Nocardia rhizosphaerihabitans sp. nov., a novel actinomycete isolated from a coastal soil.

An actinomycete strain, designated KLBMP S0039T, was isolated from the rhizosphere soil of Lycium Linn., collected from the coastal region in Lianyungang, Jiangsu Province, eastern PR China, and was studied to determine its taxonomic position. The isolate showed a combination of morphological and chemotaxonomic properties typical of the members of the genus Nocardia. The cell wall contained meso-diaminopimelic acid as the diagnostic diamino acid and the whole-cell sugars were galactose, arabinose, glucose and ribose. The predominant menaquinone was identified as MK-8(H4ω-cycl). The diagnostic phospholipids were found to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and unknown lipids. The predominant cellular fatty acids were identified as C16 : 0, C18 : 0, C18 : 1ω9c, and 10-methyl C18 : 0 [tuberculostearic acid (TBSA)]. The G+C content of the genomic DNA was determined to be 68.2 mol%. The 16S rRNA gene sequence similarity indicated that KLBMP S0039T was most closely related to Nocardia neocaledoniensis NBRC 108232T (99.4 % 16S rRNA gene sequence similarity) and Nocardia asteroides NBRC 15531T (99.2 %), similarities to other type strains of species of the genus Nocardia were found to be less than 98.6 %. However, DNA-DNA relatedness values and phenotypic data indicated that KLBMP S0039T could be clearly distinguished from the closely related species of the genus Nocardia. On the basis of polyphasic taxonomic data, it is concluded that KLBMP S0039T represents a novel species of the genus Nocardia, for which the name Nocardiarhizosphaerihabitans sp. nov. is proposed. The type strain is KLBMP S0039T (=KCTC 39693T=CGMCC 4.7329T).

Glutamicibacter halophytocola sp. nov., an endophytic actinomycete isolated from the roots of a coastal halophyte, Limonium sinense.

A novel actinobacterium, designated KLBMP 5180T, was isolated from the surface-sterilized root of a coastal halophyte, Limonium sinense, collected from the city of Lianyungang, Jiangsu Province, eastern China. The isolate was Gram-stain-positive, aerobic and non-motile. The components of the cell-wall peptidoglycan were lysine, glutamic acid and alanine. The predominant menaquinone was MK-9. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, one unknown phospholipid, one unidentified glycolipid and two unidentified lipids. anteiso-C15 : 0 and iso-C16 : 0 were the major cellular fatty acids. The DNA G+C content of strain KLBMP 5180T was 60.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain KLBMP 5180T belongs to the genus Glutamicibacter and was related most closely to Glutamicibacter nicotianae DSM 20123T (99.3 % similarity), Glutamicibacterarilaitensis Re117T (99.3 %) and Glutamicibacter mysorens LMG 16219T (99.1 %); similarity to other type strains of the genus Glutamicibacter was lower than 98.5 %. However, DNA-DNA relatedness values between strain KLBMP 5180T, G . nicotianae DSM 20123T, G. arilaitensis Re117T and G. mysorens LMG 16219T were 47.5±2.6, 51.3±3.1 and 41.2±4.3 %, respectively. The combination of DNA-DNA hybridization, phylogenetic, phenotypic and chemotaxonomic data supported the suggestion that strain KLBMP 5180T represents a novel species of the genus Glutamicibacter, for which the name Glutamicibacterhalophytocola sp. nov. is proposed. The type strain is KLBMP 5180T (=DSM 101718T=KCTC 39692T).

Nocardiajiangsuensis sp. nov., an actinomycete isolated from coastal soil.

A novel actinomycete strain, designated strain KLBMP S0027T, was isolated from a coastal soil collected from the coastal region of Lianyungang, Jiangsu Province, in east China, and was studied in detail for its taxonomic position. Comparative 16S rRNA gene sequence analysis showed that this strain belonged to the genus Nocardia and was most closely related to Nocardia harenae WS-26T (98.5 %), Nocardiaasiatica NBRC 100129T (98.5 %), Nocardiaabscessus NBRC 100374T (98.2 %), Nocardia brasiliensis NBRC 14402T (98.2 %) and Nocardiacyriacigeorgica NBRC 100375T (98 %), respectively. The strain showed a combination of chemotaxonomic and morphological properties typical of the genus Nocardia. The cell wall contained meso-diaminopimelic acid (type IV), and whole-cell sugars were arabinose, galactose, glucose and ribose. Strain KLBMP S0027T contained MK-8(H4ω-cycl) as the predominant menaquinone; C16 : 0, C18 : 1ω9c, C18 : 0 10-methyl (TBSA) and summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) were the major cellular fatty acids. The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, one unknown glycolipid and two unknown lipids. Mycolic acids were detected. The G+C content of the DNA was 70.5 %. However, a combination of DNA-DNA hybridization and phenotypic data demonstrated that strain KLBMP S0027T could be clearly distinguished from the type strain of the most closely related species, N. harenae WS-26T. On the basis of the data presented from a polyphasic study, it was evident that this strain should be assigned to a novel species of the genus Nocardia, for which the name Nocardia jiangsuensis sp. nov. is proposed. The type strain is KLBMP S0027T (=CGMCC 4.7330T=KCTC 39691T).

Tamaricihabitans halophyticus gen. nov., sp. nov., an endophytic actinomycete of the family Pseudonocardiaceae.

A novel actinomycete strain, designated KLBMP 1356T, was isolated from the root of halophyte Tamarix chinensis Lour. collected from the coastal area of Jiangsu province, PR China. The isolate was characterized using a polyphasic approach. Comparative analysis of the 16S rRNA gene sequence indicated that strain KLBMP 1356T was phylogenetically related to members of the family Pseudonocardiaceae and formed a distinct monophyletic clade between the genera Amycolatopsis (93.1-94.7 % 16S rRNA gene sequence similarity), Prauserella (93.6-95.1 %) and Saccharomonospora (93.2-94.3 %). The isolate displayed long spore chains containing rod-shaped and smooth-surfaced spores. Strain KLBMP 1356T contained meso-diaminopimelic acid as the diagnostic diamino acid, and galactose, arabinose and glucose as the whole-cell sugars. The major menaquinone was MK-9(H4) and the fatty acid profile was characterized by the predominance of iso-C16 : 0, C17 : 1ω8c, C17 : 1ω6c and C17 : 0. The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, unknown aminophospholipids and an unknown glycolipid. Mycolic acids were not present. The G+C content of the genomic DNA was 67.2 mol%. On the basis of the evidence from this polyphasic study, strain KLBMP 1356T is considered to represent a novel species of a new genus in the family Pseudonocardiaceae, for which the name Tamaricihabitans halophyticus gen. nov., sp. nov. is proposed. The type strain of the type species is KLBMP 1356T ( = DSM 45765T = NBRC 109361T).

Nocardia rhizosphaerae sp. nov., a novel actinomycete isolated from the coastal rhizosphere of Artemisia Linn., China.

A novel actinomycete, designated strain KLBMP S0043(T), was isolated from the rhizosphere soil of Artemisia Linn. collected from the coastal region of Lianyungang, Jiangsu Province, in east China and was studied in detail for its taxonomic position. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain KLBMP S0043(T) is a member of the genus Nocardia. The 16S rRNA gene sequence similarity indicated that strain KLBMP S0043(T) is closely related to Nocardia asteroides NBRC 15531(T) (97.61 %) and Nocardia neocaledoniensis SBHR OA6(T) (97.38 %); similarity to other type strains of the genus Nocardia was found to be less than 97.2 %. The organism has chemical and morphological features consistent with its classification in the genus Nocardia such as meso-diaminopimelic acid as the diagnostic diamino acid in the cell wall peptidoglycan and arabinose and galactose as the diagnostic sugars. The predominant menaquinone was identified as MK-8(H4ω-cycl). Mycolic acids were detected. The diagnostic phospholipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The predominant cellular fatty acids were identified as C16:0, C18:0, C18:1ω9c, 10-methyl C18:0 [tuberculostearic acid (TBSA)] and summed feature 3 (C16:1ω7c/C16:1ω6c). The G+C content of the genomic DNA was determined to be 71.4 mol%. The results of DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of the strain from its most closely related strains. Based on morphological, chemotaxonomic and phylogenetic data, strain KLBMP S0043(T) is considered to represent a novel species of the genus Nocardia, for which the name Nocardia rhizosphaerae sp. nov. is proposed. The type strain is KLBMP S0043(T) (=CGMCC 4.7204 (T) = KCTC 29678(T)).

Phylogenetic diversity and investigation of plant growth-promoting traits of actinobacteria in coastal salt marsh plant rhizospheres from Jiangsu, China.

Actinobacteria from special habitats are of interest due to their producing of bioactive compounds and diverse ecological functions. However, little is known of the diversity and functional traits of actinobacteria inhabiting coastal salt marsh soils. We assessed actinobacterial diversity from eight coastal salt marsh rhizosphere soils from Jiangsu Province, China, using culture-based and 16S rRNA gene high throughput sequencing (HTS) methods, in addition to evaluating their plant growth-promoting (PGP) traits of isolates. Actinobacterial sequences represented 2.8%-43.0% of rhizosphere bacterial communities, as determined by HTS technique. The actinobacteria community comprised 34 families and 79 genera. In addition, 196 actinobacterial isolates were obtained, of which 92 representative isolates were selected for further 16S rRNA gene sequencing and phylogenetic analysis. The 92 strains comprised seven suborders, 12 families, and 20 genera that included several potential novel species. All representative strains were tested for their ability of producing indole acetic acid (IAA), siderophores, 1-aminocyclopropane-1-carboxylate deaminase (ACCD), hydrolytic enzymes, and phosphate solubilization. Based on the presence of multiple PGP traits, two strains, Streptomyces sp. KLBMP S0051 and Micromonospora sp. KLBMP S0019 were selected for inoculation of wheat seeds grown under salt stress. Both strains promoted seed germination, and KLBMP S0019 significantly enhanced seedling growth under NaCl stress. Our study demonstrates that coastal salt marsh rhizosphere soils harbor a diverse reservoir of actinobacteria that are potential resources for the discovery of novel species and functions. Moreover, several of the isolates identified here are good candidates as PGP bacteria that may contribute to plant adaptions to saline soils.

Complete genome sequence of endophyte Bacillus flexus KLBMP 4941 reveals its plant growth promotion mechanism and genetic basis for salt tolerance.

Bacillus flexus KLBMP 4941 is a halotolerant endophyte isolated from the halophyte Limonium sinense. This strain can improve host seedling growth under salt stress conditions. We here report the complete genome information of endophyte KLBMP 4941. It has a circular chromosome and two plasmids for a total genome 4,104,242 bp in size with a G+C content of 38.09%. Genes related to plant growth promotion (PGP), such as those associated with nitrogen fixation, siderophore, spermidine, and acetoin synthesis were found in the KLBMP 4941 genome. Some genes responsible for high salinity tolerance, like genes associated with the Na+/H+ antiporter, glycine betaine transporter, and betaine-aldehyde dehydrogenase were also found in the KLBMP 4941 genome. The genome analysis will provide better understanding of the mechanisms underlying the promotion of plant growth in strain KLBMP 4941 under salt stress conditions and its ability to adapt to coastal salt marsh habitats, and provide a basis for its further biotechnological applications in agriculture.

Complete genome sequence of Kibdelosporangium phytohabitans KLBMP 1111(T), a plant growth promoting endophytic actinomycete isolated from oil-seed plant Jatropha curcas L.

Kibdelosporangium phytohabitans KLBMP 1111(T) is a plant growth promoting endophytic actinomycete isolated from the oil-seed plant Jatropha curcas L. collected from dry-hot valley, in Sichuan, China. The complete genome sequence of this actinomycete consists of one chromosome (11,759,770bp) with no plasmid. From the genome, we identified gene clusters responsible for polyketide and nonribosomal peptide synthesis of natural products, and genes related to the plant growth promoting, such as zeatin, 1-aminocyclopropane-1-carboxylate deaminase (ACCD) and siderophore. The complete genome information may be useful to understand the beneficial interactions between K. phytohabitans KLBMP 1111(T) and host plants.