Table 2
Differential characteristics between strain HHU K3-1T and closely related species.
Taxa: 1, Actirhodobacter atrilutea HHU K3-1T ; 2, Parapontixanthobacter aurantiacus MCCC 1A09962T ; 3, Pelagerythrobacter marensis KCTC 22370T.
Characteristic
|
1
|
2
|
3
|
Colony colour
|
orange
|
orange
|
yellow
|
Optimum temperature
|
28 ℃
|
28 ℃
|
28 ℃
|
Optimum NaCl (%, w/v)
|
1-3
|
3
|
0.5-5
|
Optimum pH
|
7
|
8
|
6-8
|
Assimilation of:
|
|
|
|
L-arabinose
|
-
|
+
|
-
|
malic acid
|
-
|
-
|
+
|
Enzyme activities:
|
|
|
|
valine arylamidase
|
-
|
+
|
+
|
cystine arylamidase
|
-
|
+
|
-
|
trypsin
|
-
|
+
|
-
|
Diagnostic phospholipidsa
|
DPG, PE, PG, SGL, GL, PL, L
|
DPG, PE, PG, SGL, GL, L
|
DPG, PE, PG, SGL, PL, L
|
DNA G + C content (mol%)
|
62.1
|
56.9
|
63.1
|
DPG, diphosphatidylglycerol; PE, phosphatidylethanolamine; PG, phosphatidylglycerol; SGL, sphingoglycolipid; GL, unidentified glycolipid; PL, unidentified phospholipid; L, unidentified lipid.
|
Chemotaxonomic characterization
The total cellular fatty acids of strain HHU K3-1T and its most related species were shown in Table S1. The predominant fatty acids (>10% of the total fatty acids) of strain HHU K3-1T were summed feature 8 (C18:1ω7c/C18:1ω6c) (33.5%), C17:1ω6c (24.0%) and summed feature 3 (C16:1ω7c/C16:1ω6c) (12.3%). The major polar lipid of strain HHU K3-1T were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and sphingoglycolipid (SGL), which is similar to those of the closely related type strains Ppb. aurantiacus MCCC 1A09962T and Pel. marensis KCTC 22370T. In addition, two unknown phospholipid and one unidentified lipid were also detected. The major respiratory quinone of strain HHU K3-1T was ubiquinone-10, which is common in the species of the genus Altererythrobacter and other genera (Feng et al. 2015).
On the basis of phylogenetic, phenotypic and chemotaxonomic data, strain HHU K3-1T should be proposed as a novel genus within the family Erythrobacteraceae, for which the name Actirhodobacter atrilutea gen. nov., sp. nov. is proposed.
Description of Actirhodobacter gen. nov.
Actirhodobacter (Ac.ti.rhodobac’ter L. fem. n. acta, ae seaside, shore; Gr. neut. n. rhodon, the rose; N.L. masc. n. bacter, rod; N.L. masc. n. Actirhodobacter, red-colored rod from the seaside)
Cells are Gram-staining-negative, non-motile, aerobic and have no soluble pigments. Colonies are orange, smooth and opaque. The dominant respiratory quinone is ubiquinone-10. The major polar lipids are diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and sphingoglycolipid (SGL). The genomic G+C content is 62.1 mol%. As determined by 16S rRNA gene sequence analysis, the genus is a member of the family Erythrobacteraceae, class Alphaproteobacteria. The type species is Actirhodobacteratrilutea.
Description of Actirhodobacteratrilutea sp. nov.
Actirhodobacteratrilutea (at.ri.lu’te.a L. adj. ater-tra-trum dark; L. adj. luteus -a -um orange; N.L. fem. adj. atrilutea dark orange)
Cells are Gram-stain-negative, non-motile and aerobic. After incubation on 2216E agar for 3 days. Colonies are orange, smooth and opaque. Growth occurs at 28-37℃, at pH 6-8 (optimum pH 7.0) and in the presence of NaCl concentrations of 0.5-5% (optimum 2 %). Oxidase- and catalase-positive. Positive for acid phosphatase, alkaline phosphatase, esterase (C4), esterase lipase (C8), leucine arylamidase, naphthol-AS-BI-phosphohydrolase and α-chymotrypsin, but negative for cystine arylamidase, lipase (C14), N-acetyl-β-glucosaminidase, trypsin, valine arylamidase, α-fucosidase, α-galactosidase, α-glucosidase, α-mannosidase, β-galactosidase, β-glucosidase and β-glucuronidase. In addition, Cells are positive for catalase, oxidase and hydrolysis of esculin, but negative for arginine dihydrolase, D-glucose fermentation, indole production, hydrolysis of urea and gelatin, nitrate reduction and 4-nitrophenyl β-D-galactopyranoside and could not assimilate adipic acid, capric acid, D-glucose, D-maltose, D-mannitol, D-mannose, L-arabinose, malic acid, N-acetylglucosamine, phenylacetic acid, potassium gluconate, and trisodium citrate. Positive for utilization of acetic acid, acetoacetic acid, L-glutamic acid, tween 40 and was resistant to nalidixic acid. The predominant respiratory quinone is ubiquinone-10, The major polar lipids are diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and sphingoglycolipid (SGL), two unknown phospholipid and one unidentified lipid. The predominant fatty acids (>5%) were summed feature 8 (C18:1ω7c/C18:1ω6c), C17:1ω6c, summed feature 3 (C16:1ω7c/C16:1ω6c) and C16:0.
The type strain, HHU K3-1T (=MCCC 1K04225T = KCTC 72834T = CGMCC 1.17395T), was isolated from the surface water of Yellow Sea, China. The DNA G+C content is 62.1 mol%.
The 16S rRNA gene sequence has been deposited at GenBank/EMBL/DDBJ accession number MW172823, while the genome sequence has been deposited at GenBank/EMBL/DDBJ under accession number JABWGV000000000.