A comprehensive comparative genomic analysis revealed that plant growth promoting traits are ubiquitous in strains of Stenotrophomonas.

Stenotrophomonas strains, which are often described as plant growth promoting (PGP) bacteria, are ubiquitous in many environments. A total of 213 genomes of strains of Stenotrophomonas were analyzed using comparative genomics to better understand the ecological roles of these bacteria in the environment. The pan-genome of the 213 strains of Stenotrophomonas consists of 27,186 gene families, including 710 core gene families, 11,039 unique genes and 15,437 accessory genes. Nearly all strains of Stenotrophomonas harbor the genes for GH3-family cellulose degradation and GH2- and GH31-family hemicellulose hydrolase, as well as intact glycolysis and tricarboxylic acid cycle pathways. These abilities suggest that the strains of this genus can easily obtain carbon and energy from the environment. The Stenotrophomonas strains can respond to oxidative stress by synthesizing catalase, superoxide dismutase, methionine sulfoxide reductase, and disulfide isomerase, as well as managing their osmotic balance by accumulating potassium and synthesizing compatible solutes, such as betaine, trehalose, glutamate, and proline. Each Stenotrophomonas strain also contains many genes for resistance to antibiotics and heavy metals. These genes that mediate stress tolerance increase the ability of Stenotrophomonas strains to survive in extreme environments. In addition, many functional genes related to attachment and plant colonization, growth promotion and biocontrol were identified. In detail, the genes associated with flagellar assembly, motility, chemotaxis and biofilm formation enable the strains of Stenotrophomonas to effectively colonize host plants. The presence of genes for phosphate-solubilization and siderophore production and the polyamine, indole-3-acetic acid, and cytokinin biosynthetic pathways confer the ability to promote plant growth. These strains can produce antimicrobial compounds, chitinases, lipases and proteases. Each Stenotrophomonas genome contained 1-9 prophages and 17-60 genomic islands, and the genes related to antibiotic and heavy metal resistance and the biosynthesis of polyamines, indole-3-acetic acid, and cytokinin may be acquired by horizontal gene transfer. This study demonstrates that strains of Stenotrophomonas are highly adaptable for different environments and have strong potential for use as plant growth-promoting bacteria.

Genomic and transcriptomic analyses provide new insights into the allelochemical degradation preference of a novel Acinetobacter strain.

A novel n-alkane- and phenolic acid-degrading Acinetobacter strain (designated C16S1T) was isolated from rhizosphere soil. The strain was identified as a novel species named Acinetobacter suaedae sp. nov. using a polyphasic taxonomic approach. Strain C16S1T showed preferential degradation of three compounds: p-hydroxybenzoate (PHBA) > ferulic acid (FA) > n-hexadecane. In a medium containing two or three of these allelochemicals, coexisting n-hexadecane and PHBA accelerated each other's degradation and that of FA. FA typically hindered the degradation of n-hexadecane but accelerated PHBA degradation. The upregulated expression of n-hexadecane- and PHBA-degrading genes induced, by their related substrates, was mutually enhanced by coexisting PHBA or n-hexadecane; in contrast, expression of both gene types was reduced by FA. Coexisting PHBA or n-hexadecane enhanced the upregulation of FA-degrading genes induced by FA. The expressions of degrading genes affected by coexisting chemicals coincided with the observed degradation efficiencies. Iron shortage limited the degradation efficiency of all three compounds and changed the degradation preference of Acinetobacter. The present study demonstrated that the biodegradability of the chemicals, the effects of coexisting chemicals on the expression of degrading genes and the strain's growth, the shortage of essential elements, and the toxicity of the chemicals were the four major factors affecting the removal rates of the coexisting allelochemicals.

Halomonas rhizosphaerae sp. nov. and Halomonas kalidii sp. nov., two novel moderate halophilic phenolic acid-degrading species isolated from saline soil.

Four vanillic acid-degrading bacterial strains, named LR5S13T, LR5S20, and M4R5S39T and LN1S58, were isolated from Kalidium cuspidatum rhizosphere and bulk soils, respectively. Phylogenetic analysis based on 16S rRNA gene as well as core genome revealed that LR5S13T and LR5S20 clustered closely with each other and with Halomonas ventosae Al12T, and that the two strains shared the highest similarities (both 99.3 %) with H. ventosae Al12T, in contrast, M4R5S39T and LN1S58 clustered together and with Halomonas heilongjiangensis 9-2T, and the two strains shared the highest similarities (99.4 and 99.2 %, respectively) with H. heilongjiangensis 9-2T. The average nucleotides identities based on BLAST (ANIb) and digital DNA-DNA hybridization (dDDH) values of strains LR5S13T to LR5S20, and M4R5S39T to LN1S58, were both higher than the threshold values for delineation of a species. The ANIb and dDDH values of the four strains to their closely relatives were lower than the threshold values. All four strains take phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol as the major polar lipids, Summed Feature 8, Summed Feature 3, and C16:0 as the major fatty acids. Based on the phylogenetic and phenotypic results, the four strains should be classified as two novel Halomonas species. Therefore, Halomonas rhizosphaerae sp. nov. (type strain LR5S13T = KCTC 8016T = CGMCC 1.62049T) and Halomonas kalidii (type strain M4R5S39T = KCTC 8015T = CGMCC 1.62047T) are proposed. The geographical distribution analysis based on 16S rRNA gene revealed that the two novel species are widely distributed across the globe, specifically in highly saline habits, especially in Central and Eastern Asia.

Aquibacillus rhizosphaerae sp. nov., an Indole Acetic Acid (IAA)-producing Halotolerant Bacterium Isolated from the Rhizosphere Soil of Kalidium cuspidatum.

A bacterium (named strain LR5S19T) was isolated from the rhizosphere soil of the halophyte Kalidium cuspidatum in Baotou, Inner Mongolia, China. Strain LR5S19T was Gram-stain-positive, motile with a polar flagellum, rod shaped, and spore forming at the terminal position in swollen sporangia, and it grew at 10-40 ℃ (optimum 30 ℃), pH 6.0-9.0 (optimum pH 7.0), and in the presence of 1.0-15.0% (w/v) NaCl (optimum 2.0%). The phylogenetic analysis of the 16S rRNA gene showed that strain LR5S19T shared the highest similarity (96.7%) with A. koreensis JCM 12387T, followed by A. kalidii HU2P27T (96.2%), A. sediminis BH258T (96.1%), and 'A. salsiterrae' 3ASR75-54T (96.0%). The ANIb, AAI and dDDH values between strain LR5S19T and its closely related type strains were 69.3-73.8%, 65.4-72.4% and 19.2-20.3%, respectively. The major polar lipids in strain LR5S19T consisted of diphosphatidylglycerol, phosphatidylglycerol, and three unidentified phospholipids, while MK-7 was the major respiratory quinone. The major fatty acids of the strain were anteiso-C15:0 and iso-C15:0. Based on phylogenomic and phenotypic results, strain LR5S19T should be classified as a novel species within the genus Aquibacillus, for which Aquibacillus rhizosphaerae sp. nov. is proposed. The type strain is LR5S19T (= CGMCC 1.62028T = KCTC 43434T). The comparative genomic analysis revealed that all eight members of Aquibacillus could utilize D-glucose via the glycolysis-gluconeogenesis pathway or the pentose phosphate pathway and use the tricarboxylic acid cycle as the metabolic center. The potassium ion transport proteins and compatible solute synthesis pathways in all the members likely also help them cope with hypersaline environments.

A comprehensive genomic analysis provides insights on the high environmental adaptability of Acinetobacter strains.

Acinetobacter is ubiquitous, and it has a high species diversity and a complex evolutionary pattern. To elucidate the mechanism of its high ability to adapt to various environment, 312 genomes of Acinetobacter strains were analyzed using the phylogenomic and comparative genomics methods. It was revealed that the Acinetobacter genus has an open pan-genome and strong genome plasticity. The pan-genome consists of 47,500 genes, with 818 shared by all the genomes of Acinetobacter, while 22,291 are unique genes. Although Acinetobacter strains do not have a complete glycolytic pathway to directly utilize glucose as carbon source, most of them harbored the n-alkane-degrading genes alkB/alkM (97.1% of tested strains) and almA (96.7% of tested strains), which were responsible for medium-and long-chain n-alkane terminal oxidation reaction, respectively. Most Acinetobacter strains also have catA (93.3% of tested strains) and benAB (92.0% of tested strains) genes that can degrade the aromatic compounds catechol and benzoic acid, respectively. These abilities enable the Acinetobacter strains to easily obtain carbon and energy sources from their environment for survival. The Acinetobacter strains can manage osmotic pressure by accumulating potassium and compatible solutes, including betaine, mannitol, trehalose, glutamic acid, and proline. They respond to oxidative stress by synthesizing superoxide dismutase, catalase, disulfide isomerase, and methionine sulfoxide reductase that repair the damage caused by reactive oxygen species. In addition, most Acinetobacter strains contain many efflux pump genes and resistance genes to manage antibiotic stress and can synthesize a variety of secondary metabolites, including arylpolyene, ß-lactone and siderophores among others, to adapt to their environment. These genes enable Acinetobacter strains to survive extreme stresses. The genome of each Acinetobacter strain contained different numbers of prophages (0-12) and genomic islands (GIs) (6-70), and genes related to antibiotic resistance were found in the GIs. The phylogenetic analysis revealed that the alkM and almA genes have a similar evolutionary position with the core genome, indicating that they may have been acquired by vertical gene transfer from their ancestor, while catA, benA, benB and the antibiotic resistance genes could have been acquired by horizontal gene transfer from the other organisms.

Idiomarina rhizosphaerae sp. nov. isolated from rhizosphere soil of Kalidium cuspidatum, and reclassification of Idiomarina andamanensis as Pseudidiomarina andamanensis comb. nov., and Idiomarina mangrovi as Pseudidiomarina mangrovi comb. nov.

A Gram-stain-negative, strictly aerobic, gliding motile, non-spore forming, rod-shaped indole-3-acetic acid producing bacterial strain, designated M1R2S28T, was isolated from the rhizosphere soil of Kalidium cuspidatum, in Tumd Right Banner, Inner Mongolia, China. Strain M1R2S28T grew at pH 5.0-10.0 (optimum 8.0), 10-45 °C (optimum 37 °C), in the presence of 0-20% (w/v) NaCl (optimum 5%). The phylogenetic trees based on the 16S rRNA gene sequences and the core-genome both revealed that strain M1R2S28T clustered tightly with Idiomarina loihiensis L2-TRT, and shared 99.3, 99.2, 98.7, and < 98.7% of the 16S rRNA gene sequence similarities with I. loihiensis L2-TRT, I. abyssalis KMM 227 T, I. ramblicola R22T, and all the other current type strains. The strain contained ubiquinone-8 (Q-8) as the sole respiratory quinone. Its major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified aminolipid, an unidentified phospholipid, and three unidentified lipids. Its major fatty acids were iso-C15:0, iso-C17:0, and iso-C17:1 ω9c. The genomic DNA G + C content was 46.8%. The average nucleotide identity based on BLAST (ANIb) and the digital DNA-DNA hybridization (dDDH) values of strain M1R2S28T to I. loihiensis L2-TRT, I. ramblicola R22T, and I. abyssalis KMM 227 T were 93.0, 82.9, and 81.8%, and 51.2, 26.0, and 25.0%, respectively. The phylogenetic and physiological results allowed the discrimination of strain M1R2S28T from its phylogenetic relatives. Idiomarina rhizosphaerae sp. nov. is, therefore, proposed with strain M1R2S28T (= CGMCC 1.19026 T = KCTC 92133 T) as the type strain. Additionally, based on the phylogenomic and genomic analysis results, Idiomarina andamanensis and Idiomarina mangrovi were transferred into genus Pseudidiomarina and be named Pseudidiomarina andamanensis comb. nov. and Pseudidiomarina mangrovi comb. nov., respectively.

Acuticoccus kalidii sp. nov., a 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing endophyte from a root of Kalidium cuspidatum.

A 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing, Gram-stain-negative, strictly aerobic, non-motile, yellow-reddish, oval-shaped bacterial strain, designated M5D2P5T, was isolated from a root of Kalidium cuspidatum, in Tumd Right Banner, Inner Mongolia, PR China. M5D2P5T grew at 10-40 °C (optimum 30-35 °C), pH 5.0-10.0 (optimum pH 8.0) and with 0-7% NaCl (optimum 3.0 %). The strain was positive for catalase and oxidase. The phylogenetic trees based on 16S rRNA gene sequences indicated that M5D2P5T clustered with Acuticoccus yangtzensis JL1095T, and shared 98.0, 97.3, 97.2, 96.9 and less than 96.9 % 16S rRNA gene similarities to A. yangtzensis JL1095T, Acuticoccus mangrovi B2012T, Acuticoccus sediminis PTG4-2T, Acuticoccus kandeliae J103T, and all the other type strains, respectively. However, the phylogenomic tree showed it clustered with A. kandeliae J103T. M5D2P5T contained Q-10 as the major respiratory quinone, as well as two minor respiratory quinones, Q-7 and Q-8. Its major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified phospholipid, an unidentified glycolipid, and four unidentified lipids. The genomic DNA G+C content was 66.5 %. The digital DNA-DNA hybridization score and the average nucleotide identity based on blast values of M5D2P5T to A. yangtzensis JL1095T, A. kandeliae J103T, A. mangrovi B2012T, and A. sediminis PTG4-2T, were 20.8, 23.7, 20.7, and 21.5 %, and 73.3, 79.5, 74.4, and 73.7 %, respectively. The phylogenetic and phenotypic characteristics allowed the discrimination of M5D2P5T from its phylogenetic relatives. The novel species Acuticoccus kalidii sp. nov. is therefore proposed, and the type strain is M5D2P5T (=CGMCC 1.19149T=KCTC 92132T).

Ignatzschineria rhizosphaerae sp. nov. Isolated from Rhizosphere Soil of the Halophyte Kalidium cuspidatum.

A Gram-staining negative, non-motile, aerobic, rod-shaped bacterium, designated strain HR5S32T, was isolated from rhizosphere soil of the halophyte Kalidium cuspidatum, in Tumd Right Banner, Inner Mongolia, northern China. Strain HR5S32T grew at 10-40 °C (optimum 30 °C), pH 6.0-10.0 (optimum pH 9.0), and 0-12% (w/v) NaCl (optimum 2%). It was positive for catalase, methyl red test, Voges-Proskauer test, and nitrate reduction, but negative to oxidase, urease and hydrolysis of Tween 80. The phylogenetic trees based on the 16S rRNA gene sequences and whole genome both showed that strain HR5S32T was most closely related to Ignatzschineria indica FFA1T (= KCTC 22643 T). Ubiquinone-8 (Q-8) was the major respiratory quinone. Phosphatidylglycerol, phosphatidylethanolamine, and phospholipid were the major polar lipids. Its major fatty acids were Summed features 8 (C18:1 ω6c and/or C18:1 ω7c), C16:0, Summed features 3 (C16:1ω6c and/or C16:1 ω7c), and C14:0. The genome consisted of a 3,074,733 bp circular chromosome, with a G + C content of 38.8%, predicting 2,763 coding sequence genes, 70 tRNA genes and 6 rRNA. The values of the average nucleotide identities (ANI) and digital DNA-DNA hybridization (dDDH) values of strain HR5S32T to I. indica FFA1T were 74.6% and 22.0%, respectively, hence significantly lower than the thresholds of 95% for ANI and 70% for DDH for species delineation. The results of phenotypic, physiological, genotypic, and phylogenetic tests allowed the differentiation of strain HR5S32T from its closely related species. Ignatzschineria rhizosphaerae sp. nov. is therefore proposed, and the type strain is HR5S32T (= CGMCC 1.19435 T = KCTC 92093 T).

Halomonas alkalisoli sp. nov., a novel haloalkalophilic species from saline-alkaline soil, and reclassification of Halomonas daqingensis Wu et al. 2008 as a later heterotypic synonym of Halomonas desiderata Berendes et al. 1996.

Two Gram-stain-negative, strictly aerobic, moderately halophilic, non-spore-forming and rod-shaped bacteria, designated M5N1S17T and M5N1S15, were isolated from saline soil in Baotou, China. A phylogenetic analysis based on 16S rRNA gene sequences showed that the two strains clustered closely with Halomonas montanilacus PYC7WT and shared 99.1 and 99.3% sequence similarities, respectively. The average nucleotide identity based on BLAST (ANIb) and MUMmer (ANIm) values of the two strains with each other were 95.5% and 96.7%, respectively, while the ANIb and ANIm values between the two strains and 15 closer Halomonas species were 74.8-91.3% and 84.1-92.6%, respectively. The major polar lipids of M5N1S17T are diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, and an unidentified phospholipid. The major polar lipids of M5N1S15 are diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, two unidentified phospholipids, and an unidentified lipid. The predominant ubiquinone in the two strains is Q-9. The major fatty acids of the two strains are C18:1ω6c and/or C18:1ω7c, C16:0, and C16:1ω7c and/or C16:1ω6c. Based on phylogenetic, phenotypic, and physiological results, strains M5N1S17T and M5N1S15 should be identified as a novel species of the genus Halomonas, for which Halomonas alkalisoli sp. nov. is proposed. The type strain is M5N1S17T (= CGMCC 1.19023T = KCTC 92130T). The phylogenetic trees showed that Halomonas daqingensis CGMCC 1.6443T clustered tightly with Halomonas desiderata FB2T, and the two strains shared >98.0% of ANI values with each other. Therefore, we propose the reclassification of H. daqingensis Wu et al. 2008 as a later heterotypic synonym of H. desiderata Berendes et al. 1996.

Sinomicrobium kalidii sp. nov., an indole-3-acetic acid-producing endophyte from a shoot of halophyte Kalidium cuspidatum.

To better understand the effects of endophytic bacteria on halophytes, a bacteria that produced indole-3-acetic acid and 1-aminocyclopropane-1-carboxylic acid deaminase, designated HD2P242T, was isolated from a shoot of Kalidium cuspidatum collected in Tumd Right Banner, Inner Mongolia, PR China. The cells of strain HD2P242T were Gram-stain-negative, strictly aerobic, motile by gliding, non-spore-forming and rod-shaped. Strain HD2P242T grew at pH 6.0-9.0 (optimum, pH 7.0) and 10-45 °C (optimum 37 °C), in the presence of 0-8 % (w/v) NaCl (optimum, 4 %). The strain was positive for oxidase and catalase. The phylogenetic trees based on the 16S rRNA gene sequences and the whole genome sequences both showed that strain HD2P242T clustered with Sinomicrobium pectinilyticum 5DNS001T and S. oceani SCSIO 03483T, and had 95.6, 94.3 and <94.3 % 16S rRNA gene similarities to S. pectinilyticum 5DNS001T, S. oceani SCSIO 03483T and all the other current type strains. Strain HD2P242T contained menaquinone 6 as its sole respiratory quinone. Its major polar lipids were phosphatidylethanolamine, two unidentified aminolipids, two unidentified phospholipids and an unidentified lipid. The major fatty acids were iso-C17 : 0, iso-C16 : 0 3-OH, anteiso-C17 : 0 and summed feature 6 (C19 : 1 ω9c and/or C19 : 1 ω11c). The genome consisted of a 5 364 211 bp circular chromosome, with a G+C content of 45.1 mol%, predicting 4391 coding sequence genes, 47 tRNA genes and two rRNA operons. The average nucleotide identity based on blast and the digital DNA-DNA hybridization values of strain HD2P242T with S. oceani SCSIO 03483T and S. pectinilyticum 5DNS001T were 73.8 and 77.0%, and 22.3 and 22.2%, respectively. The comparative genome analysis showed that the pan-genomes of strain HD2P242T and three Sinomicrobium type strains possessed 4236 clusters, whereas the core genome possessed 2162 clusters, which accounted for 52.3 % of all the clusters. The genomic analysis revealed that all four Sinomicrobium members could utilize d-glucose by the glycolysis-gluconeogenesis pathway or the pentose phosphate pathway. The tricarboxylic acid cycle was utilized as a metabolic centre. The phylogenetic, physiological and phenotypic characteristics allowed the discrimination of strain HD2P242T from its phylogenetic relatives. Therefore, Sinomicrobium kalidii sp. nov. is proposed, and the type strain is HD2P242T (=CGMCC 1.19025T=KCTC 92136T).

Corynebacterium kalidii sp. nov, an endophyte from a shoot of the halophyte Kalidium cuspidatum.

A Gram-stain-positive, non-motile, rod-shaped bacterial strain designated LD5P10T was isolated from a root of Kalidium cuspidatum, in Tumd Right Banner, Inner Mongolia, China. The strain grew at 4-40 â„ƒ (optimum 30 â„ƒ), and pH 5.0-10.0 (optimum pH 8.0), and in the presence of 0-16.0% (w/v) NaCl (optimum 2.0%). The strain was positive for catalase, and urease, and negative for nitrate reduction, and oxidase. The phylogenetic trees based on the 16S rRNA gene sequences and the whole genome sequence both revealed that strain LD5P10T clustered tightly with Corynebacterium glyciniphilum AJ 3170T and shared 98.1, 98.1, and < 98.1% of the 16S rRNA gene sequence similarities with strains C. glyciniphilum AJ 3170T, C. variabile DSM 20132T, and all the other current type strains. Strain LD5P10T contained MK-9 as the major respiratory quinone. Its major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphoglycolipid, two unidentified lipids, and two unidentified phospholipids. Its major fatty acids were C16:0 and C18:1 ω9c. The genomic DNA G + C content was 69.0%. The average nucleotide identity based on BLAST (ANIb), amino acid identity (AAI), and digital DNA-DNA hybridization (dDDH) values of strain LD5P10T to C. glyciniphilum AJ 3170T and C. variabile DSM 20132T were 82.9 and 76.4%, 85.3 and 69.4%, and 25.8 and 20.9%, respectively. The phylogenetic, physiological, and phenotypic results allowed the discrimination of strain LD5P10T from its phylogenetic relatives. Corynebacterium kalidii sp. nov. is, therefore, proposed with strain LD5P10T (= CGMCC 1.19144T = JCM 35048T) as the type strain.

Ruania suaedae sp. nov. and Ruania halotolerans sp. nov., two actinobacteria isolated from saline soil, and reclassification of Haloactinobacterium kanbiaonis as Occultella kanbiaonis comb. nov.

Two Gram-stain-positive, non-motile, strictly aerobic, yellow-coloured, rod-shaped bacterial strains, designated LR1S40T and M4N3S171T, were isolated from rhizosphere and bulk saline soil of Suaeda salsa collected in Inner Mongolia, China. Phylogenetic trees based on 16S rRNA gene and whole genome sequences showed that the two strains clustered tightly with strains of the genus Ruania. Strains LR1S40T and M4N3S171T had 95.5% 16S rRNA gene similarity to each other, and strain LR1S40T had 98.8, 98.7, 97.4 and <97.0% similarity to Ruania alkalisoli RN3S43T, Ruania rhizosphaerae LNNU 22110T, Ruania alba YIM 93306T and all other current type strains, while strain M4N3S171T had 98.6 and <97.0% similarity to R. alba YIM 93306T, and all other current type strains, respectively. The average nucleotide identity based on blast (ANIb) and digital DNA-DNA hybridization (dDDH) values of LR1S40T and M4N3S171T with each other and to the other type strains of Ruania were well below the threshold values (95% for ANIb, 70% for dDDH) for differentiating a species. Diphosphatidylglycerol and phosphatidylglycerol were the major polar lipids in both strains. The predominant menaquinone in both strains was both MK-8. The genome of strain LR1S40T consisted of a 3557440 bp circular chromosome, with a G+C content of 71.1 mol%, while the genome of strain M4N3S171T consisted of 4270413 bp, with a G+C content of 67.6 mol%. The phylogenetic, physiological and phenotypic characteristics allowed discrimination of the two strains from their relatives. The names Ruania suaedae sp. nov. [type strain LR1S40T (=CGMCC 1.19028T=KCTC 49726T)] and Ruania halotolerans sp. nov. [type strain M4N3S171T (=CGMCC 1. 19142T=KCTC 49727T)] are therefore proposed. During the publication of Haloactinobacterium kanbiaonis, Haloactinobacterium glacieicola (type strain T3246-1T), which was selected as the reference strain for the identification of H. kanbiaonis, was reclassified as Occultella glacieicola. The two phylogenetic trees showed that H. kanbiaonis HY164T tightly clustered with Occultella aeris F300T, and had the highest 16S rRNA gene similarity (99.8%) to O. aeris F300T. Based on the phylogenetic analysis and the publication record, Haloactinobacterium kanbiaonis should be reclassified as Occultella kanbiaonis comb. nov.

Description and characterization of three endophytic Bacillaceae from the halophyte Suaeda salsa: Paenalkalicoccus suaedae gen. nov., sp. nov., Cytobacillus suaedae sp. nov., and Bacillus suaedae sp. nov.

Three strains of members of the family Bacillaceae, which can inhibit the growth of some Gram-stain-positive strains, designated M4U3P1T, HD4P25T and RD4P76T, were isolated from Suaeda salsa halophytes in Baotou, Inner Mongolia, PR China. A phylogenetic analysis based on the 16S rRNA gene and the whole genome sequences revealed that HD4P25T clustered with Cytobacillus luteolus YIM 93174T with a similarity of 98.4 %, and RD4P76T shared the highest similarity of 16S rRNA gene with Bacillus mesophilus SA4T (97.5 %). M4U3P1T clustered with strains of genera Salipaludibacillus and Alkalicoccus based on whole-genome sequence analyses, but its 16S rRNA gene had the highest similarity to 'Evansella tamaricis' EGI 80668 (96.1 %). The average nucleotide's identity by blast (ANIb) and digital DNA-DNA hybridization (dDDH) values of the three isolated strains to their close relatives were well below the threshold value for identifying a novel species.On the basis of the phylogenetic, physiological and phenotypic results, Paenalkalicoccus suaedae gen. nov., sp. nov. [type strain M4U3P1T (=CGMCC 1.17076T=JCM 33851T)], Cytobacillus suaedae sp. nov. [type strain HD4P25T (=CGMCC 1.18651T =JCM 34524T)], and Bacillus suaedae sp. nov. [type strain RD4P76T (=CGMCC 1.18659T=JCM 34525T)] were proposed, respectively. All three species are ubiquitous in the bulk saline-alkaline soils, but only the species represented by strain RD4P76T was widely distributed in the rhizosphere soil, the above-ground part and the roots of S. salsa. The species represented by M4U3P1T can be detected in the roots of S. salsa, and rarely detected in the above-ground parts of S. salsa. The species represented by HD4P25T was rarely detected in the interior of S. salsa. The three strains could inhibit some of the Gram-stain-positive bacteria (i.e. members of the genera Planococcus, Zhihengliuella and Sanguibacter) in the saline-alkali soil. A genomic analysis of these three strains revealed that they can synthesize different antagonistic compounds, such as aminobenzoate and bacitracin or subtilisin.

Marinilactibacillus kalidii sp. nov., an Indole Acetic Acid-Producing Endophyte Isolated from a Shoot of Halophyte Kalidium cuspidatum.

A Gram-stain-positive, facultatively anaerobic, non-sporulating, motile with single polar flagellum, rod-shaped, indole-3-acetic acid (IAA)-producing bacterium, named M4U5P12T, was isolated from a shoot of Kalidium cuspidatum, Inner Mongolia, China. Strain M4U5P12T grew at pH 6.0-11.0 (optimum 7.5), 4-40 °C (optimum 25 °C), and in the presence of 0-15% (w/v) NaCl (optimum 4%). Positive for catalase, urease, methyl red (M.R.) reaction, and hydrolysis of starch; and negative for oxidase, Voges-Proskauer (V-P) test, and hydrolysis of cellulose. The phylogenetic trees based on the 16S rRNA gene sequences and the whole genome sequences both revealed that it clustered with Marinilactibacillus piezotolerans JCM 12337T (99.3%) and Marinilactibacillus psychrotolerans M13-2T (99.1%). The dDDH and ANIb values of strain M4U5P12T to M. piezotolerans DSM 16108T and M. psychrotolerans M13-2T were 19.3 and 18.9%, and 74.3 and 74.0%, respectively. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, and two unidentified lipids. The major fatty acids were C16:0, C18:1 ω9c, C16:1 ω9c, and C15:1 ω5c. The genomic DNA G + C content was 37.3%. On the basis of physiological, phenotypic, and phylogenetic characteristics, strain M4U5P12T should be classified as a novel species. Therefore, Marinilactibacillus kalidii sp. nov. is proposed, and the type strain is M4U5P12T (= CGMCC 1.17696T = KCTC 43247T).

Luteimonas saliphila sp. nov. and Luteimonas salinisoli sp. nov., two novel strains isolated from saline soils.

Two Gram-stain-negative, motile with single polar flagellum, rod-shaped bacterial strains, named SJ-9T and SJ-92T, were isolated from saline soils from Inner Mongolia, PR China. SJ-9T and SJ-92T grew at pH 6.5-10.0 and 7.0-11.0, 10-35 °C, and in the presence of 0-5 % and 0-8 % NaCl, respectively. Both strains were positive for oxidase, and negative for catalase. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that SJ-9T clustered with Luteimonas marina FR1330T (sharing 97.9 % 16S rRNA gene similarity), Luteimonas huabeiensis HB2T (96.5 %), 'Luteimonas wenzhouensis' YD-1 (96.6 %), and Luteimonas composti CC-YY255T (95.1 %), and shared low 16S rRNA gene similarities (<97.0 %) with all the other type strains; while SJ-92T clustered with Luteimonas aestuarii B9T (98.2 %), and shared low 16S rRNA gene similarities (<98.0 %) with all the other type strains. The two strains shared 97.4 % 16S rRNA gene similarity with each other. The major cellular fatty acids of both strains are iso-C15 : 0 and summed feature 9 (C16 : 0 10-methyl and/or iso-C17 : 1ω9c). The major polar lipids of both strains are diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The only respiratory quinone for both strains is ubiquinone-8 (Q-8). The genomic DNA G+C contents are 69.3 and 70.4 mol%, respectively. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity by blast (ANIb) values between the two strains were 22.6 and 77.5 %, while the values between SJ-9T and 'L. wenzhouensis' YD-1, L. marina FR1330T, and L. huabeiensis HB2T were 38.1, 39.2, and 21.9 %, and 82.5, 84.4, and 78.5 %, while those between SJ-92T and L. aestuarii B9T were 21.3 and 76.7 %. On the basis of the phenotypic, physiological and phylogenetic results, SJ-9T and SJ-92T represent two novel species of the genus Luteimonas, for which the names Luteimonas saliphila [type stain SJ-9T (=CGMCC 1.17377T=KCTC 82248T)] and Luteimonas salinisoli [type strain SJ-92T (=CGMCC 1.17695T=KCTC 82208T)] are proposed.

Gracilibacillus suaedae sp. nov., an indole acetic acid-producing endophyte isolated from a root of Suaeda salsa.

A Gram-stain-positive, facultatively anaerobic, spore-forming, motile with unipolar biflagella, rod-shaped, indole acetic acid-producing bacterium, named LD4P30T, was isolated from a root of Suaeda salsa collected in Inner Mongolia, northern China. Strain LD4P30T grew at pH 6.0-11.0 (optimum, pH 7.0), 10-40 °C (35 °C) and in the presence of 1-15% (w/v) NaCl (5%). The strain was positive for oxidase and negative for catalase. The major cellular fatty acids of strain LD4P30T were iso-C15:0, C15:1 ω5c and anteiso-C15:0; the major polar lipids were diphosphatidylglycerol and phosphatidylglycerol; and menaquinone-7 was the only respiratory quinone. The genomic DNA G+C content was 36.7 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain LD4P30T clustered with Gracilibacillus thailandensis TP2-8T, Gracilibacillus saliphilus YIM 91119T and Gracilibacillus lacisalsi BH312T, and showed 99.0, 98.9, 98.0 and <97.7% 16S rRNA gene similarity to G. thailandensis TP2-8T, G. saliphilus YIM 91119T, G. lacisalsi BH312T and all other current type strains, respectively. The digital DNA-DNA hybridization and average nucleotide identity based on blast values between strain LD4P30T and G. saliphilus YIM 91119T, G. thailandensis TP2-8T and G. lacisalsi BH312T were 44.9, 44.7 and 44.4%, and 91.1, 91.0 and 90.8%, respectively. Based on its phenotypic, physiological and phylogenetic characteristics, strain LD4P30T represents a novel species, for which the name Gracilibacillus suaedae is proposed. The type strain is LD4P30T (=CGMCC 1.17697T=KCTC 82375T).

Luteimonas deserti sp. nov., a novel strain isolated from desert soil.

A Gram-stain-negative, non-motile, rod-shaped bacterial strain, named SJ-16T, was isolated from desert soil collected in Inner Mongolia, northern PR China. Strain SJ-16T grew at pH 6.0-11.0 (optimum, pH 8.0-9.0), 4-40 °C (optimum, 30-35 °C) and in the presence of 0-8 % (w/v) NaCl (optimum, 0-2 %). The strain was negative for catalase and positive for oxidase. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain SJ-16T clustered with Luteimonas chenhongjianii 100111T and Luteimonas terrae THG-MD21T, and had 98.8, 98.6, 98.3 and <97.9 % of 16S rRNA gene sequence similarity to strains L. chenhongjianii 100111T, L. terrae THG-MD21T, L. aestuarii B9T and all other type strains of the genus Luteimonas, respectively. The major cellular fatty acids were iso-C15 : 0, iso-C16 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and summed feature 9 (C16 : 0 10-methyl and/or iso-C17 : 1 ω9c). Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were the major polar lipids, and ubiquinone-8 was the only respiratory quinone. The genomic DNA G+C content was 69.3 mol%. The digital DNA-DNA hybridization and average nucleotide identity values of strain SJ-16T to L. chenhongjianii 100111T, L. terrae THG-MD21T, L. rhizosphaerae 4-12T and L. aestuarii B9T were 36.9, 37.5, 24.0 and 21.1 %, and 80.9, 80.6, 80.7 and 76.3 %, respectively. Based on phenotypic, physiological and phylogenetic results, strain SJ-16T represents a novel species of the genus Luteimonas, for which the name Luteimonas deserti is proposed. The type strain is SJ-16T (=CGMCC 1.17694T=KCTC 82207T).