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In this study, a novel bacterium designated F3b2T was isolated from the gut sample of weaver ant Oecophylla smaragdina and characterised. Strain F3b2T was a Gram-negative, aerobic, non-motile, ovoid-shaped bacterium and grows optimally at 28–30 °C. Its major respiratory quinone is ubiquinone 10 (Q-10) and the major fatty acids are C18:1ω7c, C19:0 cyclo ω8c and C16:0, representing 85% of the total fatty acids. The 16S rRNA gene sequence of strain F3b2T was highest in similarity to that of Oecophyllibacter saccharovorans DSM106907T and Swingsia samuieinsis NBRC 107927T at 94.35% and 91.96%, respectively. A 16S rRNA gene-based phylogenetic analysis and a core genes-based phylogenomic analysis placed strain F3b2T in a distinct lineage in the family Acetobacteraceae. The phylogenetic placement was supported by lower than species delineation threshold average nucleotide identity (ANI) (≤ 70.2%), in silico DNA-DNA hybridization (DDH) (≤ 39.5%) and average amino acid identity (AAI) (≤ 63.5%) values between strain F3b2T and closest neighbours. These overall genome relatedness indices also supported the assignment of strain F3b2T to a novel genus within Acetobacteraceae. The genome of strain F3b2T was 1.96 Mb with 60.4% G + C DNA content. Based on these results, strain F3b2T represented a novel taxon of Acetobacteraceae, for which we proposed the name Formicincola oecophyllae gen. nov. sp. nov., and strain F3b2T (= LMG 30590T = DSM 106908T = NBRC 113640T = KCTC 62951T) as the type strain. [ABSTRACT FROM AUTHOR]

In this study, bacterial strains Ha5T, Ta1, and Jb2 were isolated from different colonies of weaver ant Oecophylla smaragdina. They were identified as bacterial symbionts of the ant belonging to family Acetobacteraceae and were distinguished as different strains based on distinctive random-amplified polymorphic DNA (RAPD) fingerprints. Cells of these bacterial strains were Gram-negative, rod-shaped, aerobic, non-motile, catalase-positive and oxidase-negative. They were able to grow at 15–37°C (optimum, 28–30°C) and in the presence of 0–1.5% (w/v) NaCl (optimum 0%). Their predominant cellular fatty acids were C18:1ω7c, C16:0, C19:0ω8c cyclo, C14:0, and C16:0 2-OH. Strains Ha5T, Ta1, and Jb2 shared highest 16S rRNA gene sequence similarity (94.56–94.63%) with Neokomagataea tanensis NBRC106556T of family Acetobacteraceae. Both 16S rRNA gene sequence-based phylogenetic analysis and core gene-based phylogenomic analysis placed them in a distinct lineage in family Acetobacteraceae. These bacterial strains shared higher than species level thresholds in multiple overall genome-relatedness indices which indicated that they belonged to the same species. In addition, they did not belong to any of the current taxa of Acetobacteraceae as they had low pairwise average nucleotide identity (< 71%), in silico DNA-DNA hybridization (< 38%) and average amino acid identity (< 67%) values with all the type members of the family. Based on these results, bacterial strains Ha5T, Ta1, and Jb2 represent a novel species of a novel genus in family Acetobacteaceae, for which we propose the name Oecophyllibacter saccharovorans gen. nov. sp. nov., and strain Ha5T as the type strain. [ABSTRACT FROM AUTHOR]

Root exudates are chemical compounds that are released from living plant roots and provide significant energy, carbon, nitrogen and phosphorus sources for microbes inhabiting the rhizosphere. The exudates shape the microflora associated with the plant, as well as influences the plant health and productivity. Therefore, a better understanding of the trophic link that is established between the plant and the associated bacteria is necessary. In this study, a comprehensive survey on the utilization of grapevine and rootstock related organic acids were conducted on a vineyard soil isolate which is Pseudomonas mendocina strain S5.2. Phenotype microarray analysis has demonstrated that this strain can utilize several organic acids including lactic acid, succinic acid, malic acid, citric acid and fumaric acid as sole growth substrates. Complete genome analysis using single molecule real-time technology revealed that the genome consists of a 5,120,146 bp circular chromosome and a 252,328 bp megaplasmid. A series of genetic determinants associated with the carbon utilization signature of the strain were subsequently identified in the chromosome. Of note, the coexistence of genes encoding several iron-sulfur cluster independent isoenzymes in the genome indicated the importance of these enzymes in the events of iron deficiency. Synteny and comparative analysis have also unraveled the unique features of d-lactate dehydrogenase of strain S5.2 in the study. Collective information of this work has provided insights on the metabolic role of this strain in vineyard soil rhizosphere. [ABSTRACT FROM AUTHOR]

Planococcus is a Gram-positive halotolerant bacterial genus in the phylum Firmicutes, commonly found in various habitats in Antarctica. Quorum quenching (QQ) is the disruption of bacterial cell-to-cell communication (known as quorum sensing), which has previously been described in mesophilic bacteria. This study demonstrated the QQ activity of a psychrotolerant strain, Planococcus versutus strain L10.15T, isolated from a soil sample obtained near an elephant seal wallow in Antarctica. Whole genome analysis of this bacterial strain revealed the presence of an N-acyl homoserine lactonase, an enzyme that hydrolyzes the ester bond of the homoserine lactone of N-acyl homoserine lactone (AHLs). Heterologous gene expression in E. coli confirmed its functions for hydrolysis of AHLs, and the gene was designated as aidP (autoinducer degrading gene from Planococcus sp.). The low temperature activity of this enzyme suggested that it is a novel and uncharacterized class of AHL lactonase. This study is the first report on QQ activity of bacteria isolated from the polar regions. [ABSTRACT FROM AUTHOR]