Metagenome-assembled genome of Zalaria obscura strain JY119.

Here, we report a 22.1-Mbp genome sequence of microcolonial fungi, Zalaria obscura, isolated from a pine tree bark. The microbiome of the new fungi is predicted to be largely associated with Acidobacteriota. The genome sequence of Zalaria obscura will help us in understanding the unusual relationship with Acidobacteriota member(s).

Revisiting the taxonomy of the genus Rhodopirellula with the proposal for reclassification of the genus to Rhodopirellula sensu stricto, Aporhodopirellula gen. nov., Allorhodopirellula gen. nov. and Neorhodopirellula gen. nov.

The current genus Rhodopirellula consists of marine bacteria which belong to the family Pirellulaceae of the phylum Planctomycetota. Members of the genus Rhodopirellula are aerobic, mesophiles and chemoheterotrophs. The here conducted analysis built on 16S rRNA gene sequence and multi-locus sequence analysis based phylogenomic trees suggested that the genus is subdivided into four clades. Existing Rhodopirellula species were studied extensively based on phenotypic, genomic and chemotaxonomic parameters. The heterogeneity was further confirmed by overall genome-related indices (OGRI) including digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI), average amino acid identity (AAI), and percentage of conserved proteins (POCP). AAI and POCP values between the clades of the genus Rhodopirellula were 62.2-69.6% and 49.5-62.5%, respectively. Comparative genomic approaches like pan-genome analysis and conserved signature indels (CSIs) also support the division of the clades. The genomic incoherence of the members of the genus is further supported by variations in phenotypic characteristics. Thus, with the here applied integrated comparative genomic and polyphasic approaches, we propose the reclassification of the genus Rhodopirellula to three new genera: Aporhodopirellula gen. nov., Allorhodopirellula gen. nov., and Neorhodopirellula gen. nov.

Gemmata algarum, a Novel Planctomycete Isolated from an Algal Mat, Displays Antimicrobial Activity.

Axenic cultures of two strains, JC673T and JC717, both belonging to the phylum Planctomycetota, were isolated from distinct geographical locations in India. Strain JC673T was obtained from algal mats of a wetland situated in the state of Kerala, India, while strain JC717 originated from the Central Marine Fisheries Research Institute (CMFRI), state of Tamil Nadu, India. The two strains share 99.9% 16S rRNA gene sequence similarity and are most closely related to Gemmata obscuriglobus UQM 2246T (99.3% 16S rRNA gene sequence identity). The newly isolated strains are Gram-negative, grow aerobically and tolerate up to 4% (w/v) NaCl and a pH of up to 9.0. Cells are spherical and form pink-pigmented colonies. The respiratory quinone is MK-6. Major fatty acids are C18:0, C16:1ω5c and C16:0. Polar lipids include phosphatidylcholine, phosphatidylethanolamine, several unidentified amino lipids, unidentified phospholipids, additional unidentified lipids, and an unidentified choline lipid. The polyamine spermidine is produced by the two strains. The strains have a genome size of about 8.2 Mb with a DNA G+C content of 67.6%. Solvent-based culture extracts of the isolates showed antimicrobial activity against three bacterial test strains. Their phylogenetic position along with differences in morphological, physiological, and genomic features support the classification as a new species of the genus Gemmata, for which we propose the name Gemmata algarum sp. nov. Strain JC673T (=KCTC 72851T = NBRC 114340T) and JC717 are the type and non-type strain of the new species, respectively.

Paludisphaera rhizosphaereae sp. nov., a new member of the family Isosphaeraceae, isolated from the rhizosphere soil of Erianthus ravennae.

Two axenic cultures of Planctomycetota were isolated from distinct geographical locations of India. Strain JC665T was isolated from a rhizosphere soil of Loktak lake, Manipur, whereas strain JC747 was isolated from a soil sediment at Pallikkara village, Kerala, India. The two closely related strains shared the highest 16S rRNA gene sequence identity (94.6%) with Paludisphaera borealis PX4T, while the 16S rRNA gene sequence identity between both strains was 100%. Both strains grow aerobically, stain Gram negative, colonies are light pink-coloured, cells are non-motile, spherical to oval-shaped and tolerate NaCl up to 2% (w/v). While strain JC665T grows well up to pH 9.0, strain JC747 grows only up to pH 8.0. The respiratory quinone in both strains is MK-6. C16:0, C18:1ω9c and C18:0 are the major fatty acids. Phosphatidylcholine, two unidentified glycolipids, seven unidentified lipids and two unidentified phospholipids made up the polar lipid composition of both strains. Both strains have genome sizes of about 8.0 Mb and a DNA G + C content of 66.4 mol%. Both strains contain genes coding for enzymes putatively involved in the production of lycopene-related carotenoids. The phylogenetic position together with the results of the analysis of morphological, physiological and genomic features support the classification of strain JC665T as a new species of the genus Paludisphaera, for which we propose the name Paludisphaera rhizosphaerae sp. nov. Strain JC665T (= KCTC 72671 T = NBRC 114305 T) and JC747 are the type and non-type strain of the new species, respectively.

A genomic overview including polyphasic taxonomy of Thalassoroseus pseudoceratinae gen. nov., sp. nov. isolated from a marine sponge, Pseudoceratina sp.

A pink-coloured, salt- and alkali-tolerant planctomycetal strain (JC658T) with oval to pear-shaped, motile, aerobic, Gram-negative stained cells was isolated from a marine sponge, Pseudoceratina sp. Strain JC658T shares the highest 16S rRNA gene sequence identity with Maioricimonas rarisocia Mal4T (< 89.2%) in the family Planctomycetaceae. The genomic analysis of the new strain indicates its biotechnological potential for the production of various industrially important enzymes, notably sulfatases and carbohydrate-active enzymes (CAZymes), and also potential antimicrobial compounds. Several genes encoding restriction-modification (RM) and CRISPR-CAS systems are also present. NaCl is obligate for growth, of which strain JC658T can tolerate a concentration up to 6% (w/v). Optimum pH and temperature for growth are 8.0 (range 7.0-9.0) and 25 ºC (range 10-40 °C), respectively. The major respiratory quinone of strain JC658T is MK6. Major fatty acids are C16:1ω7c/C16:1ω6c, C18:0 and C16:0. Major polar lipids are phosphatidylcholine, phosphatidyl-dimethylethanolamine and phosphatidyl-monomethylethanolamine. The genomic size of strain JC658T is 7.36 Mb with a DNA G + C content of 54.6 mol%. Based on phylogenetic, genomic (ANI, AAI, POCP, dDDH), chemotaxonomic, physiological and biochemical characteristics, we conclude that strain JC658T belongs to a novel genus and constitutes a novel species within the family Planctomycetaceae, for which we propose the name Thalassoroseus pseudoceratinae gen. nov., sp. nov. The novel species is represented by the type strain JC658T (= KCTC 72881 T = NBRC 114371 T).

Phylotaxogenomics for the Reappraisal of the Genus Roseomonas With the Creation of Six New Genera.

The genus Roseomonas is a significant group of bacteria which is invariably of great clinical and ecological importance. Previous studies have shown that the genus Roseomonas is polyphyletic in nature. Our present study focused on generating a lucid understanding of the phylogenetic framework for the re-evaluation and reclassification of the genus Roseomonas. Phylogenetic studies based on the 16S rRNA gene and 92 concatenated genes suggested that the genus is heterogeneous, forming seven major groups. Existing Roseomonas species were subjected to an array of genomic, phenotypic, and chemotaxonomic analyses in order to resolve the heterogeneity. Genomic similarity indices (dDDH and ANI) indicated that the members were well-defined at the species level. The Percentage of Conserved Proteins (POCP) and the average Amino Acid Identity (AAI) values between the groups of the genus Roseomonas and other interspersing members of the family Acetobacteraceae were below 65 and 70%, respectively. The pan-genome evaluation depicted that the pan-genome was an open type and the members shared 958 core genes. This claim of reclassification was equally supported by the phenotypic and chemotaxonomic differences between the groups. Thus, in this study, we propose to re-evaluate and reclassify the genus Roseomonas and propose six novel genera as Pararoseomonas gen. nov., Falsiroseomonas gen. nov., Paeniroseomonas gen. nov., Plastoroseomonas gen. nov., Neoroseomonas gen. nov., and Pseudoroseomonas gen. nov.

Uncovering the hidden bacterial ghost communities of yeast and experimental evidences demonstrates yeast as thriving hub for bacteria.

Our major concern was to address "yeast endobacteria" which was based on a few reports in the recent past where bacteria may find yeast as a niche for survival. In this study, we report the microbiota of twenty-nine axenic yeast cultures recovered from different habitats based on their 16S rRNA gene-amplicon metagenomes. Yeasts were identified based on D1/D2 or ITS gene sequences. Bacterial diversity was widespread, varied and rich among all yeasts except for four strains. Taxa belonging to the phylum Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes and the genera; Streptococcus, Propionibacterium were common to all the yeasts. Candida tropicalis was used as a model organism to confirm bacteria through fluorescence in situ hybridization (FISH), isolating and re-introducing the isolated bacteria into the yeast. FISH analysis confirmed the endobacteria of C. tropicalis and we have successfully isolated four bacteria only after lysis and disruption of yeast cells. These bacteria were identified as species of Pseudomonas, Chryseobacterium, Lysinibacillus and Propionibacterium. Guestimates indicate 95% of bacterial species of C. tropicalis are yet-to-be-cultivated. We have successfully reintroduced mCherry tagged Pseudomonas into C. tropicalis. Also, auto-fluorescent Prochlorococcus and Rhodopseudomonas could be introduced into C. tropicalis while mCherry tagged E. coli or Salmonella could not be introduced. FISH analysis confirmed the presence of both native and infected bacterial cells present in C. tropicalis. Our findings unveil the insights into the ghost microbiota associated with yeast, which otherwise are considered to be axenic cultures. Their inherent occurrence, together with co-cultivation experiments under laboratory conditions suggests that yeasts are a thriving hub for bacterial communities.

"Candidatus Laterigemmans baculatus" gen. nov. sp. nov., the first representative of rod shaped planctomycetes with lateral budding in the family Pirellulaceae.

Two axenic cultures of Planctomycetes were isolated from distinct geographical regions of the east coast of India. The two closely related strains (JC640 and CH01) showed <93.3% 16S rRNA gene sequence identity with members of the genus Roseimaritima followed by Rhodopirellula (<91%). Both strains displayed non-canonical cell morphology of Planctomycetes, such as rod shaped cells with division by lateral budding. Both strains showed crateriform structures on their surfaces and cells lack fimbriae. The genomes have a size of about 5.76 Mb and DNA G+C content of 63.6mol%. Phylogenetic analysis based on 16S rRNA gene sequence and 92 core genes based RAxML phylogenetic tree place both the strains in the family Pirellulaceae and indicated Roseimaritima sediminicola as their closest relative. The AAI and POCP values differentiate both strains from rest of the members of the family Pirellulaceae. The axenic cultures of both strains were able to grow up to 8-10 passages and subsequently the cells became non-viable with pleomorphic shapes. Supported by genomic, phylogenetic and morphological differences, we conclude that both strains belong to a novel genus. However, since the new isolates lost their viability on passaging, we propose the novel genus as "Candidatus Laterigemmans" gen. nov. and the novel species as "Candidatus Laterigemmans baculatus" sp. nov.

Arenibacter lacus sp. nov., Isolated from Chilika Lagoon, India.

A shiny dark yellow pigmented, Gram-stain-negative, rod-shaped, non-motile bacterium, designated as strain JC631T, was isolated from the sediment ecosystem of Chilika lagoon, India. Strain JC631T tolerates up to pH 10 and NaCl up to 3% (w/v). MK6 is the only respiratory quinone. Predominant (> 10%) cellular fatty acids are anteiso-C11:0, anteiso-C13:0, and anteiso-C15:0. Major polar lipids are phosphatidylethanolamine, phosphatidylcholine, a few unidentified phospholipids, and a few unidentified aminolipids. 16S rRNA gene sequencing showed that strain JC631T shared the highest sequence identity (98.7%) with Arenibacter latericius KMM 426T followed by Arenibacter certesii CCUG 48006T (98.6%) and other members of the genus Arenibacter (< 97%). The genome size of strain JC631T is 4.16 Mb with a GC content of 40.8 mol%. Strain JC631T has ANI scores of 78.3% and 78.1%; dDDH values of 22.2% and 21.8%, respectively, with the type strains of A. latericius and A. certesii. The genomic distinction is well supported by chemotaxonomic characteristics and differential physiological properties. This supports strain JC631T to be described as a new species of the genus Arenibacter, named as Arenibacter lacus sp. nov. The type strain is JC631T (= KCTC 72002T = NBRC 114071T).