Cellular and gene expression patterns associated with root bifurcation in Selaginella
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ABSTRACT: To identify possible molecular mechanisms with a role in root branching initiation in S. moellendorffii, we employed the developmental root branching assay for an RNA-seq experiment and sampled root tips on each day from 0 to 5 d after the first branching (time point 0), in which 300 µm apical parts were sampled to enrich for the meristematic region, while non-meristematic root regions were sampled separately
Project description:The root apical meristems (RAM) is established during embryogenesis and serves as a source of stem cells for plant growth and organogenesis. Young roots have a simple structure and meristeamtic and non-meristematic cells can be differentiated based on their location. We have used the Affymetrix Medicago Genome Array GeneChip to compare tissue from the root meristem and non-meristematic tissue to identify meristem specific candidate genes based on changes in gene expression before and after differentiation Experiment Overall Design: Roots were sectioned separating meristematic (root-tip) and non-meristematic root tissue; total RNA was extracted and used for hybridization to Affymetrix arrays
Project description:Paired-end RNA-Seq libraries were constructed for three root sections of the roots of barley cv. Clipper, and landrace Sahara, grown under control and salt-treated (100 mM NaCl) conditions on agar plates in quadruplicate. Experiments were conducted in a temperature-controlled growth cabinet at 17 C in the dark. After three days of germination, seminal roots were dissected according to the following steps: A 1.5 mm long section marked Zone 1 (meristematic zone) was taken from the root tip. A second section (Zone 2) was dissected from the elongation zone up to a third section, Zone 3 (maturation zone), which was excised at the point of visible root hair elongation up to 34 of the entire root. Four biological replicates were generated for each sample in four separate experiments totaling 48 samples. All RNA-seq libraries were constructed and paired-end sequenced (100 bp) on an Illumina HiSeq 2000 system at the Australian Genome Research Facility (Melbourne, Australia).
Project description:Despite the major physiological dissimilarities between roots and their tips, differences in their gene expression profiles remain largely unexplored. In this research, the transcriptome of rice (Oryza sativa L. subsp. Japonica) mature root tissue and root tips was monitored using mRNA-Seq at 2 time points. Almost 50 million 76 bp reads were mapped onto the rice genome sequence, differential expression patterns between tissues and time points were investigated and at least 1,006 novel transcriptionally active regions (nTARs) were detected to be expressed in rice root tissue. More than 30,000 genes were found to be expressed in rice roots, among which 1,761 root-specific and 306 tip-specific transcripts. Mature root tissue appears to respond more strongly to external stimuli than tips, showing a higher expression of for instance auxin responsive and ABA-responsive genes, as well as the phenylpropanoid pathway and photosynthesis upon light. The root tip-specific transcripts are mainly involved in mitochondrial electron transport, organelle development, secondary metabolism, DNA replication and metabolism, translation, and cellular component organization. As roots developed, genes involved in electron transport, response to oxidative stress, protein phosphorylation and metabolic processes were activated. For some nTARs a potential role in root development can be put forward based on homology to genes involved in CLAVATA signaling, cell cycle regulators and hormone signaling. A subset of differentially expressed genes and novel transcripts was confirmed using (q)RT-PCR. These results uncover previously unrecognized tissue-specific expression profiles and provide an interesting starting point to study the different regulation of transcribed regions of these tissues. 2 biological replicates of roots and 3 biological replicates of root tips were sampled at two time points (1 biological replicate contains pooled tissue from 6 plants)
Project description:In this study a comparison was made between the local transcriptional changes at two time points upon root knot (Meloidogyne graminicola) and migratory nematode (Hirschmanniella oryzae) infection in rice. Using mRNA-Seq we have characterized specific and general responses of the root challenged with these endoparastic root nematodes with very different modes of action. Root knot nematodes induce major developmental reprogramming of the root tip, where they force the cortical cells to form multinucleate giant cells, resulting in gall-development. Our results show that root knot nematodes force the plant to produce and transfer nutrients, like sugars and amino acids, to this tissue. Migratory nematodes, on the other hand, induce the expression of proteins involved in plant death and oxidative stress, and obstruct the normal metabolic activity of the root. While migratory nematode infection also causes upregulation of biotic stress-related genes early in the infection, the root knot nematodes seem to actively suppress the local defence of the plant root. This is exemplified by a downregulation of genes involved in the salicylic acid and ethylene pathways. Interestingly, hormone pathways usually involved in plant development, were strongly induced (auxin and gibberellin) or repressed (cytokinin) in the galls. In addition, thousands of novel transcriptionally active regions as well as highly expressed nematode transcripts were detected in the infected root tissues. These results uncover previously unrecognized nematode-specific expression profiles and provide an interesting starting point to study the physiological function of many yet unannotated transcripts potentially targeted by these nematodes. 2 or 3 biological replicates of nematode infected roots and root tips and their respective controls were sampled at two time points (1 biological replicate contains pooled tissue from 6 plants)
Project description:we used soybean genome chips to investigate the expression pattern of about 37,500 unique ESTs locating on soybean Affymetrix chips (Affymetrix Inc.). KEYWORDS: Tissue comparison we compared soybean root meristem samples with non-meristematic tissues in 10 days old vegetative stage seedlings to define a unique set of root meristem enriched genes.
Project description:We isolated the meristematic and elongation zones of Col-0, upb1-1 mutant and 35S::UPB1-3YFP/upb1-1 plants by micro-dissection and extracted RNA from each section independently. To identify genes that might mediate UPB1 function we conducted a series of microarray experiments. The spatial distribution of the UPB1 protein suggested that it might exert a different effect on gene expression in the meristematic and elongation zones. Therefore, we isolated the meristematic and elongation zones by micro-dissection and extracted RNA from each section independently. Total RNA was isolated from approximately 60 meristem- and elongation zones of Col-0, upb1-1 and 35S::UPB1-3YFP #2 6 day old plants. Two biological replicates were performed for each experiment.
Project description:To transcriptionally characterize lateral root development in rice, we subjected the rice LRIS to genome-wide transcript profiling via RNA-sequencing. Taking into account the appearance of the first (stage I primordium) cell divisions starting from 6 hours after NAA treatment, we sampled at 2 hours and at 5 hours after NAA treatment to capture the primary auxin response and the gene expression related to initiation, respectively. Additionally, we sampled at 8 hours, 14 hours and 20 hours, in which the root was highly enriched for stage I, II and III primordia, respectively. As the spatiotemporal assessment of the primordia in the LRIS showed a highly synchronous induction and development of lateral roots in particular in the region just above the root meristem, root sections between 750 µm and 2000 µm from the root tip were microdissected and used for RNA-extraction. To assess possible artefacts induced by the replacement of the medium, we sampled a control before and 2 hours after replacement with NPA containing medium.
Project description:The experiment aims to identify the response of mature nodules and denodulated roots of Medicago truncatula /Sinorhizobium medicae md4 to the systemic signaling of plant N deficit. The root systems of nodulated symbiotic plants were divided into two compartments. The N source of N2 fixing plants was exclusively the air. To reduce the plant nitrogen (N) supply (N-deficient conditions), we flushed one half root system with Ar/O2 (80/20 v/v) while the other half root system was kept on control conditions (Air). To characterize the systemic responses of the transcriptome to plant N deficit , nodules and roots of the non-treated half root system were harvested and total RNA isolated for RNAseq analysis. We performed a time-course (6 hours, 1-, 3- and 5-days treatment).
Project description:The effects of mercury (HgCl2) on barley (Hordeum vulgare L.) growth, physiological traits and gene expression profiles were studied. The shoot to root ratio was decreased in the two levels of HgCl2 (500 and 1000 ?M) assayed, which was related primarily with decreases in shoot dry weight. Moreover stomatal conductance was limited and leaf carbon isotope discrimination decreased. Therefore water uptake limitations seem to be an important component of barley responses to HgCl2. Evidences for decreased stomatal conductance and water uptake limitations were further confirmed by the over expression of ABA related transcripts and down regulation of an aquaporin in roots. Root dry weight was only affected at 1000 ?M HgCl2 and root browning was observed, while several transcripts for lignin biosynthesis were up regulated in HgCl2. Microarray analysis further revealed that growth inhibition in HgCl2 was related to increased expression of genes participating in ethylene biosynthesis and down regulation of several genes participating in DNA synthesis, chromatin structure and cell division, cell wall degradation and modification, oxidative pentose phosphate cycle and nitrogen metabolism pathway. Genes involved in detoxification and defence mechanisms were up regulated including several cytochrome P450s, glucosyltransferases and glutathione-s-transferases and amino acid metabolism participatory genes. It is concluded that barley plants survive in the presence of HgCl2 through several mechanisms that include water uptake limitations, shoot and root growth regulation, increased expression of genes involved in the biosynthesis of several plant protection secondary metabolites and finally through detoxification. Six samples were analysed including 3 biological replicates of mercury exposed roots and 3 controls (no mercury added to the growing solution)
Project description:Illumina HiSeq technology was used to generate mRNA profiles from Amanita muscaria ectomycorrhizal root tips compared to free-living mycelium . Ectomycorrhizal root tips and control mycelium were harvested after 6 weeks and used for RNA extraction. Reads of 150 bp were generated and aligned to Amanita muscaria transcripts (http://genome.jgi-psf.org/Amamu1) using CLC Genomics Workbench 7. mRNA profiles from Amanita muscaria ectomycorrhizal root tips and free-living mycelium were generated by Illumina HiSeq2000 sequencing (150bp). Two biological replicates were sequenced for mycorrhizal and mycelium samples.