分离自印度洋深海沉积物的部分链霉菌分离株多位点序列分析

【目的】采用多位点序列分析方法,研究印度洋3 000 m以下深海沉积物中分离得到的16S rRNA基因比对高度相似的链霉菌菌株的种间系统发育关系,同时探讨各管家基因及多基因聚类分析后的种间区分能力。【方法】以分离自印度洋深海沉积物的7株Streptomyces albidoflavus,11株Streptomyces cavourensis,16株Streptomyces pratensis为研究对象,以16S rRNA、atpD、recA和rpoB基因片段为标记,通过PCR扩增、测序,获得序列。同时从NCBI上下载5株S.pratensis上述4个基因的序列,将所有序列在MLST网站进行比对,并构建系统进化树进行比较。【结果】S.pratensis各菌株种内比较发现,16S rRNA基因构建的系统进化树中相同基因型的菌株没有聚在一起,系统进化树不稳定,区分度不高。其余3个构建的系统进化树稳定,菌株的聚类关系与MLST数据库得到的基因型一致。同时,多基因聚类分析后将菌株分为6个类群。在3个种的种间多位点序列比较中,除区分度明显增加、进化树更加稳定以外,还发现rec A基因进化上比较特殊的菌株。【结论】多位点序列分析将实验菌株分为很多不同的类型,成功地将所分离的链霉菌进行了更细的分类,同时也找到部分菌株在个别基因上差异较大。此方法可以用于相近种的快速鉴定。     

Vigna unguiculata is nodulated in Spain by endosymbionts of Genisteae legumes and by a new symbiovar (vignae) of the genus Bradyrhizobium

Vigna unguiculata was introduced into Europe from its distribution centre in Africa, and it is currently being cultivated in Mediterranean regions with adequate edapho-climatic conditions where the slow growing rhizobia nodulating this legume have not yet been studied. Previous studies based on rrs gene and ITS region analyses have shown that Bradyrhizobium yuanmingense and B. elkanii nodulated V. unguiculata in Africa, but these two species were not found in this study. Using the same phylogenetic markers it was shown that V. unguiculata, a legume from the tribe Phaseolae, was nodulated in Spain by two species of group I, B. cytisi and B. canariense, which are common endosymbionts of Genisteae in both Europe and Africa. These species have not been found to date in V. unguiculata nodules in its African distribution centres. All strains from Bradyrhizobium group I isolated in Spain belonged to the symbiovar genistearum, which is found at present only in Genisteae legumes in both Africa and Europe. V. unguiculata was also nodulated in Spain by a strain from Bradyrhizobium group II that belonged to a novel symbiovar (vignae). Some African V. unguiculata-nodulating strains also belonged to this proposed new symbiovar.     

Multilocus sequence analysis reveals multiple symbiovars within Mesorhizobium species

The genus Mesorhizobium includes species nodulating several legumes, such as chickpea, which has a high agronomic importance. Chickpea rhizobia were originally described as either Mesorhizobium ciceri or M. mediterraneum. However, rhizobia able to nodulate chickpea have been shown to belong to several different species within the genus Mesorhizobium. The present study used a multilocus sequence analysis approach to infer a high resolution phylogeny of the genus Mesorhizobium and to confirm the existence of a new chickpea nodulating genospecies. The phylogenetic structure of the Mesorhizobium clade was evaluated by sequence analysis of the 16S rRNA gene, ITS region and the five core genes atpD, dnaJ, glnA, gyrB, and recA. Phylogenies obtained with the different genes are in overall good agreement and a well-supported, almost fully resolved, phylogenetic tree was obtained using the combined data. Our phylogenetic analyses of core genes sequences and their comparison with the symbiosis gene nodC, corroborate the existence of one new chickpea Mesorhizobium genospecies and one new symbiovar, M. opportunistum sv. ciceri. Furthermore, our results show that symbiovar ciceri spreads over six species of mesorhizobia. To our knowledge this study shows the most complete Mesorhizobium multilocus phylogeny to date and contributes to the understanding of how a symbiovar may be present in different species.     

Wild peanut Arachis duranensis are nodulated by diverse and novel Bradyrhizobium species in acid soils

Aiming at learning the microsymbionts of Arachis duranensis, a diploid ancestor of cultivated peanut, genetic and symbiotic characterization of 32 isolates from root nodules of this plant grown in its new habitat Guangzhou was performed. Based upon the phylogeny of 16S rRNA, atpD and recA genes, diverse bacteria belonging to Bradyrhizobium yuanmingense, Bradyrhizobium elkanii, Bradyrhizobium iriomotense and four new lineages of Bradyrhizobium (19 isolates), Rhizobium/Agrobacterium (9 isolates), Herbaspirillum (2 isolates) and Burkholderia (2 isolates) were defined. In the nodulation test on peanut, only the bradyrhizobial strains were able to induce effective nodules. Phylogeny of nodC divided the Bradyrhizobium isolates into four lineages corresponding to the grouping results in phylogenetic analysis of housekeeping genes, suggesting that this symbiosis gene was mainly maintained by vertical gene transfer. These results demonstrate that A. duranensis is a promiscuous host preferred the Bradyrhizobium species with different symbiotic gene background as microsymbionts, and that it might have selected some native rhizobia, especially the novel lineages Bradyrhizobium sp. I and sp. II, in its new habitat Guangzhou. These findings formed a basis for further study on adaptation and evolution of symbiosis between the introduced legumes and the indigenous rhizobia.     

Heavy metal tolerant Metalliresistens boonkerdii gen. nov., sp. nov., a new genus in the family Bradyrhizobiaceae isolated from soil in Thailand

Bacterial strains from inoculated soybean field soil in Thailand were directly isolated using Bradyrhizobium japonicum selective medium (BJSM), on the basis of Zn²⁺ and Co²⁺ resistance of B. japonicum and B. elkanii. The isolates were classified into symbiotic and non-symbiotic groups by inoculation assays and Southern hybridization of nod and nif genes. In this study, a nearly full-length 16S rRNA gene sequence showed that the non-symbiotic isolates were more closely related to members of Rhodopseudomonas and to a number of uncultured bacterial clones than to members of Bradyrhizobium. Therefore, a polyphasic study was performed to determine the taxonomic positions of four representatives of the non-symbiotic isolates. Multilocus phylogenetic analysis of individual genes and a combination of the 16S rRNA and three housekeeping genes (atpD, recA and glnII) supported the placement of the non-symbiotic isolates in a different genus. The ability of heavy metal resistance in conjunction with phenotypic analyses, including cellular fatty acid content and biochemical characteristics, showed that the non-symbiotic isolates were differentiated from the other related genera in the family Bradyrhizobiaceae. Therefore, the non-symbiotic isolates represented a novel genus and species, for which the name Metalliresistens boonkerdii gen. nov., sp. nov. is proposed. The type strain is NS23 (= NBRC 106595^T = BCC 40155^T).     

Multilocus phylogenetic analysis of the genus Aeromonas

A broad multilocus phylogenetic analysis (MLPA) of the representative diversity of a genus offers the opportunity to incorporate concatenated inter-species phylogenies into bacterial systematics. Recent analyses based on single housekeeping genes have provided coherent phylogenies of Aeromonas. However, to date, a multi-gene phylogenetic analysis has never been tackled. In the present study, the intra- and inter-species phylogenetic relationships of 115 strains representing all Aeromonas species described to date were investigated by MLPA. The study included the independent analysis of seven single gene fragments (gyrB, rpoD, recA, dnaJ, gyrA, dnaX, and atpD), and the tree resulting from the concatenated 4705 bp sequence. The phylogenies obtained were consistent with each other, and clustering agreed with the Aeromonas taxonomy recognized to date. The highest clustering robustness was found for the concatenated tree (i.e. all Aeromonas species split into 100% bootstrap clusters). Both possible chronometric distortions and poor resolution encountered when using single-gene analysis were buffered in the concatenated MLPA tree. However, reliable phylogenetic species delineation required an MLPA including several “bona fide” strains representing all described species.     

Centrosema is a promiscuous legume nodulated by several new putative species and symbiovars of Bradyrhizobium in various American countries

Centrosema is an American indigenous legume that can be used in agroecosystems for recovery of acidic and degraded soils. In this study, a Centrosema-nodulating rhizobial collection of strains isolated in a poor acid savanna soil from Venezuela was characterized, and the members of the collection were compared to other Centrosema strains from America. The analysis of the rrs gene showed that the strains nodulating Centrosema in American countries were closely related to different species of the genus Bradyrhizobium. However, the analysis of the atpD and recA genes, as well as the 16S–23S ITS region, showed that they formed several new phylogenetic lineages within this genus. The Venezuela strains formed three lineages that were divergent among themselves and with respect to those formed by Centrosema strains isolated in other countries, as well as to the currently described species and genospecies of Bradyrhizobium. In addition, the symbiotic genes nodC and nifH carried by Centrosema-nodulating strains were analyzed for the first time, and it was shown that they belonged to three new phylogenetic lineages within Bradyrhizobium. The nodC genes of the Centrosema strains were divergent among themselves and with respect to the genistearum and glycinearum symbiovars, indicating that Centrosema is a promiscuous legume. According to these results, the currently known Centrosema-nodulating strains represent several new putative species and symbiovars of the genus Bradyrhizobium.     

Multilocus sequence analysis of bradyrhizobia isolated from Aeschynomene species in Senegal

This study reports the multilocus sequence analysis (MLSA) of nine house-keeping gene fragments (atpD, dnaK, glnA, glnB, gltA, gyrB, recA, rpoB and thrC) on a collection of 38 Bradyrhizobium isolated from Aeschynomene species in Senegal, which had previously been characterised by several phenotypic and genotypic techniques, allowing a comparative analysis of MLSA resolution power for species delineation in this genus. The nifH locus was also studied to compare house-keeping and symbiotic gene phylogenies and obtain insights into the unusual symbiotic properties of these Aeschynomene symbionts. Phylogenetic analyses (maximum likelihood, Bayesian) of concatenated nine loci produced a well-resolved phylogeny of the strain collection separating photosynthetic bradyrhizobial strains (PB) from non-photosynthetic bradyrhizobial (NPB) ones. The PB clade was interpreted as the remains an expanding ancient species that presently shows high diversification, giving rise to potential new species. B. denitrificans LMG8443 and BTAi1 strains formed a sub-clade that was identified as recently emerging new species. Congruence analyses (by Shimodaira–Hasegawa (S–H) tests) identified three gene-fragments (dnaK, glnB and recA) that should be preferred for MLSA analyses in Bradyrhizobium genus. The nine loci or nifH phylogenies were not correlated with the unusual symbiotic properties of PB (nod-dependent/nod-independent). Advantages and drawbacks of MLSA for species delineation in Bradyrhizobium are discussed.     

The endemic Genista versicolor from Sierra Nevada National Park in Spain is nodulated by putative new Bradyrhizobium species and a novel symbiovar (sierranevadense)

Genista versicolor is an endemic legume from Sierra Nevada National Park which constitutes one of the UNESCO-recognized Biosphere Reserves. In the present study, a collection of strains nodulating this legume was analysed in characteristic soils of this ecosystem. Most strains nodulating G. versicolor belonged to rrs group I within the genus Bradyrhizobium and only one strain, named GV137, belonged to rrs group II from which only a single species, B. retamae, has been described in Europe to date. Strain GV137, and some strains from rrs group I, belonged to putative new species of Bradyrhizobium, although most strains from group I belonged to B. canariense, according to the ITS fragment and atpD gene analysis. This result contrasted with those obtained in Genista tinctoria in Northeast Europe whose endosymbionts were identified as B. japonicum. The analysis of the symbiotic nodC and nifH genes carried by G. versicolor-nodulating strains showed that most of them belonged to symbiovar genistearum, as did those isolated from G. tinctoria. Nevertheless, strain GV137, belonging to rrs group II, formed a divergent lineage that constituted a novel symbiovar within the genus Bradyrhizobium for which the name sierranevadense is proposed. This finding showed that the Genisteae are not restrictive legumes only nodulated by symbiovar genistearum, since Genista is a promiscuous legume nodulated by at least two symbiovars of Bradyrhizobium, as occurs in Retama species.     

A new clade of Mesorhizobium nodulating Alhagi sparsifolia

We isolated 33 nodule bacteria from the legume Alhagi sparsifolia growing in the desert of northwest China. They fell into three groups by restriction analysis of their rrs (small subunit ribosomal RNA) genes, and these, together with dnaK and dnaJ genes, were sequenced from representative isolates to assess their taxonomic position by phylogenetic analysis. The bacteria in each group belonged to different lineages that might represent three different new Mesorhizobium species, two of which form a novel clade very distinct from other species in the genus. Most A. sparsifolia symbionts harboured closely related nodA and nodC genes forming new lineages. The presence of these closely related symbiosis genes in various genomic backgrounds and the incongruence observed between the different gene phylogenies indicate a history of horizontal gene transfer of symbiosis genes between the A. sparsifolia symbionts.     

Phylogenetic analysis of the pathogenic bacteria Spiroplasma penaei based on multilocus sequence analysis

A pathogenic Spiroplasma penaei strain was isolated from the hemolymph of moribund Pacific white shrimp, Penaeus vannamei. The shrimp sample originated from a shrimp farm near Cartagena, Colombia, that was suffering from high mortalities in ponds with very low salinity and high temperatures. This new emerging disease in a marine crustacean in the Americas is described as a systemic infection. The multilocus phylogenetic analysis suggests that S. penaei strain has a terrestrial origin. Evolutionary relationship trees, based on five partial DNA sequences of 16S rDNA, 23S rDNA, 5S rDNA, gyrB, rpoB genes and two complete DNA sequences of 16S-23S rDNA and 23S-5S rDNA intergenic spacer region, were reconstructed using the distance-based Neighboring-Joining (NJ) method with Kimura-2-parameter substitution model. The NJ trees based on all DNA sequences investigated in this study positioned S. penaei in the Citri-Poulsonii clade and corroborate the observations by other investigators using the 16S rDNA gene. Pairwise genetic distance calculation between sequences of spiroplasmas showed S. penaei to be closely related to Spiroplasma insolitum and distantly related to Spiroplasma sp. SHRIMP from China.     

Retama species growing in different ecological–climatic areas of northeastern Algeria have a narrow range of rhizobia that form a novel phylogenetic clade within the Bradyrhizobium genus

Sixty-seven isolates were isolated from nodules collected on roots of Mediterranean shrubby legumes Retama raetam and Retama sphaerocarpa growing in seven ecological–climatic areas of northeastern Algeria. Genetic diversity of the Retama isolates was analyzed based on genotyping by restriction fragment length polymorphism of PCR-amplified fragments of the 16S rRNA gene, the intergenic spacer (IGS) region between the 16S and 23S rRNA genes (IGS), and the symbiotic genes nifH and nodC. Eleven haplotypes assigned to the Bradyrhizobium genus were identified. Significant biogeographical differentiation of the rhizobial populations was found, but one haplotype was predominant and conserved across the sites. All isolates were able to cross-nodulate the two Retama species. Accordingly, no significant genetic differentiation of the rhizobial populations was found in relation to the host species of origin. Sequence analysis of the 16S rRNA gene grouped the isolates with Bradyrhizobium elkanii, but sequence analyses of IGS, the housekeeping genes (dnaK, glnII, recA), nifH, and nodC yielded convergent results showing that the Retama nodule isolates from the northeast of Algeria formed a single evolutionary lineage, which was well differentiated from the currently named species or well-delineated unnamed genospecies of bradyrhizobia. Therefore, this study showed that the Retama species native to northeastern Algeria were associated with a specific clade of bradyrhizobia. The Retama isolates formed three sub-groups based on IGS and housekeeping gene phylogenies, which might form three sister species within a novel bradyrhizobial clade.     

Phylogenic analysis of the genus Leishmania by cytochrome b gene sequencing

In a previous report (Luyo-Acero et al., 2004), we demonstrated that cytochrome b (Cyt b) gene analysis is an effective method for classifying several isolates of the genus Leishmania; hence, we have further applied this method to other Leishmania species in an effort to enhance the accuracy of the procedure and to construct a new phylogenic tree. In this study, a total of 30 Leishmania and Endotrypanum WHO reference strains, clinical isolates from our patients assigned to 28 strains (human and non-human pathogenic species) and two species of the genus Endotrypanum were analyzed. The Cyt b gene in each sample was amplified by PCR, and was then sequenced by several primers, as reported previously. The phylogenic tree was constructed based on the results obtained by the computer software MEGA v3.1 and PAUP* v4.0 Beta. The present phylogenic tree was almost identical to the traditional method of classification proposed by Lainson and Shaw (1987). However, it produces the following suggestions: (1) exclusion of L. (Leishmania) major from the L. (L.) tropica complex; (2) placement of L.tarentolae in the genus Sauroleishmania; (3) L. (L.) hertigi complex and L. (V.) equatorensis close to the genus Endotrypanum; (4) L. (L.) enrietti, defined as L. (L.) mexicana complex, placed in another position; and (5) L. (L.) turanica and L. (L.) arabica are located in an area far from human pathogenic Leishmania strains. Cyt b gene analysis is thus applicable to the analyzing phylogeny of the genus Leishmania and may be useful for separating non-human pathogenic species from human pathogenic species.     

MALDI-TOF mass spectrometry as a tool for differentiation of Bradyrhizobium species: Application to the identification of Lupinus nodulating strains

Genus Bradyrhizobium includes slow growing bacteria able to nodulate different legumes as well as species isolated from plant tumours. The slow growth presented by the members of this genus and the phylogenetic closeness of most of its species difficults their identification. In the present work we applied for the first time Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) to the analysis of Bradyrhizobium species after the extension of MALDI Biotyper 2.0 database with the currently valid species of this genus. With this methodology it was possible to identify strains belonging to phylogenetically closely related species of genus Bradyrhizobium allowing the discrimination among species with rrs gene identities higher than 99%. The application of MALDI-TOF MS to strains isolated from nodules of different Lupinus species in diverse geographical locations allowed their correct identification when comparing with the results of rrs gene and ITS analyses. The nodulation of Lupinus gredensis, an endemic species of the west of Spain, by B. canariense supports the European origin of this species.     

Molecular characterization of novel Bradyrhizobium strains nodulating Eriosema chinense and Flemingia vestita,important unexplored native legumes of the sub-Himalayan region (Meghalaya) of India

Root nodule bacterial strains were isolated from the little-studied legumes Eriosema chinense and Flemingia vestita (both in tribe Phaseoleae, Papilionoideae) growing in acidic soil of the sub-Himalayan region of the Indian state of Meghalaya (ME), and were identified as novel strains of Bradyrhizobium on the basis of their 16S rRNA sequences. Seven isolates selected on the basis of phenotypic characters and assessment of ARDRA and RAPD patterns were subjected to multilocus sequence analysis (MLSA) using four protein-coding housekeeping genes (glnII, recA, dnaK and gyrB). On the basis of 16S rRNA phylogeny as well as a concatenated MLSA five strains clustered in a single separate clade and two strains formed novel lineages within the genus Bradyrhizobium. The phylogenies of the symbiotic genes (nodA and nifH) were in agreement with the core gene phylogenies. It appears that genetically diverse Bradyrhizobium strains are the principal microsymbionts of these two important native legumes. The novel genotypes of Bradyrhizobium strains isolated in the present study efficiently nodulate the Phaseoloid crop species Glycine max, Vigna radiata and Vigna umbellata. These strains are genetically different from strains of Bradyrhizobium isolated earlier from a different agro-climatic region of India suggesting that the acidic nature of the soil, high precipitation and other local environmental conditions are responsible for the evolution of these newly-described Bradyrhizobium strains. In global terms, the sub-Himalayan region of India is geographically and climatically distinct and the Bradyrhizobium strains nodulating its legumes appear to be novel and potentially unique to the region.     

Multilocus sequence analysis provides basis for fast and reliable identification of Vibrio harveyi-related species and reveals previous misidentification of important marine pathogens

Vibrio harveyi and related bacteria are important pathogens responsible for severe economic losses in the aquaculture industry worldwide. Phenotypic tests and 16S rRNA gene analysis fail to discriminate species within the V. harveyi group because these are phenotypically and genetically nearly identical. This study used multilocus sequence analysis to identify 36 V. harveyi-like isolates obtained from a wide range of sources in Australia and to re-evaluate the identity of important pathogens. Phylogenies inferred from the 16S rRNA gene and five concatenated protein-coding genes (rpoA-pyrH-topA-ftsZ-mreB) revealed four well-supported clusters identified as V. harveyi, V. campbellii, V. rotiferianus and V. owensii. Results revealed that important V. campbellii and V. owensii prawn pathogens were previously misidentified as V. harveyi and also that the recently described V. communis sp. nov. is likely a junior synonym of V. owensii. Although the MLSA topologies corroborated the 16S rRNA gene phylogeny, the latter was less informative than each of the protein-coding genes taken singularly or the concatenated dataset. A two-locus phylogeny based on topA-mreB concatenated sequences was consistent with the five-locus MLSA phylogeny. Global Bayesian phylogenies inferred from topA-mreB suggested that this gene combination provides a practical yet still accurate approach for routine identification of V. harveyi-related species.     

Evaluation of the use of multilocus sequence analysis (MLSA) to resolve taxonomic conflicts within the genus Marichromatium

Four species of marine purple sulfur bacteria of the genus Marichromatium have been validly described. A recent re-analysis of the 16S rRNA-based similarity and genomic DNA–DNA hybridizations (DDH) of the type strains [33] suggested that some of them are so closely related that they can be considered heterotypic synonyms. Here, we report on the evaluation of the multilocus sequence analysis approach (MLSA) for nine Marichromatium strains in order to resolve their intrageneric genealogical relationships. MLSA was based on six protein-coding genes (gyrB, recA, fusA, dnaK, pufM, and soxB), and the results were comparable to DDH. The phylogenetic tree constructed with the concatenated sequences, which also included the 16S rRNA gene and the internal transcriber spacer ITS region (4331 bp), separated the nine strains in four lineages that reflected the four Marichromatium species. The reconstructed phylogenetic tree based on concatenation of six protein-coding genes was also highly congruent with the tree topology based on the 16S rRNA gene.     

Evaluation of seven housekeeping genes for multilocus sequence analysis of the genus Mesorhizobium: Resolving the taxonomic affiliation of the Cicer canariense rhizobia

Cicer canariense is a wild chickpea that can be nodulated by Mesorhizobium strains belonging to nine different genomic groups or genospecies. In this study, multilocus sequence analysis (MLSA) of seven protein-coding genes, recA, glnII, dnaK, rpoB, gyrB, truA and thrA, was used to resolve the phylogenetic relationships and taxonomic affiliation of 27 representative strains from all the genotypes. Individual phylogenies were mostly congruent, although there were a few discrepancies. Some genes were more discriminative than others, but concatenation of the seven genes produced a robust phylogeny of the genus Mesorhizobium. MLSA gave good support for the taxonomic affiliations of most of the genomic groups to previously recognized species and delineated several potential new species. Five genospecies found in C. canariense nodules showed average nucleotide identity values for seven genes (ANIg7) of >96% and they could be assigned to previously described Mesorhizobium species. Two large closely related genomic groups had M. caraganae as the closest species and they shared ANIg7 values in the 94–95% range, suggesting that they could be different subspecies or sister species. The predominant genospecies represented a novel monophyletic lineage that was well resolved from all currently recognized species of Mesorhizobium, with the highest ANIg7 below 92%. Other single strains represented potential new species.     

Achromobacter animicus sp. nov., Achromobacter mucicolens sp. nov., Achromobacter pulmonis sp. nov. and Achromobacter spiritinus sp. nov., from human clinical samples

The phenotypic and genotypic characteristics of fourteen human clinical Achromobacter strains representing four genogroups which were delineated by sequence analysis of nusA, eno, rpoB, gltB, lepA, nuoL and nrdA loci, demonstrated that they represent four novel Achromobacter species. The present study also characterized and provided two additional reference strains for Achromobacter ruhlandii and Achromobacter marplatensis, species for which, thus far, only single strains are publicly available, and further validated the use of 2.1% concatenated nusA, eno, rpoB, gltB, lepA, nuoL and nrdA sequence divergence as a threshold value for species delineation in this genus. Finally, although most Achromobacter species can be distinguished by biochemical characteristics, the present study also highlighted considerable phenotypic intraspecies variability and demonstrated that the type strains may be phenotypically poor representatives of the species. We propose to classify the fourteen human clinical strains as Achromobacter mucicolens sp. nov. (with strain LMG 26685^T [=CCUG 61961^T] as the type strain), Achromobacter animicus sp. nov. (with strain LMG 26690^T [=CCUG 61966^T] as the type strain), Achromobacter spiritinus sp. nov. (with strain LMG 26692^T [=CCUG 61968^T] as the type strain), and Achromobacter pulmonis sp. nov. (with strain LMG 26696^T [=CCUG 61972^T] as the type strain).