Soil In Yunnan Research Articles

Characterization and Health Risk of Heavy Metals in PM2.5 from Road Fugitive Dust in Five Cities of Yunnan Province

In order to study the contents, sources, and health risk of PM2.5 in road fugitive dust in Yunnan, road fugitive dust samples were collected from five typical cities including Kunming, Baoshan, Wenshan, Zhaotong, and Yuxi. Particulate matter resuspension technology was used to levitate the dust samples and collect PM2.5. Eight heavy metals including chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), selenium (As), cadmium (Cd), and lead (Pb) in PM2.5 were detected using ICP-MS. The results showed that the contents of Cr, Ni, Cu, Zn, and Pb in road fugitive dust seriously exceeded the background values of Yunnan soil. The enrichment factors showed that most of the heavy metals in PM2.5 of road fugitive dust in the five cities of Yunnan were moderately enriched and strongly enriched, which were greatly influenced by human activities. The results of correlation analysis and principal component analysis showed that the heavy metals in PM2.5 of road fugitive dust in Yunnan were all affected by soil and traffic sources. The other sources varied greatly in different cities:Kunming was affected by iron and steel melting sources, Baoshan and Yuxi were affected by non-ferrous metal smelting sources, and Zhaotong was affected by coal sources. Health risk analysis showed that Cr, Pb, and As in road fugitive dust PM2.5 had non-carcinogenic risk in children in Kunming, Yuxi, and Zhaotong, respectively, and Cr in Kunming also had a lifetime carcinogenic risk.

Ralstonia wenshanensis sp. nov., a novel bacterium isolated from a tobacco field in Yunnan, China.

A Gram-negative, aerobic, motile with paired polar flagella and rod-shaped bacterium strain (56D2T) was isolated from tobacco planting soil in Yunnan, PR China. Major fatty acids were C16 : 1 ω7c (summed feature 3), C16 : 0 and C18 : 1 ω7c (summed feature 8). The polar lipid profile of strain 56D2T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid and one unidentified glycolipid. Moreover, strain 56D2T contained ubiquinone Q-8 as the sole respiratory quinone. 16S rRNA gene sequence analysis showed that strain 56D2T was closely related to members of the genus Ralstonia and the two type strains with the highest sequence identities were R. mannitolilytica LMG 6866T (98.36 %) and R. pickettii K-288T (98.22 %). The 16S rRNA gene sequence identities between strain 56D2T and other members of the genus Ralstonia were below 98.00 %. Genome sequencing revealed a genome size of 5.87 Mb and a G+C content of 63.7 mol%. The average nucleotide identity values between strain 56D2T and R. pickettii K-288T, R. mannitolilytica LMG 6866 T and R. insidiosa CCUG 46789T were less than 95 %, and the in silico DNA-DNA hybridization values (yielded by formula 2) were less than 70 %. Based on these data, we conclude that strain 56D2T represents a novel species of the genus Ralstonia, for which the name Ralstonia wenshanensis sp. nov. is proposed. The type strain of Ralstonia wenshanensis sp. nov. is 56D2T (=CCTCC AB 2021466T=GDMCC 1.2886T=JCM 35178T).

Insights into the mechanism of the effects of rhizosphere microorganisms on the quality of authentic Angelica sinensis under different soil microenvironments

BackgroundAngelica sinensis (Oliv.) Diels (A. sinensis) is a Chinese herb grown in different geographical locations. It contains numerous active components with therapeutic value. Rhizosphere microbiomes affect various aspects of plant performance, such as nutrient acquisition, growth and development and plant diseases resistance. So far, few studies have investigated how the microbiome effects level of active components of A. sinensis. This study investigated whether changes in rhizosphere microbial communities and metabolites of A. sinensis vary with the soil microenvironment. Soils from the two main A. sinensis-producing areas, Gansu and Yunnan Province, were used to conduct pot experiments. The soil samples were divided into two parts, one part was sterilized and the other was unsterilized planting with the seedling variety of Gansu danggui 90–01. All seedlings were allowed to grow for 180 days. At the end of the experiment, radix A. sinensis were collected and used to characterize growth targets and chemical compositions. Rhizosphere soils were subjected to microbial analyses.ResultsChanges in metabolic profiles and rhizosphere microbial communities of A. sinensis grown under different soil microenvironments were similar. The GN (Gansu non-sterilized), YN (Yunnan non-sterilized), GS (Gansu sterilized), and YS (Yunnan sterilized) groups were significantly separated. Notably, antagonistic bacteria such as Sphingomonas, Pseudomonas, Lysobacter, Pseudoxanthomonas, etc. were significantly (p < 0.05) enriched in Gansu soil compared with Yunnan soil. Moreover, senkyunolide I and ligustilide dimers which were enriched in GS group were strongly positively correlated with Pseudomonas parafulva; organic acids (including chlorogenic acid, dicaffeoylquinic acid and 5-feruloylquinic acid) and their ester coniferyl ferulate which were enriched in YS Group were positively associated with Gemmatimonadetes bacterium WY71 and Mucilaginibater sp., respectively.ConclusionsThe soil microenvironment influences growth and level/type of active components in A. sinensis. Further studies should explore the functional features of quality-related bacteria, identify the key response genes and clarify the interactions between genes and soil environments. This will reveal the mechanisms that determine the quality formation of genuine A. sinensis.

Screening of Phosphate-Solubilizing Fungi From Air and Soil in Yunnan, China: Four Novel Species in Aspergillus, Gongronella, Penicillium, and Talaromyces.

Phosphate-solubilizing fungi (PSF) play an important role in increasing the bioavailability of phosphorus in soils for plants. Thirteen fungal strains, one collected from air and 12 from soil, were screened and described here in detail. These fungal strains were tested for their ability to solubilize tricalcium phosphate (TCP) on both solid and liquid Pikovskaya (PVK) media in vitro. The airborne fungal strain KUMCC 18-0196 (Aspergillus hydei sp. nov.) showed the most significant phosphate solubilizing activity on a solid PVK medium with the solubilization index (SI) (2.58 ± 0.04 cm) and the highest solubilized phosphates (1523.33 ± 47.87 μg/mL) on a liquid PVK medium. To the best of our knowledge, A. hydei sp. nov. is the first phosphate-solubilizing fungus reported from air. We also provide the identification especially for Aspergillus, Penicillium and Talaromyces, generally reported as PSF. It is important to not only screen for PSF but also identify species properly so that researchers have a clearer taxonomic picture for identifying potential taxa for future plant growth-promoting applications. Herein, A. hydei (section Nigri), Gongronella hydei, Penicillium soli (section Lanata-Divaricata) and Talaromyces yunnanensis (section Talaromyces) are fully described and introduced as new to science. These four new species are identified based on both morphological characteristics and multigene phylogenetic analyses, including the genealogical concordance phylogenetic species recognition method where necessary. Penicillium austrosinense is considered to be a synonym of P. guaibinense.

Combined Cultivation Pattern Reduces Soil Erosion and Nutrient Loss from Sloping Farmland on Red Soil in Southwestern China

Crops are usually planted on sloping land in mountainous areas due to limited suitable land area. This results in serious soil erosion and loss of nitrogen (N) and phosphorus (P) to land degradation and water eutrophication. It is important to adopt appropriate cultivation practices to change this situation. However, few long-term in situ measurements are available to assess the magnitude of effects of combined cultivation patterns on soil erosion and nutrient loss from sloping farmland with red soil, as well to quantify N and P losses through runoff and sediment transport. A field trial with the cash crop (CC) Nicotiana tabacum was carried out under natural rainfall conditions on sloping farmland with red soil in Yunnan, China during 2014–2017. Four cultivation patterns were applied. They included NVF (No fertilizer application + Vertical ridge + Film covered), OVF (Optimizing fertilizer application + Vertical ridge + Film covered), OHF (Optimizing fertilizer application + Horizontal ridge + Film covered), and OHFR (Optimizing fertilizer application + Horizontal ridge + Film removed). The first two treatments belonged to the vertical ridge (VR) group, and the remaining treatments belonged to the horizontal ridge (HR) group. Results indicated the HR group performed significantly better than the VR group, especially the OHFR treatment, in terms of the HR group producing average runoff (177.12–182.27 mm), sediment loss (2673.33–3309.17 kg·ha−1), and nutrient loss of total nitrogen (TN) (7.58–7.93 kg·ha−1), total phosphorus (TP) (1.00–1.09 kg·ha−1) through runoff, TN (3.53–4.72 kg·ha−1), TP (2.59–2.76 kg·ha−1) through sediment. TN was lost mainly through runoff transport, while TP was lost mainly through sediment transport. On average, the HR group decreased runoff, sediment, total N and P loss by 39% to 73% relative to the OVF treatment, whereas NVF treatment increased 3% to 30% of those (p &lt; 0.05). Under four cultivation patterns, total dissolved nitrogen (TDN) was the dominant form, which accounted for 71–77% of TN. The average percentage of NO3−-N/TN was about 45–52%, much higher than NH4+-N/TN of around 8–10% in runoff. Total dissolved phosphorus (TDP) made up about 48–59% of TP in runoff. Redundancy analysis (RDA) showed that sediment, runoff, and soil pH were the three key factors controlling nutrient loss. In conclusion, OHFR is recommended because it consistently outperformed other patterns in terms of reducing runoff, sediment, and nutrient losses.

Contents and Health Risk Assessment of Elements in Three Edible Ectomycorrhizal Fungi (Boletaceae) from Polymetallic Soils in Yunnan Province, SW China.

Ectomycorrhizal fungi (EcMF) can mobilize mineral elements directly from insoluble mineral sources and accumulate various metallic elements and metalloids from soils to their fruiting bodies. Mushrooms from genus Boletus and its related genus are one of the most important EcMF which are consumed worldwide as wild edible mushrooms. Yunnan province (China) is a high biodiversity of genus Boletus mushrooms but is also an area with potential elevated contents of toxic elements in soil. Total contents of As, Ag, Ba, Cd, Co, Cr, Cs, Cu, Li, Mn, Ni, Pb, Rb, Sb, Sr, Tl, U, V, and Zn in three edible EcMF species collected from five sites of Yunnan were analyzed by inductively coupled plasma mass spectrometer. The highest contents for As, Cd, and Pb were 7.8mgkg-1 dry weight (dw) in the caps of Butyriboletus roseoflavus, 3.4mgkg-1 dw in the caps of B. roseoflavus, and 6.4mgkg-1 dw in the stipes of Hemileccinum impolitum. Health risk assessment of As, Cd, and Pb indicated that the estimated exposure due to intakes of some mushroom samples from the sites were above the limits recommended by the Joint FAO/WHO Expert Committee on Food Additives. Since EcMF were considered as bioexclusors of Cr, higher Cr contents in the mushroom samples, compared with previous studies, indicated high geochemical background value of Cr in the sampling sites. Relatively higher V contents in mushrooms from family Boletaceae could also associate with the high V contents in Yunnan soil. Further work is needed to identify the places in Yunnan with geochemical anomalies resulting in high levels of toxic elements in EcMF.

Risk Assessment and Source Identification of Toxic Metals in the Agricultural Soil around a Pb/Zn Mining and Smelting Area in Southwest China.

Mining and smelting activities are the primary sources of toxic metal pollution in China. The purpose of this study was to investigate the pollution risk and identify sources of metals in the arable soil of a Zn/Pb mining and smelting district located in Huize, in Southwest China. Topsoil (346) and profile (three) samples were collected and analyzed to determine the total concentrations of eight toxic elements (Cd, Hg, As, Pb, Cr, Cu, Zn and Ni). The results showed that the mean Cd, Hg, As, Pb, Cr, Cu, Zn and Ni concentrations were 9.07, 0.37, 25.0, 512, 88.7, 239, 1761 and 90.3 mg/kg, respectively, all of which exceeded both the Huize and Yunnan soil background levels. Overall the topsoil was quite acidic, with a mean pH of 5.51. The mean geoaccumulation index (Igeo) revealed that the pollution level was in the order of Pb > Zn > Cd > Hg > As > Ni > Cu > Cr. The ecological risk index (Ei) indicated that there were serious contamination risks for Cd and Hg, high risk for Pb, moderate risk for As, and Cd and Hg were the dominant contributors to the high combined ecological risk index (Er) with a mean parameter of 699 meaning a serious ecological risk. The Nemerow pollution index (Pn) showed that 99.1% of soil samples were highly polluted or worse. Horizontally, high concentrations of Cd, Hg, As, Pb and Zn appeared in the north and middle of the study area, while Cr, Cu and Ni showed an opposite trend. Vertically, as the depth increased, Cd, Hg, As, Pb and Zn contents declined, but Cr, Cu and Ni exhibited an increasing trend. The mobilities of the metals were in the order of Zn > Cd > Hg > As > Pb. Horizontal and vertical distribution, coupled with correlation analysis, PCA and CA suggested that Cd, Hg, As, Pb and Zn mainly came from the anthropogenic sources, whereas Cr and Ni had a lithogenic origin. The source of Cu was a combination of the presence of parent materials as well as human activities. This study provides a base for the local government to control the toxic metal pollution and restore the soil environment system and an effective method to identify the sources of the studied pollutants.

Principal Component Analysis and Ecological Risk Assessment of Heavy Metals in Farmland Soils around a Pb-Zn Mine in Southwestern China

The farmland soil around a Pb-Zn mine in southwestern China was studied. One hundred forty-nine surface soil samples were taken from 0-20 cm depth, and the contents of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were tested. The correlations among these heavy metals were studied with multivariate analysis, and the potential sources of the metals were identified. The environmental risk of the metals was evaluated with the Potential Ecological Risk Index method. The results showed that the amounts of Cd, Pb, and Zn were at relatively high level, with average concentrations of 15.56, 419.4, and 933.4mg·kg-1 respectively, indicating the soil was heavily polluted. The average concentrations of Hg and As were 0.13 and 37.3mg·kg-1, suggesting moderate soil pollution. The average concentrations of Cu, Ni, and Cr were lower than Yunnan soil background values. The multivariate analysis suggested that the sources of Cd, Pb, Zn, Hg, and As were similar and came mainly from smelting activities in the mining area. The sources of Cu, Ni, and Cr were similar and can be attributed to natural sources. The comprehensive potential ecological risk index was 2294.8, which suggested a high potential ecological risk. In general, the farmland soils in the research area were polluted seriously by the mining and industrial activities.

Concentration and Distribution of Fe, Al, Mn and Cr in Soils

The concentration and distribution of metal (Fe, Al, Mn and Cr) elements in agricultural and non-agricultural soils were investigated in upstream of the Pearl River, China. The result showed that total Fe, Al and Cr concentrations in agricultural soils were higher than those in non-agricultural soils, while total Mn concentrations in agricultural soils were lower than those in non-agricultural soils, indicating that agricultural input, such as water irrigation, fertilizer and pesticide application, may have led to the accumulation of Fe, Al and Cr in agricultural soils. Total concentrations of the metal elements in agricultural and non-agricultural soils were compared with the background values of Yunnan soil, the result showed Fe, Al, Mn and Cr were lower in both agricultural and non-agricultural soils in the study area.

Concentration and Distribution of Metal Elements in Soils near a Upstream of the Pearl River, China

The concentration and distribution of metal (Mg, K, Ca and Na) elements in agricultural and non-agricultural soils were investigated in upstream of the Pearl River, China. The result showed that total Mg, K, Ca and Na concentrations in agricultural soils were higher than those in non-agricultural soils, indicating that agricultural input, such as water irrigation, fertilizer and pesticide application, may have led to the accumulation of Mg, K, Ca and Na in agricultural soils. Total concentrations of the metal elements in agricultural and non-agricultural soils were compared with the background values of Yunnan soil, the result showed Mg, K and Na were lower in both agricultural and non-agricultural soils in the study area, while Ca was relatively higher, which were possibly due to Karsts geographic environment in the study area.

Relationships between vegetation and stomata, and between vegetation and pollen surface soil in Yunnan, Southwest China

Surface pollen and stomata of 61 samples collected in a study area ranging from tropical seasonal rainforest to oak forest (Quercus spinosa) in the Yulong Snow Mountain region in Yunnan, China, are used to distinguish vegetation communities. The results show that tropical seasonal rainforest (and mountain rainforest), south subtropical evergreen broad-leaved forest, and Quercus shrub are distinguished effectively from other vegetation types by analysis of surface pollen. The south subtropical evergreen broad-leaved forest, Pinus kesiya forest and evergreen broadleaf forest are distinguished effectively from other types of vegetation by pollen analysis. However, P. yunnanensis forest is not distinguished from other vegetation types, and P. armandii, P. densata forest and temperate deciduous conifer mixed forest are not distinguished. The over-representation of Pinus pollen is the main reason that these vegetation communities are not distinguished from each other. Conifer stomata analysis is an effective tool for identifying and distinguishing different types of coniferous forest, and this method performs well even with a small number of sampling points.

The Research of Soil and Natural Colonized Plants in Lead-Zinc Tailings of Huize

In order to select adaptable plants in lead-zinc tailings of Huize, tailings soil and natural colonized plants on tailings were researched. The results showed that Cd polluted badly soil, the content of Cd in lead-zinc tailings soil of Huize was 515.19 times of natural soil in Yunnan; Pb and Zn were major factor of pollution in tailings, the content of Pb and Zn in lead-zinc tailings soil were 120.92 and 78.44 times of natural soil in Yunnan. The heavy metal content have decreased with prolonging accumulation time, and the heavy metal content of tailings edge is significantly lower than the center. There were a lot of natural colonized species on lead-zinc tailings of Huize, ten species were dominant. The ten species were far way from critical levels for hyper accumulator, but could grow under heavy metals stress and have a high tolerance to Pb and Zn, so can be considered as pioneer plants of revegetation in lead-zinc tailings of Huize.

Kineococcus glutineturens sp. nov., isolated from soil in Yunnan, south-west China

An orange-coloured, non-spore-forming, motile and coccus-shaped actinobacterium, designated YIM 75677(T), was isolated from a soil sample collected from a dry-hot river valley in Dongchuan county, Yunnan Province, south-west China and its taxonomic position was investigated. Growth of strain YIM 75677(T) occurred at 12-55 °C, pH 6.0-9.0 and NaCl tolerance up to 2 % (w/v). Cells adhered to agar media and were agglutinated tightly together. The peptidoglycan contained meso-diaminopimelic acid, alanine and glutamic acid. The whole-cell hydrolysates mainly contained glucose, galactose, mannose and ribose. The predominant menaquinone was MK-9 (H(2)) and the major fatty acids were anteiso-C(15:0) and iso-C(15:0). Mycolic acids were not present. The DNA G+C content of strain YIM 75677(T) was 74.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequence comparisons clearly revealed that strain YIM 75677(T) represents a novel member of the genus Kineococcus and is closely related to Kineococcus xinjiangensis S2-20(T) (level of similarity, 98.6 %). Meanwhile, the result of DNA-DNA hybridization between strain YIM 75677(T) and K. xinjiangensis S2-20(T) demonstrated that this isolate represented a different genomic species in the genus Kineococcus. On the basis of phylogenetic, phenotypic and chemotaxonomic characteristics, strain YIM 75677(T) represents a novel species of the genus Kineococcus, for which the name Kineococcus glutineturens sp. nov. is proposed. The type strain is YIM 75677(T) (=CCTCC AA 209075(T) = JCM 18126(T)).

Pseudonocardia yuanmoensis sp. nov., a novel actinobacterium isolated from soil in Yunnan, south-west China

A novel Gram-stain positive, aerobic, non-motile, spore-forming actinobacterium, designated YIM 75926(T), was isolated from a soil sample collected at soil forest in Yuanmo county of Yunnan province, south-west China. Its taxonomic position was investigated by a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that the novel strain YIM 75926(T) belongs to the genus Pseudonocardia and was closely related to Pseudonocardia halophobica DSM 43089(T) (98.1% similarity). Strain YIM 75926(T) had MK-8 (H(4)) as the predominant menaquinone. The whole organism hydrolysates mainly consisted of meso-diaminopimelic acid, mannose, glucose, galactose and arabinose. The major cellular fatty acids were iso-C(16:0) (37.16%) and C(16:0) (12.43%). The DNA G+C content of strain YIM 75926(T) was 70.6mol%. The resultant phylogenetic trees further showed that strain YIM 75926(T) belong to Pseudonocardia and had a distinct subclade within the evolutionary radiation of the genus Pseudonocardia. On the basis of its comparative analysis of phenotypic and genotypic characteristics, it is proposed that strain YIM 75926(T) represent a novel species of the genus Pseudonocardia, named Pseudonocardia yuanmoensis sp. nov. The type strain is YIM 75926(T) (=CCTCC AA 2011017(T) =JCM 18055(T)).

Actinomadura alba sp. nov., isolated from soil in Yunnan, China

A novel actinomycete, strain YIM 45681(T), which was isolated from soil in a suburb of Kunming, Yunnan Province, China, was subjected to phenotypic and genotypic characterization. The micro-organism, which produces short spore chains arranged in spirals on the aerial mycelium, was shown to have meso-diaminopimelic acid in the cell wall. The sugars present in whole-cell hydrolysates were ribose, xylose, galactose, madurose and glucose. The predominant menaquinones were MK-9(H(4)), MK-9(H(6)) and MK-9(H(2)). The phospholipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. The major fatty acids were iso-C(16 : 1) H, C(17 : 1) omega 8c, 10-methyl C(17 : 0) and C(16 : 0). A comparative analysis of 16S rRNA gene sequences indicated that the organism formed a distinct clade within the evolutionary radiation of the family Thermomonosporaceae, and that it was closely associated with members of the genus Actinomadura. A broad range of phenotypic and genetic data supported the suggestion that this organism represents a novel species of the genus Actinomadura, for which the name Actinomadura alba sp. nov. is proposed, with YIM 45681(T) (=DSM 45045(T) =CCTCC AA206005(T)) as the type strain.

Georgenia ruanii sp. nov., a novel actinobacterium isolated from forest soil in Yunnan (China), and emended description of the genus Georgenia

A Gram-positive, motile, short-rod-shaped strain, designated YIM 004(T), was isolated from a forest-soil sample collected from Lijiang, Yunnan Province, China, and was investigated using a polyphasic taxonomic approach. The isolate contained chemotaxonomic markers that corresponded to those of its phylogenetic neighbour, Georgenia muralis, i.e. it possessed peptidoglycan type A4 alpha with lysine as the diagnostic cell-wall diamino acid, the predominant menaquinone was MK-8(H(4)) and the major fatty acid was ai-C(15 : 0). The G+C content of the genomic DNA was 72.9 mol%. Strain YIM 004(T) exhibited a 16S rRNA gene sequence similarity of 97.3 % and a DNA-DNA relatedness value of 18 % with respect to G. muralis DSM 14418(T). On the basis of the phenotypic and genotypic differences between the isolate and G. muralis, strain YIM 004(T) represents a novel species of the genus Georgenia, for which the name Georgenia ruanii sp. nov. is proposed. The type strain is YIM 004(T) (=CCTCC AB 204065(T)=DSM 17458(T)=KCTC 19029(T)). In addition, an emended description of the genus Georgenia is presented.

A new species of Harposporium parasitic on nematodes

A new species, Harposporium thaumasium X. Li et K.Q. Zhang, was isolated from forest soil in Yunnan, China. This species produces small, curved conidia, singly or in groups, from globose or ellipsoid phialides. Unlike other known Harposporium, this species produced novel arthroconidia that did not disarticulate at septa but germinated to produce typical phialides and infective conidia. Solitary or catenulate chlamydospores were also produced within infected nematodes and in pure culture. Narrowly elliptical to D-shaped accessory conidia were produced, only on potato dextrose agar and dextrose yeast agar, from mono- or poly-phialidic conidiogenous cells resembling Hirsutella; thus, on these nutrient media, four different spore types were formed. Infection tests showed that curved conidia of the species were capable of killing bacteria-feeding nematodes (Panagrellus redivivus) when ingested, and the infection was initiated by lodging of the conidia in the gut region. Accessory conidia were not observed to be infective or adhesive.Key words: endoparasitic fungi, Harposporium thaumasium sp.nov., ingested conidia, nematode.

Streptomyces roseoalbus sp. nov., an actinomycete isolated from soil in Yunnan, China

A strain YIM 33098T (= CCTCC AA001027T = DSM 41831T) was isolated from a forest soil sample collected from Nanning in Guangxi Province, China, in the course of screening for producers of new drug lead compounds. This strain was identified by using a polyphasic approach. The results showed that it should be assigned to the genus Streptomyces. An almost complete 16S rRNA gene sequence of the strain was determined and compared with those of representative Streptomyces species. Strain YIM 33098T was clustered in the same subclade with Streptomyces tendae ATCC19812T and Streptomyces eurythermus ATCC14975T. Similarities of strain YIM 33098T with the two strains were 97.35% and 97.42%, respectively. Based on the phenotypic and genotypic evidence, it is therefore proposed that strain YIM 33098T should be classified in the genus Streptomyces as a new species under the name of Streptomyces nanningensis sp. nov.

Bacillus nematocida sp. nov., a novel bacterial strain with nematotoxic activity isolated from soil in Yunnan, China

An endospore-forming bacterium, designated strain B-16 T, was isolated from a forest soil sample in Yunnan, China. The isolate presented remarkable nematotoxic activity against nematode Panagrellus redivivus. The organism was strictly aerobic, motile, spore forming and rod shaped, catalase- and oxidase-positive. The predominant isoprenoid quinone was menaquinone 7 (MK-7). The major cellular fatty acid profiles were anteiso-C 15:0 (48.67%), iso-C 15:0 (13.45%), C 16:0 (9.06%) and anteiso-C 17:0 (8.29%). The DNA G+C content was 46%. Phylogenetic analyses based on 16S rDNA sequence revealed that isolate belongs to the genus Bacillus. Strain B-16 T exhibited high 16S rDNA similarity with its closest neighbors Bacillus vallismortis (99.79%), B. subtilis (99.43%), B. atrophaeus (99.43%), B. amyloliquefaciens (99.36%), B. licheniformis (98.0%) and less than 97.0% with all the other relative type strains in the genus Bacillus. The phenotypic and genotypic characteristics and DNA–DNA relatedness data indicate that strain B-16 T should be distinguished from all the relative species of genus Bacillus. Therefore, on the basis of the polyphasic taxonomic data presented, a new species of the genus Bacillus, B. nematocida, with the type strain B-16 T (=CGMCC 1128 T) is proposed. The GenBank accession number for the sequence reported in this paper is AY820954.

Kribbella antibiotica sp. nov., a Novel Nocardioform Actinomycete Strain Isolated from Soil in Yunnan, China

A novel nocardioform actinomycete strain YIM 31530T was isolated from a soil in Yunnan, China. Based on the results of phenotypic characteristics, phylogenetic studies and DNA-DNA hybridization results, strain YIM 31530T should be assigned to a new species of the genus Kribbella, for which the name Kribbella antibiotica sp. nov. is proposed. The type strain is YIM 31530T(= CCTCC AA001021T = DSM 15501T). The GenBank accession number for the sequence reported in this paper is AY082063.