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: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:The mechanisms of acclimating to a nitrogen-fluctuating environment are necessary for the survival of aquatic cyanobacteria in their natural habitats, but our understanding is still far from complete. Here, the synthesis of phycobiliprotein is confirmed to be much earlier than that of photosystem components during recovery from nitrogen chlorosis and an unknown protein Ssr1698 is discovered to be involved in this synthetic process. The unknown protein is further identified as a c-type heme oxygenase (cHO) in tetrapyrrole biosynthetic pathway and catalyzes the opening of heme ring to form biliverdin IXα, which is required for phycobilin production and ensuing phycobiliprotein synthesis. In addition, the cHO-dependent phycobiliprotein is found to be vital for the growth of cyanobacterial cells during chlorosis and regreening through its nitrogen-storage and light-harvesting functions, respectively. Collectively, the cHO expressed preferentially during recovery from nitrogen chlorosis is identified in photosynthetic organisms and the dual function of this enzyme-dependent phycobiliprotein is proposed to be an important mechanism for acclimation of aquatic cyanobacteria to a nitrogen-fluctuating environment.
Project description:Purpose: To understand the effects of two different chemical forms of iron fertilizer on cadmium accumulation Methods:Cultivation and treatment for three weeks of dwarf Polish wheat seedlings by hydroponics, in triplicate, qRT–PCR validation was performed using TaqMan and SYBR Green assays Results: Iron fertilizer can effectively reduce cadmium concentration in plants Conclusions: Our study represents the different chemical forms of iron fertilizer have different mitigation effects on cadmium. The transcriptome gata showed that iron fertilizer have changed the cadimium metabolism
Project description:Cyanobacteria Prochlorococcus marinus subsp. pastoris str. CCMP1986 (MED4) and Prochlorococcus marinus str. MIT 9313 (MIT9313) are oceanic oxygenic phototrophs, where MED4 is abundant in surface waters (~0-50 meters) and MIT9313 is abundant at depths of ~100 meters. To explore nitrogen-regulated changes in gene expression in these Prochlorococcus ecotypes, log phase cultures of MED4 and MIT9313 were transferred to either nitrogen-replete (800 uM ammonium) or medium lacking supplemental nitrogen. Samples were taken over a time series in order to characterize changes in physiology and gene expression during increasing nitrogen starvation. The two ecotypes' molecular responses to different nitrogen sources were also assessed by comparing gene expression of log phase cultures growing in ammonium vs. urea and cyanate (MED4), and vs. urea and nitrite (MIT9313).
Project description:Thioredoxins play an essential role in regulating enzyme activity upon response to environmental changes, especially in photosynthetic organisms. These are crucial for the regulation of metabolism in cyanobacteria, but the key central processes redox-regulated remain to be determined. Physiological, metabolic and transcriptomic characterization of a conditional mutant of the essential trxA gene in Synechocystis (STXA2) revealed that reduced TrxA levels alter cell morphology and enter in a dormant-like state. TrxA depletion in the STXA2 strain inhibited protein synthesis and led to changes in amino acid pools and nitrogen/carbon reserve polymers, accompanied by oxidation of the Elongation Factor EF-Tu. Transcriptomic analysis of TrxA depletion in STXA2 showed a robust transcriptional response. Genes that responded negatively were grouped in a large cluster and were directly related to photosynthesis, ATP synthesis and CO2 fixation, while genes that responded positively were grouped in different clusters and related to respiratory electron transport, carotenoids synthesis, amino acid metabolism and protein degradation, among others. Regulation of cyanobacterial metabolism is complex and fine-tuned, our results link TrxA to the switch from anabolic to maintenance metabolism in cyanobacteria, regulating carbon and nitrogen balance.
Project description:Glutamine synthetase (GS), a key enzyme in biological nitrogen assimilation, is regulated in multiple ways in response to varying nitrogen sources and levels. Here we show a small regulatory RNA, NsiR4 (nitrogen stress induced RNA 4), which plays an important role in the regulation of GS in cyanobacteria. NsiR4 expression in the unicellular Synechocystis sp. PCC 6803 and in the filamentous, nitrogen-fixing Anabaena sp. PCC 7120 is stimulated through nitrogen-limitation via NtcA, the global transcriptional regulator of genes involved in nitrogen metabolism. NsiR4 is widely conserved throughout the cyanobacterial phylum, suggesting a conserved function. In silico target prediction, transcriptome profiling upon pulse overexpression and site-directed mutagenesis experiments using a heterologous reporter system showed that NsiR4 interacts with the 5’UTR of gifA mRNA, which encodes glutamine synthetase inactivating factor IF7. In Synechocystis, we observed an inverse relationship between the levels of NsiR4 and the accumulation of IF7 in vivo. This NsiR4-dependent modulation of gifA (IF7) mRNA accumulation influenced the glutamine pool and thus NH4+ assimilation via glutamine synthetase. As a second target, we identified ssr1528, a hitherto uncharacterized nitrogen-regulated gene. Competition experiments between wild type and an NsiR4 knock-out mutant showed that the lack of NsiR4 led to decreased acclimation capabilities of Synechocystis towards oscillating nitrogen levels. These results suggest a role for NsiR4 in the regulation of nitrogen metabolism in cyanobacteria, especially for the adaptation to rapid changes in available nitrogen sources and concentrations. NsiR4 is the first identified bacterial sRNA regulating the primary assimilation of a macronutrient.
Project description:Wheat (Triticum aestivum), one of the most important cereal crops, it provides many kinds of food for humans and animals, in this study, we performed the first comprehensive phosphoproteome analysis to study the regulatory mechanism of bread quality formation under different nitrogen fertilizer. Totally, 2470 phosphotides, represented 1372 proteins were identified in our study. and 411 proteins showed significant differences.
Project description:As an essential primary producer, cyanobacteria play an important role in the global cycle for both carbon and nitrogen in the ecosystems. Though the influence of nanoplastics on the carbon metabolism of cyanobacteria, especial Microcystis aeruginosa, a dominant species causing cyanobacterial blooms, is well studied, little is known about nanoplastics affecting the nitrogen metabolism.