Shifts in Microbial Community Structure and Co-occurrence Network along a Wide Soil Salinity Gradient

The response of microbiomes to salinity has been clarified in different geographic scales or ecosystems. However, how soil microbial community structure and interaction respond to salinity across wide salinity range and climatic region is still unclearly resolved. To address this issue, we examined the microbial community's composition in saline soils from two climatic regions (coastal wetland and arid desert). Our research confirms that soil salinity had a negative effect on soil nutrient content. Salinity decreased the relative abundance of bacteria, but increased archaea abundance, leading to the shifts from bacteria dominant community to archaea dominant community. Low-water medium-salinity soil (LWMS) had the most complex archaeal community network, whereas for bacteria, the most complex bacterial community network was observed in low-water high-salinity soils (LWHS). Key microbial taxa differed in three salinity gradients. Salinity, soil water content, pH, total nitrogen (TN), and soil organic carbon (SOC) were the main driving factors for the composition of archaeal and bacterial community. Salinity directly affected archaeal community, but indirectly influenced bacteria community through SOC; pH affected archaeal community indirectly through TN, but directly affected bacterial community. Our study suggests that soil salinity dramatically influences diversity, composition, and interactions within the microbial community.

Nocardioides cremeus sp. nov., Nocardioides abyssi sp. nov. and Nocardioides oceani sp. nov., three actinobacteria isolated from Western Pacific Ocean sediment

Three Gram-stain-positive, non-motile, short rod-shaped, catalase-positive and oxidase-negative actinomycete strains (SOB44T, SOB72T and SOB77T) were isolated from a deep-sea sediment sample collected from the Western Pacific Ocean. Cells of the three strains showed optimum growth at 30 °C and pH 7.0. Strains SOB44T, SOB72T and SOB77T could tolerate up to 10, 9 and 9 % (w/v) NaCl concentration and grow at pH 5.0-12.0, 5.0-11.0 and 5.0-11.0, respectively. Phylogenetic results based on 16S rRNA gene sequences showed that the three isolates belonged to the genus Nocardioides and were identified as representing three novel species based on 78.0-93.1 % average nucleotide identity and 21.3-50.0 % DNA-DNA hybridization values with closely related reference strains. Strains SOB44T, SOB72T and SOB77T showed highest 16S rRNA gene sequence similarity to Nocardioides salarius CL-Z59T (99.2 %), Nocardioides deserti SC8A-24T (99.2 %) and Nocardioides marmotae zg-579T (98.5 %), respectively. All three strains had MK-8(H4) as the respiratory quinone, iso-C16 : 0 as the major fatty acid, and phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol as the major polar lipids. The diagnostic diamino acid in the cell-wall peptidoglycan of all three isolates was ll-diaminopimelic acid. The DNA G+C contents of strains SOB44T, SOB72T and SOB77T were 71.1, 72.9 and 72.9 mol%, respectively. Based on the phenotypic, phylogenetic and genotypic data, strains SOB44T, SOB72T and SOB77T clearly represent three novel taxa within the genus Nocardioides, for which the names Nocardioides cremeus sp. nov. (type strain SOB44T=JCM 35774T= MCCC M28400T), Nocardioides abyssi sp. nov. (type strain SOB72T=JCM 35775T=MCCC M28318T) and Nocardioides oceani sp. nov. (type strain SOB77T=JCM 35776T=MCCC M28544T) are proposed.

Nocardioides potassii sp. nov., isolated from weathered potash tailings soil

A Gram-positive, aerobic actinomycete, designated strain KLBMP 9356^T, was isolated from weathered potash tailings soil sampled in Xuzhou, Jiangsu Province, PR China. The colonies were cream-coloured, convex and rounded. The optimal growth conditions of strain KLBMP 9356^T were 1 % (w/v) NaCl, 28 °C and pH 7. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain KLBMP 9356^T showed the highest similarity to Nocardioides zhouii CGMCC 1.11084^T (98.9 %) and Nocardioides glacieisoli CGMCC 1.11097^T (98.7 %). Results from two tree-making algorithms supported the position that strain KLBMP 9356^T forms a stable clade with N. zhouii CGMCC 1.11084^T and N. glacieisoli CGMCC 1.11097^T. Strain KLBMP 9356^T exhibited low digital DNA-DNA hybridization values with N. zhouii CGMCC 1.11084T (27.6 %) and N. glacieisoli CGMCC 1.11097^T (31.4 %). The average nucleotide identity values between strain KLBMP 9356^T and N. zhouii CGMCC 1.11084^T and N. glacieisoli CGMCC 1.11097^T were 83.8% and 85.9%, respectively. The peptidoglycan in the cell wall of the novel strain was ll-2,6-diaminopimelic acid and the predominant menaquinone was MK-8(H₄). The major fatty acids (>10 %) were C_17:1ω8c and C_18:1ω9c. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, lyso-phospatidylglycerol and phosphatidylinositol. The genomic DNA G+C content was 71.6 mol%. Based on its morphological, chemotaxonomic and phylogenetic characteristics, strain KLBMP 9356^T represents a novel species of the genus Nocardioides, for which the name Nocardioides potassii sp. nov. is proposed. The type strain is KLBMP 9356^T (=CGMCC 4.7738^T=NBRC 115493^T).

Description and genomic characterization of Nocardioides bruguierae sp. nov., isolated from Bruguiera gymnorhiza

Strains BSK12Z-3^T and BSK12Z-4, two Gram-stain-positive, aerobic, non-spore-forming strains, were isolated from Shankou Mangrove Nature Reserve, Guangxi Zhuang Autonomous Region, China. The diagnostic diamino acid in the cell-wall peptidoglycan of strain BSK12Z-3^T was LL-diaminopimelic acid and MK-8(H₄) was the predominant menaquinone. The polar lipids comprised diphosphatidylglycerol (DPG), phosphatidylglycerol (PG) and phospholipid (PL). The major fatty acids was iso-C_16:0. Phylogenetic analysis based on 16S rRNA gene sequences suggested that the two strains fell within the genus Nocardioides, appearing most closely related to Nocardioides ginkgobilobae KCTC 39594^T (97.5-97.6 % sequence similarity) and Nocardioides marinus DSM 18248^T (97.4-97.6 %). Genome-based phylogenetic analysis confirmed that strains BSK12Z-3^T and BSK12Z-4 formed a distinct phylogenetic cluster within the genus Nocardioides. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values of strains BSK12Z-3^T, BSK12Z-4 with their most related species N. marinus DSM18248^T were within the ranges of 77.2-77.3 % and 21.3-21.4 %, respectively, clearly indicated that strains BSK12Z-3^T, BSK12Z-4 represented novel species. Strains BSK12Z-3^T and BSK12Z-4 exhibited 99.9 % 16S rRNA gene sequence similarity. The ANI and dDDH values between the two strains were 97.8 % and 81.1 %, respectively, suggesting that they belong to the same species. However, DNA fingerprinting discriminated that they were not from one clonal origin. Based on phylogenomic and phylogenetic analyses coupled with phenotypic and chemotaxonomic characterizatons, strains BSK12Z-3^T and BSK12Z-4 could be classified as a novel species of the genus Nocardioides, for which the name Nocardioides bruguierae sp. nov., is proposed. The type strain is BSK12Z-3^T (=CGMCC 4.7709^T = JCM 34554^T).

Nocardioides nematodiphilus sp. nov., isolated from rhizosphere of Arabidopsis thaliana

An actinobacterial strain, designated R-N-C8T, was isolated from the rhizosphere soil of Arabidopsis thaliana collected in Yunnan Province, south-west China. Based on the results of 16S rRNA gene sequence analysis, strain R-N-C8T had highest similarity to Nocardioides terrae CGMCC 1.7056T (96.5%), Nocardioides opuntiae KCTC 19804T (96.3%) and Nocardioides currus IB-3T (96.1%), and lower than 96.0 % similarity to other members of the genus Nocardioides . Phylogenetic trees based on 16S rRNA gene sequences indicated that strain R-N-C8T formed an isolated branch with N. terrae CGMCC 1.7056T and N. opuntiae KCTC 19804T. The polar lipids contained phosphatidylglycerol, diphosphatidylglycerol, one unidentified phosphoglycolipid and four unidentified phospholipids in the cellular membrane. The major fatty acids were identified as iso-C16 : 0, anteiso-C17 : 0, iso-C17 : 0, summed feature 9 (iso-C17 : 1 ω9c and/or C16 : 0 10-methyl) and iso-C15 : 0. The predominant respiratory quinone was MK-8(H4) and ll-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The genomic DNA G+C content was 70.9 mol%. The orthologous average nucleotide identiy values between N. terrae CGMCC 1.7056T, N. currus IB-3T and strain R-N-C8T were 77.1 and 75.1 %, respectively. DNA–DNA hybridization values between N. terrae CGMCC 1.7056T, N. currus IB-3T and strain R-N-C8T were 20.7 and 19.9 % respectively. Data from phenotypic and genotypic analyses supported that strain R-N-C8T represents a new species of Nocardioides , for which the name Nocardioides nematodiphilus sp. nov. is proposed. The type strain is R-N-C8T (=CGMCC 1.18723T= KCTC 49528T).

Nocardioides coralli sp. nov., an actinobacterium isolated from stony coral in the South China Sea

A Gram-stain-positive, aerobic, non-pigmented and non-motile actinobacterium, designated strain SCSIO 67246T, was isolated from a stony coral sample collected from the Sanya sea area, Hainan province, China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SCSIO 67246T shared the highest similarities with Nocardioides rotundus MCCC 1A10561T (96.5 %) and Nocardioides sonneratiae KCTC 39565T (96.1%). The novel strain grew at 15–37 °C, at pH 5.0–10.0 and in the presence of 0–10 % (w/v) NaCl. The genome length of strain SCSIO 67246T was 3.52 Mbp with a DNA G+C content of 72.0 mol% and 3397 protein-coding genes. The novel strain showed an average nucleotide identity value of 76.5 % and a digital DNA–DNA hybridization value of 20.1 % with N. rotundus MCCC 1A10561T. Strain SCSIO 67246T contained MK-8(H4) as the major menaquinone. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and five phospholipids. The major cellular fatty acids were iso-C16 : 0, C17 : 1 ω8c and summed feature 9 (iso-C17 : 1 ω9c/10-methyl C16 : 0). ll-2,6-Diaminopimelic acid was the diagnostic diamino acid. The whole-cell sugars were galactose, glucose and ribose. Based on this polyphasic taxonomic study, strain SCSIO 67246T represents a novel species of the genus Nocardioides , for which the name Nocardioides coralli sp. nov. is proposed. The type strain is SCSIO 67246T (=MCCC 1K06251T=KCTC 49719T).

Nocardioides malaquae sp. nov., a novel actinobacterium isolated from sewage sludge of a fisheries processing factory

A Gram-stain-positive, rod-shaped, strictly aerobic bacterial strain (Y6^T) was isolated from a sewage sludge sample collected from a fisheries processing factory in Zhoushan, Zhejiang Province, PR China. The growth range of NaCl concentration was 0-6.0 % (w/v), with an optimum at 3.0 % (w/v). The temperature range for growth was 10-42 °C, with an optimum at 37 °C. The pH range for growth was pH 7.0-10.0, with an optimum at pH 9.0. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Y6^T belonged to the genus Nocardioides and showed the highest sequence similarity of 97.8 % to Nocardioides jishulii dk3136^T. The average nucleotide identity and in silico DNA-DNA hybridization values between strain Y6^T and the reference strains were 76.9-81.2 % and 20.6-23.6 %, respectively. Chemotaxonomic analysis indicated that the sole respiratory quinone was MK-8(H₄) and the predominant cellular fatty acids were iso-C_16 : 0, 10-methyl-C_17 : 0 and C_18 : 1  ω9c. The polar lipid profile was composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, four unidentified phospholipids, three unidentified aminolipids and five unidentified lipids. The peptidoglycan was ll-2,6-diaminopimelic acid. On the basis of the phenotypic, genotypic, phylogenetic and chemotaxonomic features, strain Y6^T is considered to represent a novel species, for which the name Nocardioides malaquae sp. nov. is proposed. The type strain is Y6^T (=KCTC 49504^T=MCCC 1K04765^T).

Nocardioides stalactiti sp. nov., isolated from a cave stalactite surface

An aerobic, rod-shaped, Gram-stain-positive, actinobacterial strain, designated 1.0914^T, was isolated from a stalactite sample collected from a cave located in Guizhou Province, southwest PR China. Based on 16S rRNA gene sequence analysis, strain 1.0914^T shared highest similarities values with Nocardioides pelophilus CGMCC 4.7388^T (97.7 %), Nocardioides immobilis CCTCC AB 2017083^T (97.5 %) and Nocardioides silvaticus CCTCC AB 2018079^T (97.3 %) and values lower than 97.0 % to other members of the genus Nocardioides. Phylogenetic trees based on 16S rRNA gene sequences indicated that strain 1.0914^T formed an isolated branch with N. pelophilus CGMCC 4.7388^T, N. immobilis CCTCC AB 2017083^T and N. silvaticus CCTCC AB 2018079^T. The polar lipids contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and one unidentified phospholipid in the cellular membrane. The major fatty acids were identified as iso-C_16 : 0, C_18 : 1 ω9c, C_17 : 1 ω8c and C_16 : 0. The predominant respiratory quinone was MK-8(H₄) and ll-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The genomic DNA G+C content was 71.1 mol%. The orthologous average nucleotide identiy values between N. pelophilus CGMCC 4.7388^T, N. immobilis CCTCC AB 2017083^T, N. silvaticus CCTCC 2018079^T and strain 1.0914^T were 82.3, 81.7 and 81.9 % respectively. DNA-DNA hybridization values between N. pelophilus CGMCC 4.7388^T, N. immobilis CCTCC AB 2017083^T, N. silvaticus CCTCC 2018079^T and strain 1.0914^T were 25.2, 24.6 and 24.5 % respectively. The phylogenetic, phenotypic and chemotaxonomic data supported the classification of strain 1.0914^T as representing a new species of Nocardioides, for which the name Nocardioides stalactiti sp. nov. is proposed. The type strain is 1.0914^T (=CCTCC AB 2018266^T=KCTC 49243^T).

Nocardioides jishulii sp. nov.,isolated from faeces of Tibetan gazelle (Procapra picticaudata)

Two novel Gram-stain-positive, irregular rod-shaped bacterial strains, dk3136^T and dk3543, were isolated from the faeces of Tibetan gazelle (Procapra picticaudata) in the Qinghai-Tibet Plateau of PR China. The cells were aerobic, oxidase-negative and catalase-positive. Colonies were yellowish, circular without any observable aerial mycelium after culturing at 28 ℃ for 3 days on brain-heart infusion (BHI) agar with 5 % sheep blood. The cells grew optimally at 28 °C, pH 7.5 and with 1 % (w/v) NaCl on BHI agar supplemented with 5 % sheep blood. Phylogenetic analysis of the 16S rRNA gene sequences revealed that their nearest phylogenetic relative was Nocardioides solisilvae Ka25^T (97.9 % similarity). The results of 16S rRNA gene sequence and phylogenetic/phylogenomic analyses illustrated that N. solisilvae Ka25^T, Nocardioides gilvus XZ17^T, Nocardioides houyundeii 78^T and Nocardioides daphniae D287^T were their nearest phylogenetic neighbours. The DNA G+C contents of strains dk3136^T and dk3543 were 70.3 mol% and 70.4 mol%, respectively. Their genomes exhibit lower than threshold (95-96 %) average nucleotide identity to known species of the genus Nocardioides. ll-2,6-diaminopimelic acid was the diagnostic diamino acid and MK-8(H₄) was the predominant respiratory quinone. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The two strains had C_18 : 1 ω9c, iso-C_16 : 0 and C_17 : 1 ω8c as the major fatty acids, and rhamnose and galactose as the main whole-cell sugars. On the basis of the results of our genotypic, phenotypic and biochemical analyses, we conclude that strains dk3136^T and dk3543 represent a novel species in genus Nocardioides, for which the name Nocardioides jishulii sp. nov. is proposed. The type strain is dk3136^T (=CGMCC 4.7570^T=JCM 33496^T=KCTC 49314^T).

Nocardioides dongxiaopingii sp. nov., isolated from leaves of Lamiophlomis rotata on the Qinghai-Tibet Plateau

Two novel Gram-stain-positive, irregular rod-shaped actinomycetes, S-1144^T and 4053, were isolated from leaves of Lamiophlomis rotata on the Qinghai-Tibet Plateau, PR China. Cells were aerobic, catalase-positive and oxidase-negative. Colonies on Reasoner's 2A agar were light yellow, circular, shiny, smooth and convex after 2 days of incubation. The isolates grew optimally at 25 °C, pH 7.5 and with 0 % (w/v) NaCl. The results of polyphasic analyses indicated that strain S-1144^T belonged to the genus Nocardioides and its close phylogenetic neighbours (16S rRNA gene sequence similarity) were Nocardioides litoris DSM 103718^T (98.4 %), Nocardioides rubriscoriae DSM 23986^T (98.2%) and Nocardioides plantarum DSM 11054^T (97.8 %). The genome of strain S-1144^T showed less than 70 % digital DNA-DNA hybridization and < 95-96 % average nucleotide identity values to the above reference strains. The DNA G+C content of strain S-1144^T was 73.5 mol%. MK-8(H₄) was the predominant respiratory quinone (96.0 %) and llLL-2,6-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The polar lipid profile of strain S-1144^T consisted of diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids, one unidentified glycolipid and one unidentified lipid. The major cellular fatty acids were iso-C_16 : 0, C_17 : 1  ω8c, C_17 : 0 and C_18 : 1  ω9c. On the basis of obtained data, strain S-1144^T represented a novel species of the genus Nocardioides, for which the name Nocardioides dongxiaopingii sp. nov. is proposed. The type strain is S-1144^T (=CGMCC 4.7568^T=JCM 33469^T).

Marine Rare Actinomycetes: A Promising Source of Structurally Diverse and Unique Novel Natural Products

Rare actinomycetes are prolific in the marine environment; however, knowledge about their diversity, distribution and biochemistry is limited. Marine rare actinomycetes represent a rather untapped source of chemically diverse secondary metabolites and novel bioactive compounds. In this review, we aim to summarize the present knowledge on the isolation, diversity, distribution and natural product discovery of marine rare actinomycetes reported from mid-2013 to 2017. A total of 97 new species, representing 9 novel genera and belonging to 27 families of marine rare actinomycetes have been reported, with the highest numbers of novel isolates from the families Pseudonocardiaceae, Demequinaceae, Micromonosporaceae and Nocardioidaceae. Additionally, this study reviewed 167 new bioactive compounds produced by 58 different rare actinomycete species representing 24 genera. Most of the compounds produced by the marine rare actinomycetes present antibacterial, antifungal, antiparasitic, anticancer or antimalarial activities. The highest numbers of natural products were derived from the genera Nocardiopsis, Micromonospora, Salinispora and Pseudonocardia. Members of the genus Micromonospora were revealed to be the richest source of chemically diverse and unique bioactive natural products.

Nocardioides astragali sp. nov., isolated from a nodule of wild Astragalus chrysopterus in northwestern China

A Gram-positive, non-motile, rod-shaped bacterial strain, designated HH06^T, was isolated from a nodule of Astragalus chrysopterus in northwestern China. Phylogenetic analysis of the 16S rRNA gene sequence showed that the strain is closely related to Nocardioides alpinus Cr7-14^T and Nocardioides furvisabuli DSM 18445^T with 98.5 and 98.1% similiarity, respectively. Growth was observed at 4–28 °C in R2A medium (optimum at 25 °C), at 10–30 °C in YMA and LB medium (optimum in both at 28 °C) and at pH 5.0–10.0 in R2A medium (optimum at pH 7.0–8.0). The cell wall peptidoglycan was found to contain LL-diaminopimelic acid as the principal diamino acid and MK-8(H4) was identified as the predominant menaquinone. The major polar lipids were identified as phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, two unidentified glycolipids and two unidentified polar lipids. The major fatty acids were identified as iso-C_16:0 (32.8%) and C_18:1ω9c (15.1%). The DNA G+C content of strain HH06^T was determined to be 71.4 mol%. Based on phenotypic, chemotaxonomic, phylogenetic properties and DNA–DNA relatedness, it is concluded that strain HH06^T represents a novel species of the genus Nocardioides, for which the name Nocardioides astragali sp. nov. is proposed. The type strain is HH06^T (= CGMCC 4.7327^T = NBRC 112322^T).

Nocardioides gilvus sp. nov., isolated from Namtso Lake

A Gram-stain positive, facultatively anaerobic, non-motile and rod to coccoid-shaped bacterium, designated XZ17(T), was isolated from Namtso Lake of Tibet, China. Strain XZ17(T) grew optimally at pH 8.0-9.0, at 30-33 °C and in the presence of 0-1.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that strain XZ17(T) belongs to the genus Nocardioides in the family Nocardioidaceae. Strain XZ17(T) shared pairwise 16S rRNA gene sequence similarities of 97.2, 96.8, 96.5, 96.4 and <96.0 % to Nocardioides solisilvae KCTC 39528(T), Nocardioides daejeonensis JCM 16922(T), Nocardioides jensenii NCIB 9770(T), Nocardioides dubius KCTC 9992(T) and other Nocardioides species, respectively. It contained MK-8 (H4) as the predominant menaquinone and C17:1 ω8c, C15:0, C17:0 and C18:1 ω9c as the major fatty acid. The strain had cell wall peptidoglycan based on LL-2,6-diaminopimelic acid. The polar lipids of strain XZ17(T) comprised diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids, three unidentified glycolipids and two unidentified lipids. The DNA G+C content of strain XZ17(T) was 68.9 mol%. Based on distinctive phenotypic characteristics, phylogenetic analysis and chemotaxonomic data, it can be concluded that strain XZ17(T) represents a novel species within the genus Nocardioides, for which the name Nocardioides gilvus sp. nov. is proposed. The type strain is strain XZ17(T) (=KCTC 39561(T) = MCCC 1H00114(T)).

Noncontiguous finished genome sequence and description of Nocardioides massiliensis sp. nov. GD13(T)

Nocardioides massiliensis sp. nov strain GD13^T is the type strain of N. massiliensis sp. nov., a new species within the genus Nocardioides. This strain was isolated from the faeces of a 62-year-old man admitted to intensive care for Guillain-Barré syndrome. Nocardioides massiliensis is a strictly aerobic Gram-positive rod. Herein we describe the features of this bacterium, together with the complete genome sequence and annotation. The 4 006 620 bp long genome contains 4132 protein-coding and 47 RNA genes.

Aureimonas glaciistagni sp. nov., isolated from a melt pond on Arctic sea ice

A Gram-staining-negative, motile, aerobic and rod-shaped bacterial strain, PAMC 27157T, was isolated from a melt pond on sea ice in the Chukchi Sea. Phylogenetic analysis of the 16S rRNA gene sequence of strain PAMC 27157T revealed an affiliation to the genus Aureimonas with the closest sequence similarity (96.2 %) to that of Aureimonas phyllosphaerae. Strain PAMC 27157T grew optimally at 30 °C and pH 7.0 in the presence of 3.5 % (w/v) NaCl. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmonomethylethanolamine, sulfoquinovosyldiacylglycerol and an unidentified aminolipid. The major cellular fatty acid was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c, 83.1 %) and the major respiratory quinone was Q-10. The genomic DNA G+C content was 69.1 mol%. The combined phylogenetic, phenotypic and chemotaxonomic data showed that strain PAMC 27157T could be clearly distinguished from species of the genus Aureimonas with validly published names. Thus, strain PAMC 27157T should be classified as representing a novel species in the genus Aureimonas, for which the name Aureimonas glaciistagni sp. nov. is proposed. The type strain is PAMC 27157T ( = KCCM 43049T = JCM 30183T).

Nocardioides antarcticus sp. nov., isolated from marine sediment

Strain M-SA3-94T, an aerobic, Gram-stain-positive, ovoid- to rod-shaped, non-motile bacterium, was isolated from the marine sediment of Ardley cove, King George Island, Antarctica. Strain M-SA3-94T grew optimally at pH 5.0-6.0, 20 °C and in the presence of 1.0 % (w/v) NaCl. Phylogenetic analysis, based on 16S rRNA gene sequences, indicated that strain M-SA3-94T belonged to the genus Nocardioides in the family Nocardioidaceae, clustering with Nocardioides plantarum NCIMB 12834T, Nocardioides ginsengagri BX5-10T, Nocardioides marinquilinus CL-GY44T and Nocardioides lianchengensis D94-1T (with 96.1 %, 95.9 %, 94.5 % and 94.7 % 16S rRNA gene sequence similarity, respectively). The chemotaxonomic properties of strain M-SA3-94T were similar to those of members of the genus Nocardioides with validly published names. The major fatty acid was iso-C16 : 0. The polar lipid pattern contained diphosphatidylglycerol, phosphatidylglycerol and three unknown phospholipids. The diagnostic diamino acid in the cell-wall peptidoglycan was ll-2, 6-diaminopimelic acid. MK-8(H4) was the predominant menaquinone and the DNA G+C content of this strain was 66.7 mol%. On the basis of these phenotypic, phylogenetic and chemotaxonomic data, strain M-SA3-94T represents a novel species of the genus Nocardioides, for which the name Nocardioides antarcticus sp. nov. is proposed. The type strain is M-SA3-94T ( = CCTCC AB2014053T = LMG 28254T).

Nocardioides deserti sp. nov., an actinobacterium isolated from desert soil

A rod- or coccus-shaped, non-spore-forming actinobacterium, designated strain SC8A-24T, was isolated from a soil sample collected from the rhizosphere of Alhagi sparsifolia on the southern edge of the Taklimakan desert, Xinjiang, China, and examined by a polyphasic approach to clarify its taxonomic position. This actinobacterium was Gram-staining-positive and aerobic. Substrate and aerial mycelia were not observed, and no diffusible pigments were observed on the media tested. Strain SC8A-24T grew optimally without NaCl at 28–30 °C and pH 7.0–8.0. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain SC8A-24T belonged to the genus Nocardioides and shared the highest 16S rRNA gene sequence similarity with Nocardioides salarius CL-Z59T (96.51 %), N. pyridinolyticus OS4T (96.43 %) and N. ginsengagri BX5-10T (96.37 %). The DNA G+C content of strain SC8A-24T was 71 mol%. The cell-wall peptidoglycan contained ll-2,6-diaminopimelic acid, and MK-8(H4) was the predominant menaquinone. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, an unidentified glycolipid and an unidentified phospholipid. The major fatty acids were C17 : 1ω8c, 10-methyl C17 : 0 and C18 : 1ω9c. On the basis of phylogenetic analysis and phenotypic and chemotaxonomic characteristics, strain SC8A-24T represents a novel species of the genus Nocardioides , for which the name Nocardioides deserti sp. nov. is proposed. The type strain is SC8A-24T ( = DSM 26045T = CGMCC 4.7183T).

Nocardioides soli sp. nov., a carbendazim-degrading bacterium isolated from soil under the long-term application of carbendazim

The taxonomic status of a carbendazim-degrading strain, mbc-2T, isolated from soil under the long-term application of carbendazim in China was determined by means of a polyphasic study. The cells were Gram-stain-positive, motile and rod-shaped. Strain mbc-2T grew optimally at pH 7.0, 30–35 °C and in the presence of 1 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain mbc-2T fell within the genus Nocardioides , forming a coherent cluster with the type strain of Nocardioides hankookensis , with which it exhibited 16S rRNA gene sequence similarity values of 97.9 %. The chemotaxonomic properties of strain mbc-2T were consistent with those of the genus Nocardioides : the cell-wall peptidoglycan type was based on ll-2,6-diaminopimelic acid, the predominant menaquinone was MK-8 (H4) and the major fatty acid was iso-C16 : 0. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, unknown phospholipids and an unknown aminolipid. The DNA G+C content was 72 mol%. Strain mbc-2T exhibited DNA–DNA relatedness values of 12.5±1.5 %, 23.7±2.7 % and 26.3±3.2 % with respect to Nocardioides hankookensis DS-30T, Nocardioides aquiterrae GW-9T and Nocardioides pyridinolyticus OS4T. On the basis of the data obtained, strain mbc-2T represents a novel species of the genus Nocardioides , for which the name Nocardioides soli sp. nov. is proposed. The type strain is mbc-2T ( = KACC 17152T = CCTCC AB 2012934T).

Nocardioides salsibiostraticola sp. nov., isolated from biofilm formed in coastal seawater

A Gram-staining-positive, non-motile, aerobic, non-spore-forming and short rod-shaped bacterial strain, PAMC 26527(T), was isolated from biofilm formed in coastal seawater of the Norwegian Sea. Analysis of the 16S rRNA gene sequence of strain PAMC 26527(T) revealed a clear affiliation with the genus Nocardioides. Based on phylogenetic analysis, strain PAMC 26527(T) showed the closest phylogenetic relationship with Nocardioides caricicola YC6903(T) with 16S rRNA gene sequence similarity of 96.3 %. Strain PAMC 26527(T) grew in the presence of 0-5.0 % sea salts. The optimum temperature and pH for growth were 20 °C and pH 7.5. The major cellular fatty acids of strain PAMC 26527(T) were iso-C16 : 0, C17 : 1ω8c and C18 : 1ω9c and the major isoprenoid quinone was MK-8(H4). Cell-wall analysis showed that strain PAMC 26527(T) contained LL-diaminopimelic acid. The genomic DNA G+C content was 69.3 mol%. The combined phenotypic, chemotaxonomic and phylogenetic data showed that strain PAMC 26527(T) could be clearly distinguished from recognized members of the genus Nocardioides. Thus, strain PAMC 26527(T) should be classified as representing a novel species in the genus Nocardioides, for which the name Nocardioides salsibiostraticola sp. nov. is proposed. The type strain is PAMC 26527(T) ( = KCTC 29158(T) = JCM 18743(T)).