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.
Project description:Nitrogen is one of the essential elements for plant growth. NH4+ and NO3- are two major forms of absorbing element N for higher plants. In this study we found that the growth of Panax notoginseng is inhibited when only adding ammonium nitrogen fertilizer, and adding nitrate fertilizer can alleviate the toxicity caused by ammonium. We use RNA-seq to identify genes that are related to the alleviated phenotypes after introducing NO3- to Panax notoginseng roots under NH4+ stresses. Twelve RNA-seq profiles in four sample groups, i.e., control, samples treated with NH4+, samples treated with NO3- only, and treated with both NH4+ and NO3- were obtained and analyzed to identify deregulated genes in samples with different treatments. ACLA-3 gene is downregulated in NH4+ treated samples, but is upregulated in samples treated with NO3- and with both NH4+ and NO3-, which is further validated in another set of samples using qRT-PCR. Our results suggest that unbalanced metabolism of nitrogen and nitrogen is the main cause of ammonium poisoning in roots of Panax notoginseng, and NO3- may significantly upregulate the activity of ACLA-3 which subsequently enhances the citrate cycle and many other metabolic pathways in Panax notoginseng root. These potentially increase the integrity of the Panax notoginseng roots. Our results suggest that introducing NO3- fertilizer is an effective means to prevent the occurrence of toxic ammonium in Panax notoginseng root.
Project description:Algal biofuel production requires an input of synthetic nitrogen fertilizer. Fertilizer synthesized via the Haber-Bosch process produces CO2 as a waste by-product and represents a substantial financial and energy investment. Reliance on synthetic fertilizer attenuates the environmental significance and economic viability of algae production systems. To lower fertilizer input, the waste streams of algal production systems can be recycled to provide alternative sources of nitrogen such as amino acids to the algae. The halophytic green alga Dunaliella viridis can use ammonium (NH4+) derived from the abiotic degradation of amino acids, and previously, supplementation of NH4+ from glutamine (GLN) degradation was shown to support acceptable levels of growth and increased neutral lipid production compared to nitrate. To understand the effect of glutamine-released NH4+ on algae growth and physiology, metabolite levels, growth parameters, and transcript profiles of D. viridis cultures were observed in a time course after transition from media containing nitrate as a sole N source to medium containing GLN, glutamate (GLU), or a N-depleted medium. Growth parameters were similar between GLN (NH4+) and nitrate supplemented cultures, however, metabolite data showed that the GLN supplemented cultures (NH4+) more closely resembled cultures under nitrogen starvation (N-depleted and GLU supplementation). Neutral lipid accumulation was the same in nitrate and glutamine-derived NH4+ cultures. However, glutamine-derived NH4+ caused a transcriptional response in the immediate hours after inoculation of the culture. The strong initial response of cultures to NH4+ changed over the course of days to closely resemble that of nitrogen starvation. These observations suggest that release of NH4+ from glutamine was sufficient to maintain growth, but not high enough to trigger a cell transition to a nitrogen replete state. Comparative transcript profiling of the nitrogen-starved and nitrate-supplied cultures show an overall downregulation of fatty acid synthesis and a shift to starch synthesis and accumulation. The results indicate that a continuous, amino acid derived slow release of NH4+ to algae cultures could reduce the amount of synthetic nitrogen needed for growth, but optimization is needed to balance nitrogen starvation and cell division.
Project description:The environment plays important role in the interaction between plant hosts and pathogens. The application of chemical fertilizer is a crucial breeding technology to enhance crop yield since last century. As the most abundant fertilizer, nitrogen often increases disease susceptibility for crop plants. The underlying mechanism for nitrogen induced disease susceptibility is elusive. Here we found that nitrogen application activate gibberellin signaling by degradation of SLR1, the repressor protein in gibberellin signaling, which result in simultaneously promoting plant growth and disease susceptibility. SLR1, physically interacts with OsNPR1 and consequently facilitate OsNPR1 mediated defense responses. Transcriptome analysis showed that OsNPR1-SLR1 module plays a vital role in transcriptional reprogramming for both disease resistance and plant growth. Increase of SLR1 protein level in gibberellin deficient rice plants neutralizes disease susceptibility but sacrifice yield enhancement under high nitrogen supply. Mutation in SD1, encoding OsGA2ox2, produced more grains than WT,and maintains disease resistance under high nitrogen supply. Taken together, our work reveals the molecular mechanism underlying nitrogen-induced disease susceptibility, and demonstrates that the application of sd1 rice varieties prevent the tradeoff between disease susceptibility and yield increase under high nitrogen supply.
Project description:Gene expression was investigated in response to nitrogen fertilizer in developing grains of field grown barley (Hordeum vulgare L. cv. Barke) at four different time points: 10, 15, 18 and 25 days after pollination (DAP).
Project description:Two groups of plants were nodulated with Sinorhizobium medicae or S. meliloti; the third group grew in a rhizobia-free medium and received mineral nitrogen fertilizer. In addition to growth analyses, physiological and molecular responses of the two systems were assessed using ionomic, metabolomic and proteomic techniques.
2022-02-24 | PXD002162 | Pride
Project description:16s RNA from tobacco plantations in biochar fertilizer treatment
Project description:Among the mineral elements necessary for plant growth, nitrogen (N) is the macronutrient required in larger amounts. The optimization of N use efficiency (NUE) in maize could be obtained through both genetic improvement and agronomic practices in order to enhance production and reduce the negative impact of the N fertilizer use on the environment. Physiological characterizations of inbred lines with different NUE are available in maize.
Project description:To determine whether and how warming affects the functional capacities of the active microbial communities, GeoChip 5.0 microarray was used. Briefly, four fractions of each 13C-straw sample were selected and regarded as representative for the active bacterial community if 16S rRNA genes of the corresponding 12C-straw samples at the same density fraction were close to zero.