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Two novel Gram-stain-positive bacteria, designated as SCSIO 52909 T and SCSIO 52915 T , were isolated from a deep-sea sediment sample collected at about 3448 m water depth of the South China Sea. Phenotypic, chemotaxonomic and genomic characteristics were investigated. These strains were aerobic and tested positive for catalase activity, oxidase activity and nitrate reduction. Optimal growth occurred at 28 °C, pH 7 and 3% salinity over 14 days cultivation. Its peptidoglycan structure was type A3α (l-Lys-l-Ala) and the only menaquinone was MK-8. Both strains possessed diphosphatidylglycerol, phosphatidylglycerol, an unidentified phosphoglycolipid, an unidentified glycolipid and an unidentified phospholipid. Their major fatty acids differed, but both contained iso-branched components of C 16 : 0 12-methyl. Genome sequencing revealed two large genomes of 4.58 Mbp with G+C content of 67.0 mol% in SCSIO 52909 T and of 4.42 Mbp with G+C content of 69.1 % in SCSIO 52915 T . The two novel strains encoded genes for metabolism that are absent in most other Rubrobacter species, and possessed many more gene copy numbers of alkaline phosphatase and thioredoxin reductase. Results of gANI and 16S rRNA gene analyses suggested that the two strains represent two new species, with 74.9, 95.0 % pairwise similarity between each other, and less than 74.3 and 93.5 % to other recognized Rubrobacter species, respectively. In the phylogenetic analysis, strains SCSIO 52909 T and SCSIO 52915 T were separately clustered together and formed a well-separated phylogenetic branch distinct from the other known species in the genus Rubrobacter . Based on the data presented here, these two strains should be recognized as two new species in the genus Rubrobacter , for which the names Rubrobacter tropicus sp. nov., with the type strain SCSIO 52909 T (=KCTC 49412 T =CGMCC 1.13853 T ), and Rubrobacter marinus sp. nov., with the type strain SCSIO 52915 T (=KCTC 49411 T =CGMCC 1.13852 T ), are proposed.

A novel Gram-stain-negative bacterium, designated as SCSIO 06110 T , was isolated from a deep-sea sediment of the West Pacific Ocean. Cells were 0.5-0.8 µm in width and 3.0-4.0 µm in length, spore-forming, rod-shaped with peritrichous flagella. Positive for catalase and urease, negative for oxidase and nitrate reduction. Growth occurred at 15-37 °C, pH 6-9 and 1-5 % (w/v) NaCl, with optimum growth at 28 °C, pH 7 and 3 % (w/v) NaCl. MK-7 was the only menaquinone. The strain possessed diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and two unidentified phospholipids. Iso-C 16 : 0 , iso-C 15 : 0 and iso-C 14 : 0 were the major fatty acids. The novel isolate clustered with genera in the family Paenibacillaceae , but formed a separated branch with the closest relative Chengkuizengella sediminis J15A17 T (91.1 % sequence similarity) when compared in a phylogenetic analysis of 16S rRNA gene sequences. The DNA G+C content of strain SCSIO 06110 T was 38.5 mol%. Based on the polyphasic data presented, a new genus, Longirhabdus gen. nov., is proposed in the family Paenibacillaceae with the type species Longirhabdus pacifica sp. nov. and the type strain SCSIO 06110 T (=DSM 105158 T =CGMCC 1.16550 T ).

A novel bacterium, designated SCSIO 07575 T , was isolated from a deep-sea hydrothermal sediment sample collected from the western Pacific Ocean. Growth at 65 °C was observed, but not at 70   °C or below 37 °C. The optimum conditions for growth were at 55-65 °C, pH 7.0 and in the presence of 2 % (w/v) NaCl. Strain SCSIO 07575 T showed filamentous growth. Unstable formation of white aerial mycelia was observed, which disappeared after several times' subculture. Abundant substrate mycelia were observed with grape-like spores. No soluble pigment was observed. Phylogenetic analysis of 16S rRNA gene sequences showed that SCSIO 07575 T belonged to the family Thermoactinomycetaceae and formed a distinct clade in the phylogenetic tree. The cell-wall peptidoglycan contained meso-diaminopimelic acid. Whole-cell hydrolysates contained ribose, xylose, glucose and galactose. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid and two unidentified phospholipids. The predominant menaquinone was MK-7. Major fatty acids were iso-C15 : 0, iso-C17 : 0 and iso-C16 : 0. Based on the whole genome sequence analysis, the genome size was 2 751 094 bp with a DNA G+C value of 57.2 mol%, including one circular chromosome and one plasmid. On the basis of polyphasic data, strain SCSIO 07575 T represented a novel species of a new genus within the family Thermoactinomycetaceae, for which the name Staphylospora gen. nov. is proposed with the type species Staphylospora marina sp. nov. and the type strain SCSIO 07575 T (=DSM 106793 T =CGMCC 1.15879 T ).