Project description:Purpose: Zinc deficiency (ZnD) and iron deficiency (FeD), excess Zn (ZnE) and cadmium exposure (CdE) are major environmental problems for crop cultivation. Methods: Applying Tag-Seq technology to leaves of Brassica rapa grown under FeD, ZnD, ZnE or CdE conditions, with normal conditions as a control, we examined global gene expression changes and compared the expression patterns of multiple paralogs. Results: We identified 812, 543, 331 and 447 differentially expressed genes under FeD, ZnD, ZnE and CdE conditions, respectively, in B. rapa leaves.Further analysis revealed that genes associated with Zn, Fe and Cd responses tended to be over-retained in the B. rapa genome. Most of these multiple-copy genes showed the same direction of expression change under stress conditions. Conclusion: We conclude that the duplicated genes involved in trace element responses in B. rapa are functionally redundant, making the regulatory network more complex in B. rapa than in Arabidopsis thaliana. In total, there were 15 Digital gene expression libraries, one for each of the three replicates under the four trace metal element treatments and normal nutrient supply conditions as a control.
Project description:To identify more targets in soybean, particularly specific targets of Cd-stress-responsive miRNAs, high-throughput degradome sequencing was used. In total, we obtained 8913111 raw reads from the library which was constructed from a mixture of four samples (HX3-CK, HX3-Cd-treatment, ZH24-CK and ZH24-Cd-treatment). After removing the reads without the CAGAG adaptor, 5430126 unique raw-reads were obtained. The unique sequences were aligned to the G. max genome database, and 6516276 reads were mapped to the genome. The mapped reads from the libraries represented 51481 annotated G. max genes. Identification of miRNA targerts in soybean roots
Project description:Anti-epileptogenic agents that prevent the development of epilepsy following a brain insult remain the holy grail of epilepsy therapeutics. In order to identify such drugs, it is necessary to first understand the cellular and molecular events that underlie the epileptogenic process, from initial insult to the onset of spontaneous recurrent seizures. We have employed a label-free proteomic approach that allows quantification of large numbers of brain-expressed proteins in a single analysis in the well-established kainate (KA) mouse (C57BL/6J) model of epileptogenesis. In addition, we have incorporated two putative antiepileptogenic drugs, PSD95BP and 1400W, to give an insight into how such agents might ameliorate the epileptogenesis. The test drugs were administered at appropriate time-points after induction of status epilepticus (SE) and animals were euthanized at 7 days, their hippocampi removed, and subjected to LC-MS/MS analysis. A total of 2,579 proteins were identified; their normalized abundance was compared between treatment groups using ANOVA, with correction for multiple testing by false discovery rate. Significantly altered proteins were subjected to gene ontology analysis to look for enrichment of specific biological processes. KA-induced SE was most robustly associated with an increase in proteins involved in neuroinflammation, oxidative stress, cell-cell interactions and synaptic plasticity. Treatment with PSD95BP (Tat-NR2B9c) or an iNOS inhibitor, 1400W modulated several of these proteins. Our observations require validation in a larger-scale investigation, with candidate proteins explored in more detail. Nevertheless, this study has identified several mechanisms by which epilepsy might be developed and several targets for novel drug development.
Project description:Although urea is the most used nitrogen fertilizer worldwide, little is known on the capacity of crop plants to use urea per se as a nitrogen source for development and growth. To date, the molecular and physiological bases of its transport have been investigated only in a limited number of species. In particular, up to date only one study reported the transcriptomic modulation induced by urea treatment in the model plant Arabidopsis (Mérigout et al., 2008 doi: 10.1104/pp.108.119339). In maize, one of crops using huge amount of urea, only a physiological characterization of uptake and assimilation of the N-source has been conducted. General aim of the present work was the comprehension of the molecular basis of urea uptake and assimilation in maize plants, using a transcriptomic approach. In addition, the work focused on the possible interactions between the two main N-sources, conceivably occurring concomitantly in the soil, urea and nitrate. 5 dd-old maize plants were treated for 8 hours with nutrient solution containing nitrogen in form of urea; nitrate; urea and nitrate; or not exposed to any form of nitrogen. Three different biological replicates were used for each sample repeating the experiment three times. All samples were obtained pooling roots of six plants.
Project description:Plant cells contain different O-acetylserine(thiol)lyase (OASTL) enzymes involved in Cys biosynthesis and located in different subcellular compartments. These enzymes are made up of a complex variety of isoforms resulting in different subcellular Cys pools. To unravel the contribution of cytosolic Cys to plant metabolism, we characterized the knockout oas-a1.1 and osa-a1.2 mutants, deficient in the most abundant cytosolic OASTL isoform in Arabidposis thaliana. Total intracellular Cys and glutathione concentrations were reduced, and the glutathione redox state was shifted in favour of its oxidized form. Interestingly, the capability of the mutants to chelate heavy metals did not differ from that of the wild type, but the mutants have an enhanced sensitivity to Cd. With the aim of establishing the metabolic network most influenced by the cytosolic Cys pool, we used the ATH1 GeneChip for evaluation of differentially expressed genes in the oas-a1.1 mutant grown under non-stress conditions. The transcriptomic footprints of mutant plants had predicted functions associated with various physiological responses that are dependent on reactive oxygen species and suggested that the mutant was oxidatively stressed. To further elucidate the specific function(s) of the OAS-A1 isoform in the adaptation response to cadmium we extended the trasncriptome experiment to the wild type and oas-a1.1 mutant plants exposed to Cd. The comparison of transcriptomic profiles showed a higher proportion of genes with altered expression in the mutant than in the wild type, highlighting up-regulated genes identified as of the general oxidative stress response rather than metal-responsive genes. Wild type and oas-a1.1 mutant plants were grown hydroponically and, after a two-week acclimation period, the roots and shoots were harvested separately. Total RNA was then prepared and analyzed using the Affymetrix-Arabidopsis ATH1GeneChip array. Three biological replicates were performed for each sample. We made two different comparisons to classify the differently expressed genes in the mutant plant: oas-a1.1 roots versus wild-type roots and oas-a1.1 shoots versus wild-type shoots. Hydroponically-grown wild type and oas-a1.1 mutant plants were further treated with 50µM CdCl2 and 18h-treated-roots and 24h-treated-shoots were harvested. Total RNA was then prepared and analyzed using the Affymetrix-Arabidopsis ATH1GeneChip array. Three biological replicates were performed for each sample. Different comparisons were performed as follows: 18h Cd-treated wild type roots versus untreated wild type roots; 24h Cd-treated wild type shoots versus untreated wild type shoots; 18h Cd-treated oas-a1.1 roots versus untreated oas-a1.1 roots; 24h Cd-treated oas-a1.1 shoots versus untreated oas-a1.1 shoots; 18h Cd-treated oas-a1.1 roots versus 18h Cd-treated wild type roots; 24h Cd-treated oas-a1.1 shoots versus 24h Cd-treated wild type shoots
Project description:This experiment was annotated by TAIR (http://arabidopsis.org). This experiment studies the response of gene expression in roots of 25-35 day old plants grown on hydroponics after 6, 48 and 96 hours of potassium starvation. RNA from roots was extracted after transfer to control (control) or potassium free nutrient solution respectively (starvation). Experimenter name = Julian Schroeder; Experimenter phone = 619-534-7759; Experimenter fax = 619-534-7108; Experimenter department = J Schroeder Laboratory; Experimenter institute = University of California-San Diego; Experimenter address = Biology Department; Experimenter address = University of California-San Diego; Experimenter address = La Jolla; Experimenter zip/postal_code = CA 92093-0116; Experimenter country = USA Experiment Overall Design: 4 samples were used in this experiment
Project description:Low phosphate concentrations are frequently a constraint for maize growth and development, and therefore, enormous quantities of phosphate fertilizer are expended in maize cultivation, which increases the cost of planting. Low phosphate stress not only increases root biomass but can also cause significant changes in root morphology. Low phosphate availability has been found to favor lateral root growth over primary root growth by dramatically reducing primary root length and increasing lateral root elongation and lateral root density in Arabdopsis. While in our assay when inbred line Q319 subjected to phosphate starvation, The numbers of lateral roots and lateral root primordia were decreased after 6 days of culture in a low phosphate solution (LP) compared to plants grown under normal conditions (sufficient phosphate, SP), and these differences were increased associated with the stress caused by phosphate starvation. However, the growth of primary roots appeared not to be sensitive to low phosphate levels. This is very different to Arabidopsis. To elucidate how low phosphate levels regulate root modifications, especially lateral root development, a transcriptomic analysis of the 1.0-1.5 cm lateral root primordium zone (LRZ) of maize Q319 treated after 2 and 8 days by low phosphate was completed respectively. The present work utilized an Arizona Maize Oligonucleotide array 46K version slides, which contained 46,000 maize 70-mer oligonucleotides designated by TIGR ID, and the sequence information is available at the website of the Maize Oligonucleotide Array Project as the search item representing the >30,000 identifiable unique maize genes (details at http://www.maizearray.org). Keywords: low phosphate, Lateral Root Primordium Zone, maize Two-condition experiment, low phosphate treated lateral root primordium zone of maize root vs. normal cultrued lateral root primordium zone. Biological replicates: 9 control, 9 treated, independently grown and harvested. One replicate per array.
Project description:Aluminum toxicity is one of the major limiting factors for many crops worldwide. The primary symptom of Al toxicity syndrome is the inhibition of root growth, leading to poor water and nutrient absorption. The causes of this inhibition are still elusive, with several biochemical pathways being affected and with a significant variation between species. Most of the work done so far to investigate the genes responsible for Al tolerance used hydroponic culture. Here we evaluated plant responses using soil as substrate, which is a condition closer to the field reality. We used Affymetrix chips to reveal the transcriptional changes of two maize genotypes contrasting for Al tolerance. Leaves from Cat100-6 (Al-tolerant) and S1587-17 (Al-sensitive) maize genotypes were harvested after growing on acid or control soil for 3 days. Total RNA was extracted and hybridized to Affymetrix GeneChip Maize Genome Array. Three biological replicates were used for each sample.
Project description:Maize is a globally important food and feed crop, and a low-phosphate (Pi) supply in the soil frequently limits maize yield in many areas. MicroRNAs (miRNAs) play important roles in the development and adaptation of plants to the environment. In this study, the spatio-temporal miRNA transcript profiling of the maize inbred line Q319 root and leaf in response to low Pi was analyzed with high-throughput sequencing technologies, and the expression patterns of certain target genes were detected by real-time RT-PCR. Complex small RNA populations were detected after low-Pi culture and displayed different patterns in the root and leaf. miRNAs identified as responding to Pi deficiency can be grouped into ‘early’ miRNAs that respond rapidly, and often non-specifically, to Pi deficiency, and ‘late’ miRNAs that alter the morphology, physiology or metabolism of plants upon prolonged Pi deficiency. The miR827-Nitrogen limitation adaptation (NLA)-mediated post-transcriptional pathway was conserved in response to Pi availability of maize, but the miR399-mediated post-transcriptional pathway was different from Arabidopsis. Abiotic stress-related miRNAs engaged in interactions of different signaling and/or metabolic pathways. Auxin-related miRNAs (zma-miR393, zma-miR160a/b/c, zma-miR160d/e/g, zma-miR167a/b/c/d and zma-miR164a/b/c/d/g) and their targets play important roles in promoting primary root growth, inhibiting lateral root development and retarding upland growth of maize when subjected to low Pi. The changes in expression of miRNAs and their target genes suggest that the miRNA regulation/alterations compose an important mechanism in the adaptation of maize to a low-Pi environment; certain miRNAs participate in root architecture modification via the regulation of auxin signaling. A complex regulatory mechanism of miRNAs in response to a low-Pi environment exists in maize, revealing obvious differences from that in Arabidopsis. Maize (Zea mays L.) inbred line Q319 was used in this study. Seeds of the maize inbred line Q319 were surface sterilized and held at 28°C in darkness. Seedlings (4 days old) were transferred to a sufficient phosphate (SP, 1,000 μM KH2PO4) solution (Ca(NO3)2.4H2O 2 mM, NH4NO3 1.25 mM, KCl 0.1 mM, K2SO4 0.65 mM, MgSO4 0.65 mM, H3BO3 10.0 mM, (NH4)6Mo7O24 0.5 mM, MnSO4 1.0 mM, CuSO4.5H2O 0.1 mM, ZnSO4.7H2O 1.0 mM, Fe-EDTA 0.1 mM), allowed to grow for 4 days (plants with 2–3 leaves). After 2-3 days of re-culturing in SP nutrient solutions, half of the seedlings were transplanted into a low phosphate (LP, same composition as the SP solution, except that 5 μM KH2PO4 and 1 mM KH2PO4 were replaced with 1 mM KCl) nutrient solution. The plants were grown under a 32°C/25°C (day/night) temperature regime at a photon flux density (PFD) of 700 μmol m-2 s-1 with a 14 h/10 h light/dark cycle in a greenhouse with approximately 65% relative humidity. The roots and leaves were then harvested at 0, 1, 2, 4, 8 days and 8 days and cultured in SP solution (as a normal growth control) for small RNA analysis. The samples were frozen in liquid nitrogen immediately and stored at -80℃ for further analysis. Each biological repeat contains segments from 15~20 plants. Total RNA was extracted as previously described in Molecular Cloning (Sambrook and Russell David, 1989) and was then subjected to two additional chloroform washes prior to nucleic acid precipitation. The small RNA digitalization analysis based on HiSeq high-throughput sequencing takes the SBS-sequencing by synthesis. Then the 50nt sequence tags from HiSeq sequencing will go through the data cleaning first, which includes getting rid of the low quality tags and several kinds of contaminants from the 50nt tags. Length distribution of clean tags are then summarized. Afterwards, the standard bioinformatics analysis will annotate the clean tags into different categories and take those which can not be annotated to any category to predict the novel miRNA and base edit of potential known miRNA. Compare the known miRNA expression between two samples to find out the differentially expressed miRNA. The procedures are shown as below: (1)Normalize the expression of miRNA in two samples (control and treatment) to get the expression of transcript per million (TPM). Normalization formula: Normalized expression = Actual miRNA count/Total count of clean reads*1000000 (2)Calculate fold-change and P-value from the normalized expression. Then generate the log2ratio plot and scatter plot.