Plant-associated halotolerant bacteria improving growth of Vicia faba L. Mariout-2 under salinity conditions.

In this comprehensive investigation, we successfully isolated and characterized 40 distinct plant-associated halotolerant bacteria strains obtained from three halophytic plant species: Tamarix nilotica, Suaeda pruinosa, and Arthrocnemum macrostachyum. From this diverse pool of isolates, we meticulously selected five exceptional plant-associated halotolerant bacteria strains through a judiciously designed seed biopriming experiment and then identified molecularly. Bacillus amyloliquefaciens DW6 was isolated from A. macrostachyum. Three bacteria (Providencia rettgeri DW3, Bacillus licheniformis DW4, and Salinicoccus sesuvii DW5) were isolated for the first time from T. nilotica, S. pruinosa and S. pruinosa, respectively. Paenalcaligenes suwonensis DW7 was isolated for the first time from A. macrostachyum. These plant-associated halotolerant bacteria exhibited growth-promoting activities, including phosphate solubilization, nitrogen fixation, and production of bioactive compounds, i.e., ammonia, phytohormones, hydrogen cyanide, siderophores, and exopolysaccharides. A controlled laboratory experiment was conducted to reduce the detrimental impact of soil salinity. Vicia faba seedlings were inoculated individually or in mixtures by the five most effective plant-associated halotolerant bacteria to reduce the impact of salt stress and improve growth parameters. The growth parameters were significantly reduced due to the salinity stress in the control samples, compared to the experimental ones. The unprecedented novelty of our findings is underscored by the demonstrable efficacy of co-inoculation with these five distinct bacterial types as a pioneering bio-approach for countering the deleterious effects of soil salinity on plant growth. This study thus presents a remarkable contribution to the field of plant science and offers a promising avenue for sustainable agriculture in saline environments.

Characterization and bioremediation potential of nickel-resistant endophytic bacteria isolated from the wetland plant Tamarix chinensis.

Wetlands have been proposed as a sink for pollutants such as heavy metals. Wetland plants play a significant role in the phytoremediation of heavy metals. Here, we isolated and characterized three novel nickel (Ni)-resistant endophytic bacteria (NiEB) from the wetland plant Tamarix chinensis. The NiEB were identified as Stenotrophomonas sp. S20, Pseudomonas sp. P21 and Sphingobium sp. S42. All isolates tolerated 50 mg L-1 Ni, with isolates S20 and P21 being more tolerant to Ni at up to 400 mg L-1. Moreover, isolate S42 removed 33.7% of nickel sulfate from the water by forming white precipitates. The three isolates exhibited different plant growth-promoting (PGP) traits related to the production of indole acetic acid (IAA), siderophores and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. Phytotoxicity studies revealed that the growth of the wetland plants in a high Ni concentration (200 mg L-1) recovered after co-incubation with isolate S42. Overall, this study presents the first report of NiEB isolation from wetland plants and provides novel insights into the diverse functions of endophytic bacteria in a plant host with the potential to improve Ni phytoremediation.

Endophytic association of bioactive and halotolerant Humicola fuscoatra with halophytic plants, and its capability of producing anthraquinone and anthranol derivatives.

Halophytic plants growing in harsh desert environments are rich reservoirs of unique endophytic microorganisms. Here, healthy fresh plants of the families Tamaricaceae and Amarantaceae at three saline locations in Iran were investigated for their bioactive endophytic fungi. Among a vast number of isolates, eight isolates were identified as Humicola fuscoatra (Sordariomycetes, Pezizomycotina, Ascomycota) by microscopy and representative DNA sequences of the 5.8S rDNA (ITS) and partial ß-tubulin (TUB2). Those isolates were halotolerant, and highly bioactive, so that their intra- and extra-cellular metabolites possessed in vitro antifungal, antibacterial and antiproliferative activities, against a number of fungal and bacterial plant pathogens including the fungi Arthrobotrys conoides, Pyrenophora graminea, Pyricularia grisea and the bacteria Agrobacterium tumefaciens, Pseudomonas syringae and Xanthomonas oryzae. Chemical analyses of metabolites from the endophytes using HNMR, CNMR, NOESY, COSY, HMBC, HSQC, DEPT, TOCSY and EI MASS techniques identified 3,8-dihydroxy-1-methyl-9,10-anthracenedione (aloesaponarin II; an anthraquinone derivative), 1,8,9-anthracenetriol structure (chrysarobin; an anthranol derivative) and 2,4-di-tert-butylthiophenol in fungal extracts. To the best of our knowledge, this is the first report of endophytic association of halotolerant H. fuscoatra isolates with Tamaricaceae and Amarantaceae, and their bioactivity against plant pathogens. Also, the capability of chrysarobin and aloesaponarin II production is new to the fungal kingdom. These findings may find application in agriculture, pharmacology, and biotechnology.

Phytohalomonas tamaricis gen. nov., sp. nov., an endophytic bacterium isolated from Tamarix ramosissima roots growing in Kumtag desert.

A gram-stain-negative, aerobic, non-spore-forming, rod-shaped, non-motile bacterium strain R4HLG17T was isolated from Tamarix ramosissima roots growing in Kumtag desert. The strain grew at salinities of 0-16% (w/v) NaCl (optimum 5-6%), pH 5-9 (optimum 7) and at 16-45 °C. Based on 16S rRNA gene sequence similarity, strain R4HLG17T belonged to the family Halomonadaceae and was most closely related to Halomonas lutea DSM 23508T(95.1%), followed by Halotalea alkalilenta AW-7T(94.8%), Salinicola acroporae S4-41T(94.8%), Salinicola halophilus CG4.1T(94.6%), and Larsenimonas salina M1-18T(94.4%). Multilocus sequence analysis (MLSA) based on the partial sequences of 16S rRNA, atpA, gyrB, rpoD, and secA genes indicated that the strain R4HLG17T formed an independent and monophyletic branch related to other genera of Halomonadaceae, supporting its placement as a new genus in this family. The draft genome of strain R4HLG17T was 3.6 Mb with a total G + C content of 55.1%. The average nucleotide identity to Halomonas lutea DSM 23508T was 83.5%. Q-9 was detected as the major respiratory quinone and summed feature 8 (C18:1ω7c/C18:1ω6c), summed feature 3 (C16:1ω7c/C16:1ω6c), and C16:0 as predominant cellular fatty acids. On the basis of chemotaxonomic, phylogenetic, and phenotypic evidence, strain R4HLG17T is concluded to represent a novel species of a new genus within Halomonadaceae, for which the name Phytohalomonas tamaricis gen. nov., sp. nov., is proposed. The type strain is R4HLG17T (=ACCC 19929T=KCTC 52415T).

A coumarin analogue NFA from endophytic Aspergillus fumigatus improves drought resistance in rice as an antioxidant.

BACKGROUND: Drought and its resulting oxidative damage are the major yield limiting factors for crops in arid and semi-arid regions. Recent studies have found that endophytic fungi coexisting in plants can alleviate biotic or abiotic damage to plant growth and development. In order to screen for the endophytes associated with drought stress, 12 strains of endophytic fungi with high antioxidant activity isolated from riparian plants Myricaria laxiflora were evaluated for their effects in rice by the crude extracts. RESULTS: Of the 12 endophytic fungi, Aspergillus fumigatus SG-17 functioned most effectively, with the crude extract exhibiting relatively higher antioxidant capacity both in vivo and in vitro. The subsequent MS and NMR analysis showed that the primary substance responsible for the antioxidant activity in the extract was (Z)-N-(4-hydroxystyryl) formamide (NFA), an analogue of coumarin. Enzyme activity assay in nerve cells SH-SY5Y showed that NFA could maintain the membrane integrity and regulate the antioxidase activity under oxidative stress. In rice suffering drought stress, NFA effectively alleviated the harm by regulating the contents of NADPH oxidases, antioxidants and heat shock proteins, all of which are closely related with the reactive oxygen species pathway. CONCLUSION: These findings indicated that some endophytes from plants often subjected to flooding and oxidative stress could enhance drought resistance by producing compounds such as NFA to regulate the oxidative pathway.

Nakamurella deserti sp. nov., isolated from rhizosphere soil of Reaumuria in the Taklamakan desert.

A Gram-stain-positive, aerobic, non-motile, non-spore-forming, coccus-shaped actinobacterium, designated strain 12Sc4-1T, was isolated from a soil sample collected in the Taklamakan desert in Xinjiang Uygur Autonomous Region, China. Strain 12Sc4-1T grew at 8‒35 °C (optimum, 28‒30 °C), pH 6.0‒9.0 (optimum, pH 7.0) and in the presence of 0‒3 % (w/v) NaCl (optimum, 0 %). Phylogenetic analysis based on 16S rRNA gene sequence suggested that strain 12Sc4-1T belonged to the genus Nakamurella and shared the highest 16S rRNA gene sequence similarity to Nakamurella silvestris S20-107T (96.94 %). Strain 12Sc4-1T showed <96.0 % 16S rRNA gene sequence similarities to all other recognized members of the genus Nakamurella. Chemotaxonomic analyses showed that the isolate possessed meso-diaminopimelic acid as the diagnostic diamino acid of the peptidoglycan, glucose, mannose and galactose as whole-cell sugars, and MK-8(H4) as the predominant menaquinone. The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid, phosphatidylinositol, an unidentified phospholipid, an unidentified phosphoglycolipid and an unidentified glycolipid. The major fatty acids were C16 : 0 and anteiso-C15 : 0. The DNA G+C content was 72.1 mol% (draft genome sequence). On the basis of phylogenetic, phenotypic and chemotaxonomic analyses, strain 12Sc4-1T represents a novel species of the genus Nakamurella, for which the name Nakamurelladeserti sp. nov. is proposed. The type strain is 12Sc4-1T (=KCTC 49114T=CGMCC 1.16555T).

Bacillus tamaricis sp. nov., an alkaliphilic bacterium isolated from a Tamarix cone soil.

A Gram-stain-positive, alkaliphilic bacterium, designated EGI 80668T, was isolated from a Tamarix cone soil in Xinjiang, north-west China. Cells were facultatively anaerobic, terminal endospore-forming and motile by means of peritrichous flagella. Colonies were yellowish and the cells showed oxidase-negative and catalase-positive reactions. Strain EGI 80668T grew at pH 8.0-10.0 and with 0-10 % (w/v) NaCl (optimally at pH 9.0 and with 1-2 % NaCl) on marine agar 2216. The predominant menaquinone was MK-7. The major fatty acids were anteiso-C17 : 0 and anteiso-C15 : 0. The cellular polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, four unknown phospholipids and one unknown aminophospholipid. The G+C content of the genomic DNA was 38.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain EGI 80668T was affiliated to the genus Bacillus. The highest 16S rRNA gene sequence similarity between strain EGI 80668T and a member of the genus Bacillus was 96.83 % with Bacillus cellulosilyticus JCM 9156T. A polyphasic taxonomic study based on morphological, physiological, biochemical and phylogenetic data indicated that strain EGI 80668T represents a novel species of the genus Bacillus, for which the name Bacillus tamaricis sp. nov. (type strain EGI 80668T=KCTC 33703T=CGMCC 1.15917T) is proposed.

The Impacts of Soil Fertility and Salinity on Soil Nitrogen Dynamics Mediated by the Soil Microbial Community Beneath the Halophytic Shrub Tamarisk.

Nitrogen (N) is one of the most common limiting nutrients for primary production in terrestrial ecosystems. Soil microbes transform organic N into inorganic N, which is available to plants, but soil microbe activity in drylands is sometimes critically suppressed by environmental factors, such as low soil substrate availability or high salinity. Tamarisk (Tamarix spp.) is a halophytic shrub species that is widely distributed in the drylands of China; it produces litter enriched in nutrients and salts that are thought to increase soil fertility and salinity under its crown. To elucidate the effects of tamarisks on the soil microbial community, and thus N dynamics, by creating "islands of fertility" and "islands of salinity," we collected soil samples from under tamarisk crowns and adjacent barren areas at three habitats in the summer and fall. We analyzed soil physicochemical properties, inorganic N dynamics, and prokaryotic community abundance and composition. In soils sampled beneath tamarisks, the N mineralization rate was significantly higher, and the prokaryotic community structure was significantly different, from soils sampled in barren areas, irrespective of site and season. Tamarisks provided suitable nutrient conditions for one of the important decomposers in the area, Verrucomicrobia, by creating "islands of fertility," but provided unsuitable salinity conditions for other important decomposers, Flavobacteria, Gammaproteobacteria, and Deltaproteobacteria, by mitigating salt accumulation. However, the quantity of these decomposers tended to be higher beneath tamarisks, because they were relatively unaffected by the small salinity gradient created by the tamarisks, which may explain the higher N mineralization rate beneath tamarisks.

Pontibacter brevis sp. nov., isolated from rhizosphere soil of Tamarix ramosissima.

A Gram-stain-negative, oval-shaped and light pink pigmented bacterium, designated XAAS-2T, was isolated from rhizosphere soil of Tamarix ramosissima. The sole respiratory quinone of the type strain XAAS-2T was MK-7, and the principal cellular fatty acids were summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B) and iso-C15 : 0. The major polar lipids were phosphatidylethanolamine and two unidentified lipids. 16S rRNA gene sequence analysis indicated that strain XAAS-2T belonged to the genus Pontibacter within the family Cytophagaceae with sequence similarities of 93.9-97.1 % to other type species of the genus Pontibacter and to Pontibacter xinjiangensis CCTCC AB 207200T as the closest neighbour. The DNA G+C content of strain XAAS-2T was 50.6 mol%. The level of DNA-DNA relatedness of XAAS-2T and P. xinjiangensis CCTCC AB 207200T was 47.5 % (sd=3.27). Phenotypic and genotypic data suggested that strain XAAS-2T represents a novel species of the genus Pontibacter, for which the name Pontibacterbrevis sp. nov. is proposed, with the type strain XAAS-2T (=CCTCC AB 2016135T=JCM 31443T).

Salinicola tamaricis sp. nov., a heavy-metal-tolerant, endophytic bacterium isolated from the halophyte Tamarix chinensis Lour.

A Gram-stain-negative, rod-shaped bacterium, strain F01T, was isolated from leaves of Tamarix chinensis Lour. The isolate grew optimally at 30 °C, at pH 7.0 and with 5.0 % (w/v) NaCl, and showed a high tolerance to manganese, lead, nickel, ferrous ions and copper ions. The major fatty acids were C18 : 1ω7c and C16 : 0, and the predominant respiratory quinone was Q-9. Polar lipids were dominated by diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, unidentified aminoglycolipids and phospholipids. The DNA G+C content was 65.8 %. Based on multilocus phylogenetic analysis, strain F01T belonged to the genus Salinicola, with highest 16S rRNA gene sequence similarity to Salinicola peritrichatus CGMCC 1.12381T (97.7 %). The level of DNA-DNA hybridization between strain F01T and closely related Salinicola strains was well below 70 %. According to the phenotypic, genetic and chemotaxonomic data, strain F01T is considered to represent a novel species in the genus Salinicola, for which the name Salinicola tamaricis sp. nov. is proposed. The type strain is F01T (=CCTCC AB 2015304T=KCTC 42855T).

Alleviating salt stress in tomato seedlings using Arthrobacter and Bacillus megaterium isolated from the rhizosphere of wild plants grown on saline-alkaline lands.

Salt-induced soil degradation is common in farmlands and limits the growth and development of numerous crop plants in the world. In this study, we isolated salt-tolerant bacteria from the rhizosphere of Tamarix chinensis, Suaeda salsa and Zoysia sinica, which are common wild plants grown on a saline-alkaline land, to test these bacteria's efficiency in alleviating salt stress in tomato plants. We screened out seven strains (TF1-7) that are efficient in reducing salt stress in tomato seedlings. The sequence data of 16S rRNA genes showed that these strains belong to Arthrobacter and Bacillus megaterium. All strains could hydrolyze casein and solubilize phosphate, and showed at least one plant growth promotion (PGP)-related gene, indicating their potential in promoting plant growth. The Arthrobacter strains TF1 and TF7 and the Bacillus megaterium strain TF2 and TF3 could produce indole acetic acid under salt stress, further demonstrating their PGP potential. Tomato seed germination, seedling length, vigor index, and plant fresh and dry weight were enhanced by inoculation of Arthrobacter and B. megaterium strains under salt stress. Our results demonstrated that salt-tolerant bacteria isolated from the rhizosphere of wild plants grown on saline-alkaline lands could be used for alleviating salt stress in crop plants.

Metagenomic Signatures of Bacterial Adaptation to Life in the Phyllosphere of a Salt-Secreting Desert Tree.

UNLABELLED: The leaves of Tamarix aphylla, a globally distributed, salt-secreting desert tree, are dotted with alkaline droplets of high salinity. To successfully inhabit these organic carbon-rich droplets, bacteria need to be adapted to multiple stress factors, including high salinity, high alkalinity, high UV radiation, and periodic desiccation. To identify genes that are important for survival in this harsh habitat, microbial community DNA was extracted from the leaf surfaces of 10 Tamarix aphylla trees along a 350-km longitudinal gradient. Shotgun metagenomic sequencing, contig assembly, and binning yielded 17 genome bins, six of which were >80% complete. These genomic bins, representing three phyla (Proteobacteria,Bacteroidetes, and Firmicutes), were closely related to halophilic and alkaliphilic taxa isolated from aquatic and soil environments. Comparison of these genomic bins to the genomes of their closest relatives revealed functional traits characteristic of bacterial populations inhabiting the Tamarix phyllosphere, independent of their taxonomic affiliation. These functions, most notably light-sensing genes, are postulated to represent important adaptations toward colonization of this habitat. IMPORTANCE: Plant leaves are an extensive and diverse microbial habitat, forming the main interface between solar energy and the terrestrial biosphere. There are hundreds of thousands of plant species in the world, exhibiting a wide range of morphologies, leaf surface chemistries, and ecological ranges. In order to understand the core adaptations of microorganisms to this habitat, it is important to diversify the type of leaves that are studied. This study provides an analysis of the genomic content of the most abundant bacterial inhabitants of the globally distributed, salt-secreting desert tree Tamarix aphylla Draft genomes of these bacteria were assembled, using the culture-independent technique of assembly and binning of metagenomic data. Analysis of the genomes reveals traits that are important for survival in this habitat, most notably, light-sensing and light utilization genes.

Egibacter rhizosphaerae gen. nov., sp. nov., an obligately halophilic, facultatively alkaliphilic actinobacterium and proposal of Egibaceraceae fam. nov. and Egibacterales ord. nov.

A novel obligately halophilic, facultatively alkaliphilic actinobacterium, designated EGI 80759T, was isolated from the rhizosphere of Tamarix hispida Willd, Karamay, Xinjiang province, north-west China. Cells of strain EGI 80759T were Gram-stain-positive, non-motile and non-endospore-forming rods. Strain EGI 80759T showed obligately halophilic growth with a tolerance to 8-25 % (w/v) NaCl (optimum growth at 10-12 %, w/v) and facultatively alkaliphilic growth within the pH range 7.0-11.0 (optimum growth at pH 9.0-10.0). Cell-wall hydrolysates of the isolate contained meso-diaminopimelic acid (peptidoglycan type A1γ), with glucose, glucosamine, ribose and mannose as the major sugars. The major fatty acids identified were 10-methyl-C17 : 0, C17 : 1ω8c and C17 : 0. The predominant menaquinone was MK-9(H4). The G+C content of the genomic DNA was 72.1 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain EGI 80759T clustered with members of the class Nitriliruptoria and showed highest 16S rRNA gene sequence similarities with Euzebya tangerina F10T (90.3 %) and Nitriliruptor alkaliphilus ANL-iso2T (88.1 %). On the basis of the data obtained from phenotypic and chemotaxonomic studies and the phylogenetic analysis, the isolate is proposed to be a representative of a novel genus and a novel species, Egibacter rhizosphaerae gen. nov., sp. nov., of a proposed novel family, Egibacteraceae fam. nov., and order, Egibacterales ord. nov., within the class Nitriliruptoria. The type strain of the type species, Egibacter rhizosphaerae, is EGI 80759T ( = CGMCC 1.14997T = KCTC 39588T).

Effect of soil salinity and nutrient levels on the community structure of the root-associated bacteria of the facultative halophyte, Tamarix ramosissima, in southwestern United States.

Tamarix ramosissima is a tree species that is highly resistant to salt and drought. The Tamarix species survives in a broad range of environmental salt levels, and invades major river systems in southwestern United States. It may affect root-associated bacteria (RB) by increasing soil salts and nutrients. The effects of RB on host plants may vary even under saline conditions, and the relationship may be important for T. ramosissima. However, to the best of our knowledge, there have been no reports relating to T. ramosissima RB and its association with salinity and nutrient levels. In this study, we have examined this association and the effect of arbuscular mycorrhizal colonization of T. ramosissima on RB because a previous study has reported that colonization of arbuscular mycorrhizal fungi affected the rhizobacterial community (Marschner et al., 2001). T. ramosissima roots were collected from five locations with varying soil salinity and nutrient levels. RB community structures were examined by terminal restriction fragment (T-RF) length polymorphism, cloning, and sequencing analyses. The results suggest that RB richness, or the diversity of T. ramosissima, have significant negative relationships with electrical conductivity (EC), sodium concentration (Na), and the colonization of arbuscular mycorrhizal fungi, but have a significant positive relationship with phosphorus in the soil. However, at each T-RF level, positive correlations between the emergence of some T-RFs and EC or Na were observed. These results indicate that high salinity decreased the total number of RB species, but some saline-tolerant RB species multiplied with increasing salinity levels. The ordination scores of nonmetric multidimensional scale analysis of RB community composition show significant relationships with water content, calcium concentration, available phosphorus, and total nitrogen. These results indicate that the RB diversity and community composition of T. ramosissima are affected by soil salinity and nutrient levels. Sequence analysis detected one Bacteroidetes and eight Proteobacteria species. Most 16S rRNA gene sequences had high similarities with the bacteria isolated from saline conditions, indicating that at least a portion of the RB species observed in T. ramosissima was halotolerant.

Diversity of endophytic fungi of Myricaria laxiflora grown under pre- and post-flooding conditions.

Myricaria laxiflora is distributed along the riverbanks of the Yangtze River valley. The Three Gorges Dam has dramatically changed the habitat of M. laxiflora, which has evolved to develop increased resistance to flooding stress. In order to elucidate the relationship between plant endophytic fungi and flooding stress, we isolated and taxonomically characterized the endophytic fungi of M. laxiflora. One hundred and sixty-three fungi were isolated from healthy stems, leaves and roots of M. laxiflora grown under pre- and post-flooding conditions. Culture and isolation were carried out under aerobic and anaerobic conditions. Based on internal transcribed spacer sequence analysis and morphological characteristics, the isolates exhibited abundant biodiversity; they were classified into 5 subphyla, 7 classes, 12 orders, 17 families, and 26 genera. Dominant endophytes varied between pre- and post-flooding plants, among different plant tissues, and between aerobic and anaerobic culture conditions. Aspergillus and Alternaria accounted for more than 55% of all isolates. Although the number of isolates from post-flooding plants was greater, endophytes from pre-flooding plants were more diverse and abundant. Endophytes were distributed preferentially in particular tissues; this affinity was constrained by both the host habitat and the oxygen availability of the host.

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).

Impact of soil salinity on arbuscular mycorrhizal fungi biodiversity and microflora biomass associated with Tamarix articulata Vahll rhizosphere in arid and semi-arid Algerian areas.

Soil salinization is an increasingly important problem in many parts of the world, particularly under arid and semi-arid areas. Unfortunately, the knowledge about restoration of salt affected ecosystems using mycorrhizae is limited. The current study aims to investigate the impact of salinity on the microbial richness of the halophytic plant Tamarix articulata rhizosphere. Soil samples were collected from natural sites with increasing salinity (1.82-4.95 ds.m(-1)). Six arbuscular mycorrhizal fungi (AMF) species were isolated from the different saline soils and identified as Septoglomus constrictum, Funneliformis mosseae, Funneliformis geosporum, Funneliformis coronatum, Rhizophagus fasciculatus, and Gigaspora gigantea. The number of AMF spores increased with soil salinity. Total root colonization rate decreased from 65 to 16% but remained possible with soil salinity. Microbial biomass in T. articulata rhizosphere was affected by salinity. The phospholipid fatty acids (PLFA) C16:1ω5 as well as i15:0, a15:0, i16:0, i17:0, a17:0, cy17:0, C18:1ω7 and cy19:0 increased in high saline soils suggesting that AMF and bacterial biomasses increased with salinity. In contrast, ergosterol amount was negatively correlated with soil salinity indicating that ectomycorrhizal and saprotrophic fungal biomasses were reduced with salinity. Our findings highlight the adaptation of arbuscular and bacterial communities to natural soil salinity and thus the potential use of mycorrhizal T. articulata trees as an approach to restore moderately saline disturbed arid lands.

Prauserella endophytica sp. nov., an endophytic actinobacterium isolated from Tamarix taklamakanensis.

A novel endophytic actinobacterium, designated strain SP28S-3(T), was isolated from a surface-sterilized stem of Tamarix taklamakanensis collected from the southern edge of Taklamakan desert, Xinjiang, China. Strain SP28S-3(T) was found to show chemotaxonomic and morphological properties consistent with its classification in the genus Prauserella. The polar lipids were found to consist of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphoglycolipid, phosphatidylcholine, phosphatidylinositol, a glycolipid, an aminolipid and unidentified phospholipids. The major fatty acids (>10 %) were identified as iso-C16:0 and C16:0. The genomic DNA G+C content was determined to be 69.7 mol%. Phylogenetic analysis of strain SP28S-3(T) clearly showed that the strain had the highest similarity of 16S rRNA gene sequence with Prauserella coralliicola SCSIO 11529(T) (99.9 %), followed by Prauserella marina DSM 45268(T) (97.0 %) and is affiliated with the genus Prauserella. The low level (47.8 ± 5.5 %) of DNA-DNA relatedness between strain SP28S-3(T) and P. coralliicola SCSIO 11529(T) combined with other polyphasic taxonomic evidence clearly support the conclusion that strain SP28S-3(T) represents a novel Prauserella species, for which the name Prauserella endophytica sp. nov. is proposed. The type strain is SP28S-3(T) (=DSM 46655(T) = CGMCC 4.7182 (T)).

Allosalinactinospora lopnorensis gen. nov., sp. nov., a new member of the family Nocardiopsaceae isolated from soil.

A novel actinomycete, designated strain CA15-2(T), was isolated from a soil sample collected from the rhizosphere of tamarisk in the Lop Nor region, Xinjiang, China, and was characterized by using a polyphasic taxonomic approach. Optimal growth occurred at 37 °C and pH 7.5-8.0 and with 5% (w/v) NaCl. Strain CA15-2(T) formed white to pale-yellow branched substrate mycelium without fragmentation and sparse aerial mycelium with wavelike curves. Whole-cell hydrolysates of the isolate contained meso-diaminopimelic acid as the diagnostic diamino acid of the cell wall but no diagnostic sugars. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylmethylethanolamine, phosphatidylethanolamine, one unidentified glycolipid, one unidentified phospholipid and other unidentified lipids. MK-9(H8), MK-10(H8) and MK-10(H6) were the predominant menaquinones. The major fatty acids were iso-C16:0 and C16:0. The G+C content of the genomic DNA was 69.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CA15-2(T) formed a distinct subclade in the family Nocardiopsaceae, with less than 95% 16S rRNA gene sequence similarity to all known members of the family Nocardiopsaceae. On the basis of the evidence from our polyphasic study, a novel genus, Allosalinactinospora gen. nov., is proposed, with the type species Allosalinactinospora lopnorensis gen. nov., sp. nov. The type strain of Allosalinactinospora lopnorensis is strain CA15-2(T) ( = DSM 45697(T) =CGMCC 4.7074(T)).

Falsirhodobacter deserti sp. nov., isolated from sandy soil.

A Gram-stain-negative, non-motile, heterotrophic, rod-shaped bacterium, designated strain W402(T), was isolated from an enrichment culture of a Tamarix ramosissima rhizosphere soil sample from the Xinjiang desert in the PR China. Analysis of the almost-complete 16S rRNA gene sequence showed that the isolate was phylogenetically related to a species of the genus Falsirhodobacter, having a close relationship to Falsirhodobacter halotolerans JA744(T) (97 % similarity). However, DNA-DNA relatedness between W402(T) and F. halotolerans JA744(T) was 43.2±1.2 %. Strain W402(T) grew in 0-10 % (w/v) NaCl. The temperature and pH ranges for growth were 10-40 °C and pH 5.5-10.0, respectively. Optimal growth occurred at 1-3 % (w/v) NaCl, 30 °C and pH 7.0. The predominant cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c, 61.4 %), C18 : 0 (9.8 %) and 11-methyl C18 : 1ω7c (8.2 %). The major quinone of strain W402(T) was Q-10. Phosphatidylethanolamine was predominant in the polar lipid profile. The DNA G+C content of strain W402(T) was 67.3 mol%. Taken together, these results confirm that W402(T) represents a novel species of the genus Falsirhodobacter, for which the name Falsirhodobacter deserti sp. nov. is proposed. The type strain is W402(T) ( = ACCC 05851(T) = KCTC 32408(T)).