Project description:Intercropping is a vital technology in resource-limited agricultural systems with low inputs. Peanut/maize intercropping enhances iron (Fe) nutrition in calcareous soil. Proteomic studies of the differences in peanut leaves, maize leaves and maize roots between intercropping and monocropping systems indicated that peanut/maize intercropping not only improves Fe availability in the rhizosphere but also influences the levels of proteins related to carbon and nitrogen metabolism. Moreover, intercropping may enhance stress resistance in the peanut plant (Xiong et al. 2013b). Although the mechanism and molecular ecological significance of peanut/maize intercropping have been investigated, little is known about the genes and/or gene products in peanut and maize roots that mediate the benefits of intercropping. In the present study, we investigated the transcriptomes of maize roots grown in intercropping and monocropping systems by microarray analysis. The results enabled exploration differentially expressed genes in intercropped maize. Peanut (Arachis hypogaea L. cv. Luhua14) and maize (Zea mays L. cv. Nongda108) seeds were grown in calcareous sandy soil in a greenhouse. The soil was enhanced with basal fertilizers [composition (mg·kg−1 soil): N, 100 (Ca (NO3)2·4H2O); P, 150 (KH2PO4); K, 100 (KCl); Mg, 50 (MgSO4·7H2O); Cu, 5 (CuSO4·5H2O); and Zn, 5 (ZnSO4·7H2O)]. The experiment consisted of three cropping treatments: peanut monocropping, maize monocropping and intercropping of peanut and maize. After germination of peanut for 10 days, maize was sown. Maize samples were harvested after 63 days of growth of peanut plants based on the degree of Fe chlorosis in the leaves of monocropped peanut. The leaves of monocropped peanut plants exhibited symptoms of Fe-deficiency chlorosis at 63 days, while the leaves of peanut plants intercropped with maize maintained a green color.
Project description:Nitrogen (N), the primary limiting factor for plant growth and yield in agriculture, has a patchy distribution in soils due to fertilizer application or decomposing organic matter. Studies in solution culture over-simplify the complex soil environment where microbial competition and spatial and temporal heterogeneity challenge roots’ ability to acquire adequate amounts of nutrients required for plant growth. In this study, various ammonium treatments (as 15N) were applied to a discrete volume of soil containing tomato (Solanum lycopersicum) roots to simulate encounters with a localized enriched patch of soil. Transcriptome analysis was used to identify genes differentially expressed in roots 53 hrs after treatment. Results: The ammonium treatments resulted in significantly higher concentrations of both ammonium and nitrate in the patch soil. The plant roots and shoots exhibited increased levels of 15N over time, indicating a sustained response to the enriched environment. Root transcriptome analysis identified 585 genes differentially regulated 53 hrs after the treatments. Nitrogen metabolism and cell growth genes were induced by the high ammonium (65 ug NH4+-N g-1 soil), while stress response genes were repressed. The complex regulation of specific transporters following the ammonium pulse reflects a simultaneous and synergistic response to rapidly changing concentrations of both forms of inorganic N in the soil patch. Transcriptional analysis of the phosphate transporters demonstrates cross-talk between N and phosphate uptake pathways and suggests that roots increase phosphate uptake via the arbuscular mycorrhizal symbiosis in response to N. Conclusion: This work enhances our understanding of root function by providing a snapshot of the response of the tomato root transcriptome to a pulse of ammonium in a complex soil environment. This response includes an important role for the mycorrhizal symbiosis in the utilization of an N patch.
Project description:Two maize hybrid cultivars contrasting in low nitrogen tolerance (low nitrogen-tolerant XY335 and low nitrogen-sensitive HN178) were used in this study . The experiment was carried out at Xinji Experimental Station (43º31′N, 124º48′E) of Hebei Agricultural University. The top 0-20 cm of the soil used contained organic matter 17.79 g·kg-1, total nitrogen 1.21 g·kg-1, alkali hydrolyzed nitrogen 64.9 mg.kg-1, available phosphorus 23.8 mg·kg-1, and available potassium 120.6 mg·kg-1. The experiment adopted a split plot design, with varieties as the main plot and nitrogen fertilizer as the sub-plot. There were 2 varieties for testing: XY335 and HN138. Two levels of nitrogen supply: N0 (0 kg N ha-1) and N240 (240 kg N ha-1), replicated three times. Each plot had 6 rows, with the row length measuring 20 m, and the row spacing of 60 cm, giving the plot area of 72 m2. The planting density was 67,500 plants ha-1. Nitrogen fertilizer used was urea (46% N), and 50% was applied before sowing and at the flared stage, respectively. During the grain filling stage, leaf tissues of three biological replicates were collected from control and treatment conditions, and immediately frozen in liquid nitrogen for subsequent proteomics analysis.
2022-05-20 | PXD028027 | Pride
Project description:Peanut leaves and soil microorganisms
| PRJNA1131189 | ENA
Project description:Effect of nitrogen fertilizer application on soil C\N\P cycling microorganisms
Project description:Nitrogen availability in the soil is a major determinant of crop yield. While the application of fertilizer can substantially increase the yield on poor soils, it also causes nitrate pollution of water resources and high costs for farmers. Increasing the nitrogen use efficiency in crop plants is a necessary step to implement low input agricultural systems. We exploited the genetic diversity present in the world-wide Arabidopsis thaliana population to study adaptive growth patterns and changes in gene expression associated with chronic low nitrate stress, with the aim to identify biomarkers associated with good plant performance under low nitrate availability. Transcription and epigenetic factors were identified as important players in the adaptatiion to limited nitrogen in a global gene expression analysis using the Affymetrix ATH1 chip.
Project description:Arbuscular mycorrhizal (AM) fungi contribute to plant nutrient uptake in systems managed with reduced fertilizer inputs such as organic agriculture and natural ecosystems by extending the effective size of the rhizosphere and delivering mineral. Connecting the molecular study of the AM symbiosis with agriculturally- and ecologically-relevant field environments remains a challenge and is a largely unexplored research topic. This study utilized a cross-disciplinary approach to examine the transcriptional, metabolic, and physiological responses of tomato (Solanum lycopersicum) AM roots to a localized patch of nitrogen (N). A wild-type mycorrhizal tomato and a closely-related nonmycorrhizal mutant were grown at an organic farm in soil that contained an active AM extraradical hyphal network and soil microbe community. The majority of genes regulated by upon enrichment of nitrogen were similarly expressed in mycorrhizal and nonmycorrhizal roots, suggesting that the primary response to an enriched N patch is mediated by mycorrhiza-independent root processes. However where inorganic N concentrations in the soil were low, differential regulation of key tomato N transport and assimilation genes indicate a transcriptome shift towards mycorrhiza-mediated N uptake over direct root supplied N. Furthermore, two novel mycorrhizal-specific tomato ammonium transporters were also found to be regulated under low N conditions. A conceptual model is presented integrating the transcriptome response to low N and highlighting the mycorrhizal-specific ammonium transporters. These results enhance our understanding of the role of the AM symbiosis in sensing and response to an enriched N patch, and demonstrate that transcriptome analyses of complex plant-microbe-soil interactions provide a global snapshot of biological processes relevant to soil processes in organic agriculture.
Project description:<p>Biological nitrogen fixation by free-living bacteria and rhizobial symbiosis with legumes plays a key role in sustainable crop production. Here, we study how different crop combinations influence the interaction between peanut plants and their rhizosphere microbiota via metabolite deposition and functional responses of free-living and symbiotic nitrogen-fixing bacteria. Based on a long-term (8 year) diversified cropping field experiment, we find that peanut co-cultured with maize and oilseed rape lead to specific changes in peanut rhizosphere metabolite profiles and bacterial functions and nodulation. Flavonoids and coumarins accumulate due to the activation of phenylpropanoid biosynthesis pathways in peanuts. These changes enhance the growth and nitrogen fixation activity of free-living bacterial isolates, and root nodulation by symbiotic Bradyrhizobium isolates. Peanut plant root metabolites interact with Bradyrhizobium isolates contributing to initiate nodulation. Our findings demonstrate that tailored intercropping could be used to improve soil nitrogen availability through changes in the rhizosphere microbiome and its functions.</p>
Project description:Arbuscular mycorrhizal (AM) fungi contribute to plant nutrient uptake in systems managed with reduced fertilizer inputs such as organic agriculture and natural ecosystems by extending the effective size of the rhizosphere and delivering mineral. Connecting the molecular study of the AM symbiosis with agriculturally- and ecologically-relevant field environments remains a challenge and is a largely unexplored research topic. This study utilized a cross-disciplinary approach to examine the transcriptional, metabolic, and physiological responses of tomato (Solanum lycopersicum) AM roots to a localized patch of nitrogen (N). A wild-type mycorrhizal tomato and a closely-related nonmycorrhizal mutant were grown at an organic farm in soil that contained an active AM extraradical hyphal network and soil microbe community. The majority of genes regulated by upon enrichment of nitrogen were similarly expressed in mycorrhizal and nonmycorrhizal roots, suggesting that the primary response to an enriched N patch is mediated by mycorrhiza-independent root processes. However where inorganic N concentrations in the soil were low, differential regulation of key tomato N transport and assimilation genes indicate a transcriptome shift towards mycorrhiza-mediated N uptake over direct root supplied N. Furthermore, two novel mycorrhizal-specific tomato ammonium transporters were also found to be regulated under low N conditions. A conceptual model is presented integrating the transcriptome response to low N and highlighting the mycorrhizal-specific ammonium transporters. These results enhance our understanding of the role of the AM symbiosis in sensing and response to an enriched N patch, and demonstrate that transcriptome analyses of complex plant-microbe-soil interactions provide a global snapshot of biological processes relevant to soil processes in organic agriculture. 30 samples were analyzed. There were 2 genotypes (wildtype and mutant) and 3 treatments (two N treatments and a water control) for a total of 6 groups. Each group had 5 biological replicates.
Project description:Tomato seeds (Solanum lycopersicum Mill., cultivar Marion) were germinated in vermiculite and 10-day old seedlings were transplanted into 4-inch plastic pots containing a mixture of composted pine bark and vermiculite (3:1) amended with lime and fertilizer. Plants were incubated in a growth chamber (constant 30oC, 14-h photoperiod; 180 ?mol s-1 m-2 light intensity) for 18-21 days before inoculation. Seedlings received a complete liquid fertilizer approximately 7 and 14 days after transplanting. Unwounded roots were inoculated with R. solanacearum by drenching the soil in each pot with 40 ml of water containing 1´107 CFU ml-1 of the wild type or 1´108 CFU ml-1 of the hrp mutant. Non inoculated plants received 40 ml of water. Four days after inoculation, a piece of each stem from about 1-cm above the soil line to just below the cotyledon node was excised, immediately plunged into liquid nitrogen, and stored at -80oC. A separate 0.5-cm stem section from the cotyledon node was removed aseptically from each plant and the number of bacteria in the section determined by dilution plating. Stem pieces from plants systemically colonized by R. solanacearum were pulverized in a mortar under liquid nitrogen, and total RNA was extracted with the Tri-Reagent (Molecular Research Center) and then treated with RNase-free recombinant DNase (Ambion) according to the recommended protocols from TIGR and stored at -70oC. Keywords: Direct comparison