首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 125 毫秒
1.
Bacteriophages (phages) are the most abundant biological entities on the planet and are important as the greatest genomic reservoirs in both marine and terrestrial environments. In this study, we analysed T4-type phage communities in an upland black soil by monitoring g23 clones in DNA extracted from seasonal soil samples with no fertilizer, chemical fertilizers, chemical fertilizers plus manure, and natural restoration treatments. PCR products with degenerate primers MZIA1bis and MZIA6 were subjected to denaturing gradient gel electrophoresis. In total, 46 clones with different g23 sequences were obtained. Phylogenetic analyses indicated that T4-type phage communities in the upland black soil were distinctly different from those in marine environments and in an Antarctic lake, which strongly suggested that T4-type phage communities in soil differed from those in aquatic environments. Among 46 clones, 18 clones formed clusters with the clones from rice field soils, 14 clones formed three new clusters, and 13 clones were left as ungrouped, which indicated that T4-type phage communities in the upland black soil were relatively similar to those in rice field soils but that specific communities also inhabit in the upland black soil exclusively.  相似文献   

2.
Our previous study indicated that the diversity of the major capsid gene (g23) of T4-type bacteriophages (phages) of Novosphingobium and Sphingomonas strains isolated from the floodwater of a Japanese paddy field is comparable to those of the clones obtained from other Japanese paddy fields. For more strict comparison of the diversity, this study examined g23 sequences between Novosphingobium and Sphingomonas phages and phage communities in the identical floodwater of a Japanese paddy field. The clones were obtained by applying g23-specific primers to DNA extracted from the floodwaters. Many 23 clones in the floodwater were grouped into the same clusters of Paddy Groups I-VI with g23 genes of Novosphingobium/Sphingomonas phages with some clones belonging to an additional cluster. In addition, the remaining clones belonged to the clusters of marine clones and T4-type enterophages. These findings indicate that the g23 genes in the floodwater are more diversified than those of Novosphingobium/Sphingomonas phages including g23 genes closely related to the genes of enterophages and marine origins.  相似文献   

3.
Our previous study revealed the high diversity of the major capsid gene (g23) of T4-type phages that existed in the paddy field soils in Northeast China. In this study, the phylogeny and genetic diversity of the g23 gene in the paddy floodwater samples collected from five sampling sites at three sampling times during the rice (Oryza sativa L.) growth season in Northeast China are reported. In total, 104 different g23 clones were isolated, among which 50% of the clones exhibited the highest identities with the clones retrieved in paddy soils and upland black soils. The remaining clones had the highest identities with lake origins. Phylogenetic analysis revealed that 43% of the g23 clones grouped into three novel subgroups which included the clones unique to paddy floodwater, and no g23 sequences obtained in paddy floodwater fell into the paddy soil groups II, III, IV, V, VI, VII and NPC-A. UniFrac analysis of g23 clone assemblages demonstrated that T4-type phage communities in paddy floodwater were changed spatially and temporally, and the communities were different from those in paddy soils. Further comparison of the g23 clone assemblages from different environments demonstrated that T4-type phages were biogeographically distributed, and the distribution was both affected by geographical separation and ecological processes across the biomes.  相似文献   

4.
Many studies have shown the ecological importance of viruses as the greatest genomic reservoirs on the planet. As bacteriophages (phages) comprise the majority of viruses in the environment, we surveyed the capsid genes (g23) of T4-type phages, Myoviridae, from DNA extracts of three paddy field soils located in northern, central and southern Japan using the degenerate primers MZIA1bis and MZIA6. Denaturing gradient gel electrophoresis (DGGE) was performed to separate PCR-amplified g23 products, and 56 DGGE bands were identified as g23 fragments. Only nine clones were grouped into T-evens, PseudoT-evens and ExoT-evens, and most of the other clones were classified into Paddy Groups I-VI. No significantly different distribution of g23 clones was observed among the paddy fields at the group level, indicating that phage communities estimated from the g23 composition were common on the nationwide level. Comparison of g23 sequences showed that g23 genes in paddy fields were different from those in marine environments, and more divergence of g23 genes was estimated in the paddy fields compared to the marine environment. Two novel g23 clones with very short amino acid residues were detected, suggesting the existence of uncharacterized, novel groups of g23 genes in paddy field soils.  相似文献   

5.
Phylogenetic positions of characteristic bands of 16S rDNA that were obtained from the floodwater of a Japanese paddy field by denaturing gradient gel electrophoresis (DGGE) analysis in a previous work (Biol Fertil Soils 36:306–312, 2002) were determined to identify dominant bacterial members in the floodwater. Sequences of DGGE bands were affiliated with the Cytophaga–Flavobacterium–Bacteroides group, β-Proteobacteria, and Actinobacteria and showed phylogenetically close relationships with species inhabiting other aquatic environments, although most of their closest relatives were uncultured bacterial clones.  相似文献   

6.
Viruses exist everywhere on the planet. Recent development in viral genomics confirmed that genomic information is preserved among viral subsets and can be used for phylogenetic classification of viruses and for evaluation of viral diversity in the environment. The capsid gene of T4-type bacteriophages, g23, is the most widely applied gene for evaluating the diversity of the T4-type bacteriophage family. In this study, we applied denaturing gradient gel electrophoresis to PCR products of DNA with g23-specific primers that were extracted from a Japanese paddy field under long-term fertilizer trial and obtained 39 different g23 clones at the DNA level. They showed identities of 27–99% with the clones within the NCBI database at the amino acid level. They were quite distinctive from those obtained in marine environments and most of them formed six phylogenetically novel groups in the T4-type bacteriophage family with the clones obtained from another paddy field. The existence of six novel groups was confirmed from molecular analysis of all the amino acid sequences between the primers, of the amino acid sequences excluding hypervariable region, and of those of conserved regions. These findings indicate that T4-type bacteriophage communities in paddy fields consist of previously uncharacterized members phylogenetically distant from those in marine environments. The type of fertilizers and the stage during rice cultivation were not the major factors in determining T4-type bacteriophage communities in the paddy field.  相似文献   

7.
We surveyed the major capsid genes (g23) of T4-type bacteriophages using the primers MZIA1bis and MZIA6 and DNA extracted from seven upland black soils in Northeast China. In total, 99 different g23 clones were obtained. Approximately half of the clones fell into paddy groups, whereas the rest belonged to one of several groups containing only clones from upland black soils or remained ungrouped, suggesting that the T4-type phage communities in the upland black soil were relatively similar to those in paddy field soils but that specific communities exclusively inhabit the upland black soil. UniFrac analysis of all of the g23 clones obtained from various environments indicated that the T4-type phage communities varied among marine, lake, paddy field soil and upland soil environments and that the T4-type phage communities in upland black soils varied by sampling location.  相似文献   

8.
We surveyed the capsid genes (g23) of T4-type bacteriophages in DNA extracted from fifteen rice field soils in Northeast China using primers MZIA1bis and MZIA6. Denaturing gradient gel electrophoresis (DGGE) was performed to separate PCR-amplified g23 products. In total, 53 DGGE bands were identified as g23 clones, nine of which belonged to a novel, Northeast China-specific group. In addition, four and six clones formed two novel groups with previously ungrouped clones obtained from Japanese rice fields. The majority of the remaining clones fell into Paddy Groups I and V, none of the clones belonged to Paddy Groups II, III, IV, and VI, indicating that phylogenetic distribution of g23 genes in rice fields in Northeast China was different from that in Japanese rice fields.  相似文献   

9.
Abstract

Viruses are the most abundant biological entities in marine and freshwater environments. Many studies have shown the ecological importance of viruses in the primary production and microbial food web in aquatic environments. However, no studies have examined viral abundance in the floodwater of paddy fields. The present study surveyed the abundance of virus-like particles (VLPs) and bacteria in the floodwater of a Japanese paddy field under a long-term fertilizer trial since 1925 during the rice cultivation period. Virus-like particles and bacterial abundances in the floodwater ranged from 5.6 × 106 to 1.2 × 109 VLPs mL?1 and from 9.2 × 105 to 4.3 × 108 cells mL?1 with mean abundances of 1.5 × 108 VLPs mL?1 and 5.1 × 107 cells mL?1, respectively, and increased with an increase in the turbidity of the floodwater with suspended particles. The magnitude of seasonal variation was more than 50-fold for VLP abundance and 100-fold for bacterial abundance. The virus-to-bacterium ratios fluctuated over the rice cultivation period, ranging from 0.11 to 72 and their increase correlated with the decrease in bacterial abundance. Our results suggest that viral abundance in the floodwater of paddy fields is larger than in natural marine and freshwater environments.  相似文献   

10.
The study was carried out between 2008 and 2010 on 8-year-old pomegranate (Punica granatum L.) trees cultivar ‘Kandhari Kabuli.’ The potential efficiency of bio-organics used along with chemical fertilizers on cropping behavior, quality attributes, nutrient availability, physico-chemical, and biological properties of soil were investigated. Bioorganic nutrient sources, namely, vermicompost (VC), biofertilizers (BF), farm yard manure (FYM), and green manure (GM), along with chemical fertilizers was evaluated in 13 different treatment combinations. Conjoint treatment application of VC at 20 kg tree?1, BF at 80 g tree?1, FYM at 20 kg tree?1, GM as sun hemp (Crotalaria juncea L.) along with 75% of the recommended dose of nitrogen–phosphorus–potassium (N–P–K) chemical fertilizers significantly resulted in maximum fruit set (52.03%) and fruit yield (34.02 kg tree?1). All of the fruit quality characteristics were also improved significantly when compared to nitrogen–phosphorus–potassium (N–P–K) chemical fertilizers. This superior combination also enhanced physical-chemical and biological properties of the rhizosphere soil. Microbial biomass of in terms of Pseudomonas, total culturable soil fungi, Azotobacter chroococcum, actinobacteria, and arbuscular mycorrhizal (AM) fungi improved 385.57, 60.26, 134.19, 168.02, and 39.87%, respectively, over control. This combination also resulted in considerable greater concentration of leaf macro-and micronutrients: N (2.63%), P (0.25%), K (1.57%), iron (Fe; 197.87 mg kg?1), copper (Cu; 14.65 mg kg?1), zinc (Zn; 59.36 mg kg?1), and manganese (Mn; 200.45 mg kg?1).  相似文献   

11.
ABSTRACT

A long-term field experiment was performed to assess the effects of fertilization regimes on greenhouse gas emissions, soil properties, soil denitrifies, and maize (Zea mays) grain yield on Mollisols of Northeastern China. Chemical nitrogen (N), phosphorus (P), and potassium (K) fertilizers plus pig manure (MNPK) treatment significantly increased soil N2O emissions by 29.9–226.4% and global warming potential (GWP) by 29.8–230.7% compared to unfertilized control (CK), chemical N fertilizer only (N), chemical N, P, and K fertilizers (NPK) and chemical N, P, and K fertilizers plus corn straw (SNPK) treatments. However, the MNPK treatment yielded similar greenhouse gas intensity (GHGI) as compared with other treatments, mainly due to higher maize grain yield. There were also higher gene copy numbers of nirK, nirS, and nosZ in topsoil (0–20 cm depth) under MNPK treatment. Automatic linear modeling analysis indicated that main factors influencing soil N2O emissions were soil organic carbon (SOC), NO3? content, and nirK gene abundance. Although the application of chemical fertilizers plus organic manure increases N2O emissions due to higher N and C availability and nirK gene activity in the soil, this is still a promising fertilizer management due to its notable enhancement of maize grain yield and SOC content.  相似文献   

12.
Background, Aims, and Scope  Knowledge about shifts of microbial community structure and diversity following different agricultural management practices could improve our understanding of soil processes and thus help us to develop sound management strategies. A long-term fertilization experiment was established in 1989 at Fengqiu (35°00′N, 114°24′E) in northern China. The soil (sandy loam) is classified as aquic inceptisols and has received continuous fertilization treatments since then. The fertilization treatments included control (CK, no fertilizer), chemical fertilizers nitrogen (N) and potassium (K) (NK), phosphorous (P) and K (PK), NP, NPK, organic manure (OM), and half chemical fertilizers NPK plus half organic manure (1/2NPKOM). The objective of this study was to examine if the microbial community structure and diversity were affected by the long-term fertilization regimes. Materials and Methods  Soil samples were collected from the long-term experimental plots with seven treatments and four replications in April 2006. Microbial DNAs were extracted from the soil samples and the 16S rRNA genes were PCR amplified. The PCR products were analyzed by DGGE, cloning and sequencing. The bacterial community structures and diversity were assessed using the DGGE profiles and the clone libraries constructed from the excised DGGE bands. Results  The bacterial community structure of the OM and PK treatments were significantly different from those of all other treatments. The bacterial community structures of the four Ncontaining treatments (NK, NP, NPK and 1/2NPKOM), as well as CK, were more similar to each other. The changes in bacterial community structures of the OM and PK treatments showed higher richness and diversity. Phylogenetic analyses indicated that Proteobacteria (30.5%) was the dominant taxonomic group of the soil, followed by Acidobacteria (15.3%), Gemmatimonadetes (12.7%), etc. Discussion  Irrespective of the two fertilization treatments of OM and PK, the cluster analysis showed that bacterial communities of the remaining five treatments of CK, NK, NP, NPK and 1/2NPKOM seemed to be more similar to each other, which indicated the relatively weak effects of the four N-containing treatments on soil bacterial communities. N fertilizer may be considered as a key factor to counteract the effects of other fertilizers on microbial communities. Conclusions  Our results show that long-term fertilization regimes can affect bacterial community structure and diversity of the agricultural soil. The OM and PK treatments showed a trend towards distinct community structures, higher richness and diversity when compared to the other treatments. Contrasting to the positive effects of OM and PK treatments on the bacterial communities, N fertilizer could be considered as a key factor in the soil to counteract the effects of other fertilizers on soil microbial communities. Recommendations and Perspectives  Because of the extremely high abundance and diversity of microorganisms in soil and the high heterogeneity of the soil, it is necessary to further examine the effects of fertilization regimes on microbial community and diversity in different type soils for comprehensively understanding their effects through the appropriate combination of molecular approaches. ESS-Submission Editor: Chengrong Chen, PhD (c.chen@griffith.edu.au)  相似文献   

13.
  相似文献   

14.
Percolating water was sampled from the plow layer and subsoil layer in a Japanese paddy field, and the bacterial communities were compared together with floodwater by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) targeting a partial 16S rRNA gene and subsequent sequencing. The number of DGGE bands ranged from 16 to 28 with no significant differences among the sampling sites and times. Only 2 bands were common for the three sources of water samples. DGGE bands specific for the floodwater samples and percolating water samples from the plow layer were identified, while percolating water samples from the subsoil layer did not show specific bands but displayed common bands to those of the floodwater samples (7 bands) and percolating water samples from the plow layer (1 band). Cluster analysis of the DGGE banding patterns showed a distinct clustering in the samples of percolating water from the plow layer and a closer relationship between the others. These results suggest that the bacterial communities in percolating water changed during downward movement through the plow layer and subsoil layer. Sequences of the DGGE bands specific for the samples of percolating water from the plow layer showed a close relationship with anaerobic bacteria such as iron-reducers or uncultured bacterial DNA isolated from environments that are considered to be less oxic. On the other hand, the sequences of the bands specific for the samples of floodwater and percolating water from the subsoil layer showed a close relationship with uncultured bacterial DNA isolated from freshwater environments.  相似文献   

15.
In this study, effects of foliar application (with constant 0.2% concentration) of chemical NPK (N20:P10:K20) and organic fertilizers of Biomin (an organic aminochelate fertilizer), Humifolin (a humic acid based fertilizer), Biomin?+?Humifolin, a synthetic macro-micro mixture, soil application of NPK (600?mg.kg?1 of the N20:P10:K20 formulation), and a no fertilizer control were evaluated on growth and quality of chili pepper (Capsicum annuum var annuum) seedlings under greenhouse conditions with cool temperature of 15?±?3?°C. The results showed that most growth and quality traits were best improved by foliar application of Biomin aminochelate followed by Humifolin fertilizer. Higher values for leaf area, leaf number, chlorophyl index, root and shoot biomass, and leaf concentration of soluble sugars, N, K, Ca, and Zn, were attributed to foliar application of Biomin and Humifolin. The mixture of Biomin?+?Humifolin had reduced values of those parameters indicating possible negative interaction when these two organic fertilizers are mixed.  相似文献   

16.
Abstract

We studied the effects of the application of organic matter (OM) and chemical fertilizer (CF) on soil alkaline phosphatase (ALP) activity and ALP-harboring bacterial communities in the rhizosphere and bulk soil in an experimental lettuce field in Hokkaido, Japan. The ALP activity was higher in soils with OM than in soils with CF, and activity was higher in the rhizosphere for OM than in the bulk soil. Biomass P and available P in the soil were positively related to the ALP activity of the soil. As a result, the P concentration of lettuce was higher in OM soil than in CF soil. We analyzed the ALP-harboring bacterial communities using polymerase chain reaction based denaturing gradient gel electrophoresis (DGGE) on the ALP genes. Numerous ALP genes were detected in the DGGE profile, regardless of sampling time, fertilizer treatment or sampled soil area, which indicated a large diversity in ALP-harboring bacteria in the soil. Several ALP gene fragments were closely related to the ALP genes of Mesorhizobium loti and Pseudomonas fluorescens. The community structures of the ALP-harboring bacteria were assessed using principal component analysis of the DGGE profiles. Fertilizer treatment and sampled soil area significantly affected the community structures of ALP-harboring bacteria. As the DGGE bands contributing to the principal component were different from sampling time, it is suggested that the major bacteria harboring the ALP gene shifted. Furthermore, there was, in part, a significant correlation between ALP activity and the community structure of the ALP-harboring bacteria. These results raise the possibility that different ALP-harboring bacteria release different amounts and/or activity of ALP, and that the structure of ALP-harboring bacterial communities may play a major role in determining overall soil ALP activity.  相似文献   

17.
Because of the important role of soil organic carbon (SOC) in nutrient cycling and global climate changes, there has been an interest in understanding how different fertilizer practices affect the SOC preservation and promotion. The results from this study showed that long‐term application of manure (21 years) could increase significantly the content of SOC, total nitrogen (N) and soil pH in the red soil of southern China. The chemical structure of SOC was characterized by using solid‐state cross‐polarization magic angle spinning (CPMAS) 13C nuclear magnetic resonance (NMR) spectroscopy, and the aromatic C, ratio of alkyl C : O‐alkyl C, aromaticity and hydrophobicity of mineral fertilizers N, P and K plus organic manure (NPKM) and organic manure (M) treatments were less than those of mineral fertilizer nitrogen (N) and mineral fertilizers N, P and K (NPK) treatments. Both poorly crystalline (Feo) and organically complexed (Fep) iron contents were influenced significantly (P < 0.05) by different fertilizers, and it was observed that NPKM and M treatments increased the non‐crystalline Fe (Feo‐Fep) content. There was a significant (P < 0.01) positive correlation between soil organic C and non‐crystalline Fe in both the surface (0–20 cm) and subsurface (20–40 cm) soils. The results suggested that non‐crystalline Fe played an important role in the increase of SOC by long‐term application of organic manure (NPKM and M) in the red soil of southern China.  相似文献   

18.
Nitrogen (N) priming is a microbially mediated biochemical process as affected by different incorporation practices. However, little information is known about the microbial mechanisms driving the response of N priming to co-operation of Chinese milk vetch (CMV, Astragalus sinicus L.) and different rates of chemical fertilizers in paddy soils in South China. Here, an anaerobic incubation experiment was conducted to study N priming effects (PE) and their relationships with soil microbial functional genes after CMV incorporation alone (M), co-incorporation of CMV with 100% (normal dosage) chemical fertilizers (MC100), and co-incorporation of CMV with 80% chemical fertilizers (MC80). Co-incorporation of CMV and chemical fertilizers enhanced the short-time scale (the first 20 d of incubation) positive PE of N, while no significant differences existed among the three treatments on day 60 or 90 of incubation (P > 0.05). Compared with the M treatment, gross priming effect (GPE) in the MC100 and MC80 treatments significantly increased by 34.0% and 31.3%, respectively, and net priming effect (NPE) increased by 47.7% and 47.8%, respectively, during the first 20 d of incubation (P < 0.05). This was likely attributed to soil nutrient availability and added substrate quality. The MC100 and MC80 treatments increased the gdhA gene abundance by 5.0% and 9.8%, increased the gdh2 gene abundance by 12.7% and 45.7%, and increased the nasB gene abundance by 9.5% and 41.4%, respectively, in comparison with the M treatment on day 20 of incubation. Correlation analyses indicated that soil microbial functional genes involved in N mineralization (gdhA and gdh2), assimilatory nitrate reduction (nasB), and nitrification (amoB) were significantly correlated with N priming under different incorporation practices during the incubation period (P < 0.05). Thus, co-incorporation of CMV and chemical fertilizers can regulate soil microbial community functional gene structure, which may accelerate mineralization and assimilatory nitrate reduction and inhibit nitrification, thereby increasing the short-term positive PE of N in the present study.  相似文献   

19.
不同施肥措施对洞庭湖区旱地肥力及作物产量的影响   总被引：5，自引：0，他引：5  
应用长期定位试验方法,研究了洞庭湖区非粮食作物棉花-油菜轮作下,农民习惯施肥(TF)、配方施肥(NPK)及有机肥和化肥不同配比模式[有机肥来源氮占配方肥总氮量的50%(50%OM)、30%(30%OM)和10%(10%OM)]的作物产量和土壤养分的变化,以期为相应作物种植制度下的合理施肥提供参考。研究结果表明:在本试验施肥量及有机无机肥配比下,有机肥和化肥配施显著提高了棉花和油菜的产量,且以50%OM处理产量最高,各处理产量的顺序为50%OM30%OM10%OMNPKTFCK(不施肥对照);当有机氮施用量占总氮量的50%时(50%OM处理),棉花和油菜产量分别比NPK处理高24.52%、29.57%,比习惯施肥(TF)处理分别高46.03%和49.07%。同时,施用有机肥各处理作物产量的年际变化均不到20%,明显小于NPK、TF和CK处理,即施用有机肥不仅能促进旱地作物高产,同时也能保证其稳产。有机肥与化肥配施能增加土壤有机质、全氮、碱解氮和速效钾含量,且以50%OM处理效果最好,与试验前比较的增加幅度分别达57.5%、38.2%、65.1%和48.1%;土壤有效磷含量有随施入磷素量的增加而增加趋势;而CK处理土壤有机质和养分含量则均呈逐年下降的趋势。各处理土壤有机质和养分含量(Y)随试验年限(X)的变化均可用方程式Y=a X+b来表示。在洞庭湖区肥力较高的旱地土壤中,合理的有机肥和化肥施用比例对保障非粮作物高产稳产和耕地地力提升尤为重要,且本试验条件下当有机肥来源氮占总施氮量的50%时能获得最佳效果。  相似文献   

20.
To avoid environmental pollution due to excessive use of inorganic fertilizers, it is essential to increase the availability of nutrients using environmentally friendly resources, such as composts and clinoptilolite zeolite, in soil fertility management. In this study, an attempt was made to use different rates of inorganic fertilizers, compost, and clinoptilolite zeolite to correct the ongoing excessive use of inorganic fertilizers. A pot study using maize (Zea mays L.) as a test crop was carried out to determine the effects of amending inorganic fertilizers with compost and clinoptilolite zeolite on: (i) selected soil chemical properties, and (ii) N, P, and K uptake and use efficiency in maize cultivation. The pot study was conducted for 45 days (tasseling stage of maize). Amending inorganic fertilizers with compost and clinoptilolite zeolite increased soil total N, exchangeable Ca, Mg, K, and available P. Furthermore, P and K uptake and use efficiency of maize were significantly improved upon amending inorganic fertilizers with compost and clinoptilolite zeolite. Soil chemical properties and productivity of maize on acid soils can be improved through co-application of compost and clinoptilolite zeolite. However, field application of the authors’ findings is being evaluated in an on-going field experiment.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号