Rhizobium capsici sp. nov., isolated from root tumor of a green bell pepper (Capsicum annuum var. grossum) plant

Allorhizobium terrae sp. nov., isolated from paddy soil, and reclassification of Rhizobium oryziradicis (Zhao et al. 2017) as Allorhizobium oryziradicis comb. nov

A polyphasic taxonomic approach was used to characterize a nitrogen-fixing bacterium, designated strain CC-HIH110^T, isolated from paddy soil in Taiwan. Cells of strain CC-HIH110^T were Gram-stain-negative, rod-shaped, motile with polar flagella, catalase-positive and oxidase-positive. Optimal growth occurred at 30 °С, pH 7 and 1 % NaCl. Phylogenetic analyses based on 16S rRNA genes revealed a distinct taxonomic position attained by strain CC-HIH110^T associated with Rhizobium oryziradicis (98.4 % sequence identity), Allorhizobium vitis (97.8 %), Allorhizobium taibaishanense (97.7 %) and Allorhizobium undicola (96.0 %), and lower sequence similarity to other species. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain CC-HIH110^T and the type strains of other closely related species were 71.5-88.6 % and 19.6-35.5 %, respectively. Strain CC-HIH110^T contained C_16 : 0 3-OH, C_14 : 0 3-OH/iso C_16 : 1 I and C_18 : 1 ω7c/C_{18  : 1} ω6c as the predominant fatty acids. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine, phosphatidylcholine, three unknown aminophospholipids, two unknown phospholipids and an unknown lipid. The major polyamine was homospermidine. The DNA G+C content was 55.0 mol% and the predominant quinone was ubiquinone (Q-10). Based on its distinct phylogenetic, phenotypic and chemotaxonomic traits together with results of comparative 16S rRNA gene sequence, ANI and dDDH analyses, strain CC-HIH110^T is proposed to represent a novel Allorhizobium species, for which the name Allorhizobium terrae sp. nov. (type strain CC-HIH110^T=BCRC 80932^T=JCM 31228^T). In addition, Rhizobium oryziradicis is reclassified as Allorhizobium oryziradicis (type strain N19^T=ACCC 19962^T=KCTC 52413^T) comb. nov.

Rhizobium arenae sp. nov., isolated from the sand of Desert Mu Us, China

A Gram-strain-negative, rod-shaped, motile bacterium, designated MIM27T, was isolated from the sand of the Mu Us Desert, PR China. The strain could grow at 4-45 °C (optimum, 37 °C), at pH 6.6-9.0 (optimum, 8.0) and in the presence of 0-3 % (w/v) NaCl (optimum, 0 % in RNA liquid medium). The results of phylogenetic analysis of 16S rRNA gene sequences indicated that the strain represented a member of the genus Rhizobium, with the highest similarity (96.5 %) to Rhizobium pakistanense BN-19T. The results of analysis of the sequences of the nitrogen fixation gene nifH and three housekeeping genes, recA, atpD and glnII, also indicated that MIM27T was most closely related to the species of the genus Rhizobiumwith validly published names but the similarities were low (≤90.7 %). MIM27T did not form nodules on Pisum sativum, Vicia faba, Astragalus sinicus and Phaseolus vulgaris. The major respiratory quinone of MIM27T was Q-10. The genomic DNA G+C content was 59.8 mol%. Major fatty acids of MIM27T were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C18 : 1ω7c 11-methyl, C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 2 (C12 : 0 aldehyde and/or unknown ECL 10.9525). On the basis of the physiological, chemotaxonomic and phenotypic data, MIM27T is suggested to represent a novel species of the genus Rhizobium, for which the name Rhizobium arenae sp. nov. is proposed. The type strain is MIM27T (=KCTC 52299T=MCCC 1K03215T).

Rhizobium rhizosphaerae sp. nov., a novel species isolated from rice rhizosphere

Two novel, Gram-negative, motile, rod-shaped, aerobic bacterial strains, MH17^T and RD15, were isolated from the sterilized root and rhizosphere soil of rice, respectively. Phylogenetic analysis based on 16S rRNA gene sequences showed that the similarity between strains MH17^T and RD15 was 100%. The isolates exhibit high sequence similarities to Rhizobium oryzae CGMCC 1.7048^T (98.7%) and Rhizobium petrolearium SL-1^T (97.0% and 97.1%), which supports that they belong to a novel species in the genus Rhizobium. Strains MH17^T and RD15 exhibited growth at 15-45 °C, pH 5.0-11.0, 0-2.0% sodium chloride (w/v). Sequence analysis of housekeeping genes gyrB, recA, atpD, ropB, gltA showed that these two novel strains had less than 94% similarity with the known species, indicating the distinct position of MH17^T and RD15 in the genus Rhizobium. The major cellular fatty acids were identified as summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). Type strain MH17^T had 87.5% DNA-DNA relatedness with RD15 by using the initial renaturation rate method. Based on draft genome sequences, strain MH17^T showed 30.1% DNA-DNA hybridization values to R. oryzae CGMCC 1.7048^T, the closely related strain, which supported that MH17^T represents a novel species in the genus Rhizobium. Average nucleotide identity (ANI) between strains MH17^T and RD15 were 97.8%, and strain MH17^T showed 82.2% ANI value with R. oryzae CGMCC 1.7048^T. The DNA G+C content was 60.4 mol% (T_m). Based on physiological, biochemical characteristic, genotypic data, strains MH17^T and RD15 are concluded to represent a new species within the genus Rhizobium, for which the name Rhizobium rhizosphaerae sp. nov. is proposed. The type strain is MH17^T (=ACCC 19963^T = KCTC 52414^T).

Establishing a Role for Bacterial Cellulose in Environmental Interactions: Lessons Learned from Diverse Biofilm-Producing Proteobacteria

Bacterial cellulose (BC) serves as a molecular glue to facilitate intra- and inter-domain interactions in nature. Biosynthesis of BC-containing biofilms occurs in a variety of Proteobacteria that inhabit diverse ecological niches. The enzymatic and regulatory systems responsible for the polymerization, exportation, and regulation of BC are equally as diverse. Though the magnitude and environmental consequences of BC production are species-specific, the common role of BC-containing biofilms is to establish close contact with a preferred host to facilitate efficient host-bacteria interactions. Universally, BC aids in attachment, adherence, and subsequent colonization of a substrate. Bi-directional interactions influence host physiology, bacterial physiology, and regulation of BC biosynthesis, primarily through modulation of intracellular bis-(3'→5')-cyclic diguanylate (c-di-GMP) levels. Depending on the circumstance, BC producers exhibit a pathogenic or symbiotic relationship with plant, animal, or fungal hosts. Rhizobiaceae species colonize plant roots, Pseudomonadaceae inhabit the phyllosphere, Acetobacteriaceae associate with sugar-loving insects and inhabit the carposphere, Enterobacteriaceae use fresh produce as vehicles to infect animal hosts, and Vibrionaceae, particularly Aliivibrio fischeri, colonize the light organ of squid. This review will highlight the diversity of the biosynthesis and regulation of BC in nature by discussing various examples of Proteobacteria that use BC-containing biofilms to facilitate host-bacteria interactions. Through discussion of current data we will establish new directions for the elucidation of BC biosynthesis, its regulation and its ecophysiological roles.

List of new names and new combinations previously effectively, but not validly, published

The purpose of this announcement is to effect the valid publication of the following effectively published new names and new combinations under the procedure described in the Bacteriological Code (1990 Revision). Authors and other individuals wishing to have new names and/or combinations included in future lists should send three copies of the pertinent reprint or photocopies thereof, or an electronic copy of the published paper to the IJSEM Editorial Office for confirmation that all of the other requirements for valid publication have been met. It is also a requirement of IJSEM and the ICSP that authors of new species, new subspecies and new combinations provide evidence that types are deposited in two recognized culture collections in two different countries. It should be noted that the date of valid publication of these new names and combinations is the date of publication of this list, not the date of the original publication of the names and combinations. The authors of the new names and combinations are as given below. Inclusion of a name on these lists validates the publication of the name and thereby makes it available in the nomenclature of prokaryotes. The inclusion of a name on this list is not to be construed as taxonomic acceptance of the taxon to which the name is applied. Indeed, some of these names may, in time, be shown to be synonyms, or the organisms may be transferred to another genus, thus necessitating the creation of a new combination.