Forest Soil In China Research Articles

Fine root litter quality regulates soil carbon storage efficiency in subtropical forest soils

Decomposing root litter is a major contributor to soil carbon (C) storage in forest soils. During decomposition, the quality of root litter could play a critical role in soil C storage. However, it is unclear whether root litter quality influences soil C storage efficiency. We conducted a two-year greenhouse decomposition experiment using 13C-labeled fine root litter of two tree species to investigate how root litter quality, represented by C to nitrogen (C/N) ratios, regulates decomposition and C storage efficiency in subtropical forest soils in China. ‘High-quality’ root litter (C/N ratio = 26) decayed faster during the first year (0–410 days), whereas ‘low-quality’ root litter (C/N ratio = 46) decomposed faster toward the end of the two-year period (598–767 days). However, over the two years of the study, mass loss from high-quality root litter (29.14 ± 1.42%) was lower than ‘low-quality’ root litter (33.01 ± 0.54%). Nonetheless, root litter C storage efficiency (i.e., the ratio of new root litter-derived soil C to total mineralized root litter C) was significantly greater for high-quality root litter, with twice as much litter-derived C stored in soils compared to low-quality root litter at the end of the experiment. Root litter quality likely influenced soil C storage via changes in microbial diversity, as the decomposition of high-quality litter declined with increasing bacterial diversity, whereas the amount of litter-derived soil C from low-quality litter increased with fungal diversity. Our results thus reveal that root litter quality mediates decomposition and C storage in subtropical forest soils in China and future work should consider the links between root litter quality and soil microbial diversity.

Combined effect of biochar addition and temperature on methane absorption of topsoil in a temperate forest, China

Forest soil, especially temperate forest soil, is a prominent sink of atmospheric methane (CH4). Biochar has been increasingly applied to enhance CH4 uptake by soil. However, the effect of biochar size and temperature on CH4 uptake is still largely unknown. A series of incubation experiments were conducted to examine the single and combined effects of biochar addition and temperature (10 °C, 20 °C, and 30 °C) on CH4 uptake by temperate forest soil in China. The biochar was classified into three particle sizes (<0.1 mm, 0.1–0.5 mm, and 0.5–1 mm) and two application rates (0.73% and 3.65%, m: m). Results showed that the CH4 uptake was accelerated with the reduced particle sizes and the increased application rates of biochar. This variation was caused by two factors. Firstly, both the reduced particle sizes and increased application rates of biochar decreased the concentration of inorganic N, which had a negative relationship with CH4 uptake (P < 0.05). Secondly, the reduced particle sizes and increased application rates of biochar promoted both available phosphorus concentration and pH, and these two factors positively correlated with CH4 uptake (P < 0.05). The increased temperatures produced a negative effect on CH4 uptake (P < 0.05) due to the increased concentration of inorganic N after rising temperatures. Furthermore, the combined effect of biochar addition and increasing temperatures on CH4 uptake was antagonistic owing to the reduced Q10 value of CH4 uptake after biochar addition. This research highlights the importance of particle size of biochar on CH4 uptake. Our results also suggest that the positive effect of biochar addition on CH4 uptake may be dampened by global warming in the near future.

Isolation and Characterization of Bacillus Sp. Capable of Degradating Alkali Lignin

Alkali lignin-degrading Bacillus were isolated from forest soils in China and were identified as Bacillus subtilis TR-03 and Bacillus cereus TR-25 by 16S rDNA sequence analysis. Wherein TR-03 displayed optimal 26.72% alkali lignin (2 g/L) degradation at 7 days and 71.23% of Azure-B (0.01%) decolorization at 36 h of cultivation at 37°C. Ligninolytic enzyme analysis revealed that TR-03 was capable of depolymerizing alkali lignin effectively by the producing of lignin peroxidase and laccase, wherein higher laccase activity was cell-associated. At last, the physical and chemical changes of lignin via SEM and FTIR analysis was further observed to prove the lignin degradation by Bacillus subtilis TR-03.

Analysis of the Traits of Nitrogen Metabolism Pathways for Several Forest Soils in Eastern China

Nitrogen metabolism pathways mediated by microorganisms play an important role in maintaining the structure and functional stability of soil ecosystems. Clarifying the relationships between microbial communities and nitrogen metabolism pathways can expand our understanding of nitrogen metabolism pathways at a microscopic level. However, the horizontal gene transfer of microorganisms means that taxonomy-based methods cannot be easily applied. A growing number of studies have shown that functional traits affect community construction and ecosystem functions. Using methods based on functional traits to study soil microbial communities can, therefore, better characterize nitrogen metabolism pathways. Here, five typical forest soils in China, namely black soil(Harbin, Heilongjiang), dark-brown earth(Changbaishan, Jilin), yellow-brown earth(Wuhan, Hubei), red earth(Fuzhou, Fujian), and humid-thermo ferralitic soil(Ledong, Hainan), were selected to study the traits of nitrogen metabolism pathways using metagenomic technology combined with the trait-based methods. The studied nitrogen metabolism pathways were ammonia assimilation, nitrate dissimilatory reduction, nitrate assimilatory reduction, denitrification, nitrification, nitrogen fixation, and anaerobic ammonia oxidation. The results showed that bacteria dominated the metagenomic library, accounting for 98.02% of all the sequences. Across all domains, the most common pathway was ammonia assimilation. For example, an average of 2830 ammonia assimilation pathway genes were detected for every million annotated bacterial sequences. In comparison, nitrogen fixation and anaerobic ammonia oxidation were the least detected pathways, accounting for 28.3 and 10.7 per million sequences, respectively. Different microorganisms can participate in a same nitrogen metabolism pathway, and the community structure of different soils was variable. The five typical forest soils in China show the same microbial nitrogen metabolism pathway traits; however, the community structure of the microorganisms mediating these processes was found to vary.

Key factors shaping prokaryotic communities in subtropical forest soils

Microorganisms in subtropical forest soils are responsible for various ecological functions such as decomposing organic matter and driving carbon and nitrogen cycles. It is essential to understand how environmental factors affect microbial community composition and diversity. Prokaryotic communities (including bacteria and archaea) were investigated according to soil layer (0–2 cm and 18–20 cm), forest type (mountain dwarf forest, Guangdong pine forest, and monsoon evergreen broadleaf forest) and season (summer and winter) in Guangdong Nanling National Natural Reserve in China by Miseq sequencing of 16S rRNA genes. This study reveals key factors that shaped prokaryotic community structure and diversity in subtropical forest soils in China. Results show that Acidobacteria and Proteobacteria were the dominant phyla, with a relative abundance of 54.2% and 20.7% respectively. Soil pH, organic matter, total N, hydrolysable N, available P, NO3−, and NH4+ were significantly correlated with prokaryotic community structure and diversity. Soil layer significantly affected prokaryotic community structure and diversity. Forest type significantly influenced prokaryotic community structure but not diversity. Season did not significantly correlate with prokaryotic community structure or diversity.

Bacillus dafuensis sp. Nov., Isolated from a Forest Soil in China.

A Gram-staining-positive, motile, rod-shaped, aerobic bacterial strain FJAT-25496T was isolated from a forest soil sample collected from Dafu County, Chengdu City, Sichuan Province, China. Strain FJAT-25496T grew at 15-50°C (optimum 35°C), pH 6.0-10.0 (optimum 8.0), and NaCl tolerance of 0-4.0% (w/v) (optimum 0%). The strain contained iso-C15:0 and anteiso-C15:0 as the predominant cellular fatty acids as well as MK-7 as the only menaquinone. The major polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), and phosphatidyl glycerol (PG). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain FJAT-25496T was a member of the genus Bacillus, and most closely related to Bacillus solani FJAT-18043T (97.8%), Bacillus praedii FJAT-25547T (97.8%), Bacillus depressus BZ1T (97.7%), Bacillus oceanisediminis H2T (97.7%), and Bacillus ciccensis 5L6T (97.6%). Based on complete genome comparisons between strain FJAT-25496T and the type strains of its closely related species, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were 73.4-76.3% and 21.7-23.2%, respectively. The genomic DNA G + C content of strain FJAT-25496T was 36.9%. On the basis of phenotypic, phylogenetic, chemotaxonomic, and genomic features, strain FJAT-25496T is considered to represent a novel species of the genus Bacillus, for which the name Bacillus dafuensis sp. nov. is proposed. The type strain is FJAT-25496T (= CCTCC AB 2019182T = KCTC 43120T).

Pseudomonas hydrolytica sp. nov., multiple polymer-degrading bacteria isolated from soil in China.

A short rod-shaped, Gram-stain-negative strain that can degrade multiple polymers was isolated from forest soil in China and designated as DSWY01T. The results of 16S rRNA gene sequence analysis showed that this isolate shared high similarities with Pseudomonas alcaliphila NBRC 102411T (99.3 %), Pseudomonas mendocina NBRC 14162T (99.2%) and Pseudomonas oleovorans NBRC 13583T (99.0%). The results of phylogenetic analysis based on 16S rRNA gene sequence and multilocus sequence analysis (recA, gyrB, nuoD, glnS and rpoD) indicated that strain DSWY01T belongs to the genus Pseudomonas and is a member of the P. oleovorans group in an independent branch. The average nucleotide identity and digital DNA-DNA hybridization between the genome of strain DSWY01T and the genomes of other species (ANIb 77.72-89.65 %; GGDC 15.50-31.10 %) showed that the isolate represents a novel species. The DNA G+C content of strain DSWY01T was 63.67 mol%, and the major cellular fatty acids (>15 %) were a mixture of C18 : 1ω7c/C18 : 1ω6c and C16 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and two unidentified lipids, and the major quinone was CQ-10. The morphological, physiological and biochemical characteristics of the isolate were then compared with those of reference type strains. The isolate differed considerably from its closest relatives and is representative of a novel species of Pseudomonas, for which the name Pseudomonas hydrolytica sp. nov. is proposed. The type strain is DSWY01T (=DSM 106702T=CCTCC AB 2018053T).

Land-use changes alter soil bacterial composition and diversity in tropical forest soil in China

Tropical forests, under pressure from human activities, are important reservoirs of biodiversity and regulators of global biogeochemical cycles. Land-use and management are influential drivers of environmental change and ecosystem sustainability. However, only limited studies have analysed the impacts of planting age and vegetation type under land-use change on soil microbial community in tropical forests simultaneously. Here, we assessed soil bacterial community composition and diversity under different land-use in Hainan Province, China, using high-throughput sequencing combined with PICRUSt analysis. Land-use included natural forest, 5-year-old cropland, young (5-year-old) rubber tree plantation, and old (30-year-old) rubber tree plantation. Land-use changes altered the soil bacterial community composition but had a non-significant influence on alpha diversity (P > .05). We found that bacterial beta-diversity significantly decreased in young rubber tree plantation soils and cropland soils compared to natural forest as a control. In contrast, soil bacterial beta-diversity increased in old rubber tree plantation soils, indicating the effects of time since planting. There was no difference in microbial beta-diversity between soils from cropland and young rubber tree plantation. Soil bulk density and moisture, not pH, were the main environmental factors explaining the variability in microbial diversity. PICRUSt analysis of soil bacterial predicted gene abundances within metabolic pathways and indicated that land-use change altered soil functional traits, e.g., amino acid-related enzymes, ribosomes, DNA repair/recombination proteins and oxidative phosphorylation. Also, vegetation type, not planting age, had significant impacts on soil functional traits. Overall, planting age had the greatest influence on soil bacterial beta-diversity, while vegetation type was more crucial for soil functional traits (P < .05).

Molecular Signatures of Three Fulvic Acid Standard Samples as Revealed by Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

AbstractIt is necessary to understand the molecular composition of fulvic acid (FA), which plays a significant role in the transport and bioavailability of pollutants in the environment. FA collected from Suwannee River in South Georgia (SRFAriver) and Elliott soil in fertile prairie of Illinois (ESFAsoil) are two standard fulvic acid samples of International Humic Substances Society (IHSS). FA collected from Beijing Jiufeng forest soils in China (JFFAsoil) was extracted according to the standard method recommended by IHSS. In this study, the compositions of three FA from two origins (i. e. river and soil) are characterized using negative ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT‐ICR MS). Compounds possessing higher aromaticity usually contain more nitrogen or sulfur atoms. The aromaticity and humification degree of soil‐derived FA are higher. Soil‐derived FA contains more nitrogen and sulfur elements because compounds containing nitrogen and sulfur atoms are easily absorbed by clay minerals and preserved in aromatic molecules. Comparing the two soil‐derived FA, they differed little in formula and component compositions, but JFFAsoil was slightly more aromatic and less labile than ESFAsoil. These are useful for understanding the difference between the carbon, nitrogen and sulfur element enrichment process in the formation of fulvic acid in river and soil environment at the molecular level.

High hydrogen sulfide emissions from subtropical forest soils based on field measurements in south China

The present estimate of global hydrogen sulfide (H2S) emission from natural sources has large uncertainty mainly due to the lack of valid field data, particularly for subtropical forest soil in China with elevated atmospheric S deposition. In this study, the field observation of H2S fluxes over subtropical forest soil was conducted for the first time in south China to measure the magnitude of emissions of H2S, and evaluate its contribution to the large S sink, using the Dynamic Flux Chamber (DFC) method. Daily variations of H2S fluxes showed an increasing emission with the increasing air temperature in the morning, a peak at the middle of the day, and a decreasing emission thereafter, then approximated to zero at night. The H2S flux had positive values in all seasons, with the highest in summer, followed by spring, and relatively lower values in fall and winter. The H2S flux measurements showed relatively large emission with annual average value of 0.028 g S m−2 yr−1, possibly due to the elevated sulfate concentration in the soil solution by S deposition, the hot and humid climate, as well as the lower soil pH in subtropical China. Thus, not only tropical, subtropical soils need to be included as significant H2S sources to accurately portray the global H2S budget. Although the soil in subtropical forests acted as a strong source for H2S to atmosphere, H2S emission from soil had limited contribution (about 0.2%) to the large S sink in this forest catchment.

Occurrence and distribution of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in natural forest soils: A nationwide study in China

Forests serve as the primary reservoir for organic carbon above ground. Previous studies have revealed that forest soils play key roles in the retention of persistent organic pollutants (POPs). In this study, the occurrence and distribution of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) were investigated in 54 surface soil samples from 28 natural forested mountain sites across China between 2012 and 2013. The detection frequency of PFOA (70%) was significantly higher than that of PFOS (4%). PFOA levels ranged from <0.9 to 9.0 pg·g−1 dry weight (dw). Levels of PFOA and PFOS in forest soils were significantly lower than those in agricultural, urban and rural areas in China. Relatively high levels of PFOA were detected in Hubei Province (Jiugong Mountain, average: 3.4 pg·g−1 dw) and Jiangxi Province (Wugong Mountain, average: 4.4 pg·g−1 dw), where many domestic fluoropolymer manufacturers are located. PFOS was only detected in these two provinces (2.2 pg·g−1 dw and 2.7 pg·g−1 dw, respectively). From most of the surveyed mountains, the concentrations of PFOA increased with elevation. The lower temperature and greater precipitation probably made PFOA and its precursors available to transport and degrade more readily at higher altitude sites. A relatively higher level (1.9 ± 1.3 pg·g−1 dw) of PFOA was found in the broadleaf evergreen forest area, mainly due to the high industrial emissions, plant retention, and precipitation rate in this area. Source were the dominant factor controlling the spatial distribution of PFOA in natural forest soils in China.

Changes in methane oxidation ability and methanotrophic community composition across different climatic zones

Purpose Microbial oxidation by bacteria with the potential to oxidize C1 compounds (methanotrophs) is the only biological sink for atmospheric methane (CH4). Aerobic methanotrophs are particularly active in forest soils, but the role of aerobic methanotrophs in native forest soils in China remains poorly understood. The pmoA gene, encoding the key enzyme methane monooxygenase (particulate MMO), is widely used to identify methanotrophic communities.

Heterotrophic nitrification is responsible for large rates of N2O emission from subtropical acid forest soil in China

SummarySubtropical acidic forest soil is an important source of global nitrous oxide (N2O). However, the rates of autotrophic nitrification and denitrification in such soil are less than in temperate forest soil. We hypothesized that this difference is related to different N2O production pathways. We carried out paired 15N‐labelling experiments under aerobic conditions (60% water‐holding capacity) in the laboratory to compare N2O production pathways between subtropical and temperate forest soils to determine the differences in N2O production based on controlling factors. Our results showed that the contributions of NH4+ oxidation to NO3− to total N2O production (CNH4) were small in all soils studied (21–30%). Contributions of denitrification to total N2O production (CNO3) in subtropical forest soil (34%) were significantly less than those in temperate forest soil (54%). However, rates of N2O emission from denitrification (N2Od) were similar between subtropical and temperate forest soils, indicating that denitrification was probably not the predominant process causing the difference between the rates of N2O production in these soils. The average contribution of heterotrophic nitrification to total N2O production (CON) was significantly larger in subtropical forest soil (45%) than in temperate forest soil (15%). Soil pH and the C:N ratio were identified as key factors, with CON negatively correlated with soil pH (r = −0.60, P &lt; 0.05) and positively correlated with soil C:N ratio (r = 0.78, P &lt; 0.01), although the significance was probably weakened when forest types were taken into consideration. The rate of N2O production by heterotrophic nitrification (N2Oh) (average, 3.0 μg N kg−1 day−1) was also significantly larger in subtropical forest soil than in temperate forest soil (average, 0.7 μg N kg−1 day−1). Therefore, based on this study, the heterotrophic N2O pathway seems responsible for the larger N2O production in subtropical acid forest soil than in temperate forest soil. This study is among the first to elucidate in detail contributions to the processes of N2O production and to account for its large rates of production in subtropical acidic forest soil in China, which has implications for the prediction of N2O production in forest soil using ecosystem modelling.HighlightsExamined N2O production pathways in subtropical and temperate forest soils. Rate of N2O emission in subtropical forest soil was larger than temperate forest soil. Heterotrophic nitrification was responsible for large N2O production in subtropical soil. Soil pH and C:N ratio were identified as key factors affecting the N2O production pathway.

The contribution of atmospheric deposition and forest harvesting to forest soil acidification in China since 1980

Soils below croplands and grasslands have acidified significantly in China since the 1980s in terms of pH decline in response to acid inputs caused by intensified fertilizer application and/or acid deposition. However, it is unclear what the rate is of pH decline of forest soils in China in response to enhanced acid deposition and wood production over the same period. We therefore gathered soil pH data from the Second National Soil Inventory of China and publications from the China National Knowledge Infrastructure (CNKI) database in 1981–1985 and 2006–2010, respectively, to evaluate the long-term change of pH values in forest soils. We found that soil pH decreased on average by 0.36 units in the period 1981–1985 to 2006–2010., with most serious pH decline occurring in southwest China (0.63 pH units). The soil type with the strongest pH decline was the semi-Luvisol (0.44 pH units). The decrease in pH was significantly correlated with the acid input induced by atmospheric deposition and forest harvesting. On average, the contribution of atmospheric deposition to the total acid input was estimated at 84% whereas element uptake (due to forest wood growth and harvest) contributed 16% only. Atmospheric deposition is thus the major driver for the significant forest soil acidification across China.

The mechanisms governing low denitrification capacity and high nitrogen oxide gas emissions in subtropical forest soils in China

Previous studies have demonstrated that denitrification rates are low in subtropical forest soils. However, the mechanisms governing this process are not well known. This study seeks to identify the mechanisms responsible for the low denitrification capacity and high nitrogen oxide gas ratio in subtropical forest soils in China. The denitrification capacity and nitric oxide (NO), nitrous oxide (N2O), and dinitrogen (N2) emission rates were measured using the acetylene inhibition method under conditions of added nitrate and anoxia. The abundance of nitrate reductase (narG), nitrite reductase (nirK), nitric oxide reductase (cnorB), and nitrous oxide reductase (nosZ) was measured using real-time, quantitative polymerase chain reaction, and sequencing of the nirK and norB products was performed to analyze the population structure of denitrifying bacteria. These results showed that the denitrification capacity in subtropical forest soils was lower than in temperate forest soils (p < 0.05). Multiple regression analysis showed that redox potential at the start of incubation (Ehi), rather than soil pH or soil organic C, was the key soil variable influencing denitrification, and Ehi alone could explain 68% of the variations in denitrification capacity. The high Ehi in subtropical soils led to a low abundance of nirK and significant differences in the population structure of denitrifying bacteria between subtropical and temperate soils. Therefore, Ehi was responsible for the low denitrification capacity in subtropical forest soils. The ratio of NO to total denitrification gas products (p < 0.01) and the ratio of NO and N2O to total denitrification gas products (p < 0.05) were significantly higher in subtropical forest soils than in temperate forest soils, while the reverse trend was observed for the ratio of N2 to total denitrification gas products (p < 0.05). A high Ehi reduced the specific reduction activity of each nosZ copy and, in turn, resulted in a large ratio of NO and N2O to total denitrification gas products in subtropical soils. Thus, NO and N2O, but not N2, were the dominant denitrification gas products, accounting for 80%, even under the highly anaerobic conditions in subtropical forest soils and despite low denitrification capacity. These results were significant for understanding the “Hole in the Pipe” model and NO and N2O gases emission in subtropical forest soils. Despite the fact that the nitrogen flowing through the pipe (denitrification capacity) was low, the large holes in the pipe resulted in a large quantity of NO and N2O gases leaking out. This leakage may be a potential mechanism for the high levels of NO and N2O gas emission in subtropical forest soils and could partly explain why NO and N2O emissions are generally high in subtropical and tropical soils.

N 2O production pathways in the subtropical acid forest soils in China

To date, N 2O production pathways are poorly understood in the humid subtropical and tropical forest soils. A 15N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N 2O production in four subtropical acid forest soils (pH<4.5) in China. The results showed that denitrification was the main source of N 2O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N 2O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%–52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%–41.8% of N 2O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N 2O–N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N 2O product ratios from nitrification. The ratio of N 2O–N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget.

Jeotgalibacillus soli sp. nov., isolated from non-saline forest soil, and emended description of the genus Jeotgalibacillus

A Gram-stain-positive, endospore-forming, motile, catalase- and oxidase-positive, aerobic, rod-shaped bacterium, designated strain JSM 081008(T), was isolated from non-saline forest soil in China. Strain JSM 081008(T) was able to grow with 0-20% (w/v) NaCl, at pH 6.0-10.5 and at 10-45 degrees C; optimum growth was observed with 2-5% (w/v) NaCl, at pH 7.0-8.0 and at 30-35 degrees C. The peptidoglycan type was A1alpha linked directly through L-Lys. The major cellular fatty acids (>10% of the total) were anteiso-C15:0, iso-C15:0, anteiso-C17:0 and C16:0. The predominant respiratory quinone was menaquinone 7 and the genomic DNA G + C content of the strain was 42.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JSM 081008(T) should be assigned to the genus Jeotgalibacillus and was related most closely to the type strains of Jeotgalibacillus alimentarius (sequence similarity 99.4%) and Jeotgalibacillus salarius (97.0%), followed by Jeotgalibacillus campisalis (95.4%) and Jeotgalibacillus marinus (95.2%). The combination of phylogenetic analysis, DNA-DNA relatedness values, phenotypic characteristics and chemotaxonomic data supports the view that strain JSM 081008(T) represents a novel species of the genus Jeotgalibacillus, for which the name Jeotgalibacillus soli sp. nov. is proposed. The type strain is JSM 081008(T) (=DSM 22174(T) = KCTC 13528(T)). An emended description of the genus Jeotgalibacillus is also presented.

Yaniella soli sp. nov., a new actinobacterium isolated from non-saline forest soil in China

A novel Gram-stain-positive, slightly halophilic, facultatively alkaliphilic, non-motile, non-sporulating, catalase-positive, oxidase-negative, aerobic bacterium, designated strain JSM 070026(T), was isolated from non-saline forest soil in China. Growth occurred with 0-20% (w/v) NaCl (optimum, 2-4%) and at pH 6.0-10.5 (optimum, pH 8.0) and 5-40 degrees C (optimum, 30 degrees C). Good growth also occurred in the presence of 0-28% (w/v) KCl (optimum, 2-5%) or 0-25% (w/v) MgCl(2)*6H(2)O (optimum, 1-4%). The peptidoglycan type was A4alpha (L: -Lys-Gly-L: -Glu). Cell-wall sugars contained mannose and xylose. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0. Strain JSM 070026(T) contained menaquinone 8 as the major respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the major polar lipids. The DNA G + C content of strain JSM 070026(T) was 56.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JSM 070026(T) was a member of the suborder Micrococcineae and most closely related to Yaniella flava YIM 70178(T) (sequence similarity 99.4%) and Yaniella halotolerans YIM 70085(T) (97.9%). The three strains formed a distinct branch in the phylogenetic tree. The combination of phylogenetic analysis, DNA-DNA relatedness values, phenotypic characteristics and chemotaxonomic data supports the proposal that strain JSM 070026(T) represents a novel species of the genus Yaniella, for which the name Yaniella soli sp. nov. is proposed. The type strain is JSM 070026(T) (=DSM 22211(T) = KCTC 13527(T)).

Sphaerisporangium flaviroseum sp. nov. and Sphaerisporangium album sp. nov., isolated from forest soil in China

Two Gram-positive, aerobic actinomycete strains, designated YIM 48771(T) and YIM 48782(T), were isolated from virgin forest soil samples collected in Hunan Province, China. 16S rRNA gene sequence similarities of the two novel isolates ranged from 96.3 to 97.6 % with species of the genus Sphaerisporangium with validly published names but, in the tree based on 16S rRNA gene sequences, the isolates formed distinct phyletic lines. The level of 16S rRNA gene sequence similarity between the two novel isolates was 97.1 %. DNA-DNA hybridization of strains YIM 48771(T) and YIM 48782(T) with recognized species of the genus Sphaerisporangium revealed that the level of DNA-DNA relatedness was below 70 %. The DNA G+C contents of strains YIM 48771(T) and YIM 48782(T) were 67.1 and 71 mol%, respectively. Chemotaxonomic data [major menaquinone, MK-9(H(4)); major polar lipids, diphosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylethanolamine and phosphoglycolipids; major fatty acids, iso-C(16 : 0) and 10-methyl C(17 : 0)] supported the affiliation of the two isolates with the genus Sphaerisporangium. The results of DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of the two isolates from recognized Sphaerisporangium species. Based on morphological, chemotaxonomical and phylogenetic data, strains YIM 48771(T) and YIM 48782(T) are considered to represent two novel species of the genus Sphaerisporangium, for which the names Sphaerisporangium flaviroseum sp. nov. (type strain, YIM 48771(T)=DSM 45170(T)=KCTC 19393(T)) and Sphaerisporangium album sp. nov. (type strain, YIM 48782(T)=DSM 45172(T)=CCTCC AA 208026(T)) are proposed.

A Review of the Forest Soils in China

A Review of the Forest Soils in China