type strain is Chen16-4T ( = BCRC 80308T = LMG 26342T = KCTC 23559T).


2013 ◽  
Vol 63 (Pt_12) ◽  
pp. 4402-4406 ◽  
Author(s):  
Ji Young Choi ◽  
Gwangpyo Ko ◽  
Weonghwa Jheong ◽  
Geert Huys ◽  
Harald Seifert ◽  
...  

Two Gram-stain-negative, non-fermentative bacterial strains, designated 11-0202T and 11-0607, were isolated from soil in South Korea, and four others, LUH 13522, LUH 8638, LUH 10268 and LUH 10288, were isolated from a beet field in Germany, soil in the Netherlands, and sediment of integrated fish farms in Malaysia and Thailand, respectively. Based on 16S rRNA, rpoB and gyrB gene sequences, they are considered to represent a novel species of the genus Acinetobacter . Their 16S rRNA gene sequences showed greatest pairwise similarity to Acinetobacter beijerinckii NIPH 838T (97.9–98.4 %). They shared highest rpoB and gyrB gene sequence similarity with Acinetobacter johnsonii DSM 6963T and Acinetobacter bouvetii 4B02T (85.4–87.6 and 78.1–82.7 %, respectively). Strain 11-0202T displayed low DNA–DNA reassociation values (<40 %) with the most closely related species of the genus Acinetobacter . The six strains utilized azelate, 2,3-butanediol, ethanol and dl-lactate as sole carbon sources. Cellular fatty acid analyses showed similarities to profiles of related species of the genus Acinetobacter : summed feature 3 (C16 : 1ω7c, C16 : 1ω6c; 24.3–27.2 %), C18 : 1ω9c (19.9–22.1 %), C16 : 0 (15.2–22.0 %) and C12 : 0 (9.2–14.2 %). On the basis of the current findings, it is concluded that the six strains represent a novel species, for which the name Acinetobacter kookii sp. nov. is proposed. The type strain is 11-0202T ( = KCTC 32033T = JCM 18512T).


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