Arabidopsis regeneration from multiple tissues occurs via a root development pathway
Ontology highlight
ABSTRACT: Unlike most animal cells, plant cells can easily regenerate new tissues from a wide variety of organs when properly cultured. The common elements that provide varied plant cells with their remarkable regeneration ability are still largely unknown. Here we describe the initial process of Arabidopsis in vitro regeneration, where a pluripotent cell mass termed callus is induced. We demonstrate that callus resembles the tip of a root meristem, even if it is derived from aerial organs such as petals, which clearly shows that callus formation is not a simple reprogramming process backwards to an undifferentiated state as widely believed. Furthermore, callus formation in roots, cotyledons and petals is blocked in mutant plants incapable of lateral root initiation. It thus appears that the ectopic activation of a lateral root development program is a common mechanism in callus formation from multiple organs. Four sets of biologically independent tissue samples were collect for root, cotyledon and petal explants just after being excised from plants (d0) or after ten days on callus-inducing medium (CIM, d10). Samples derived from the same organ were co-hybridized in the array experiments. Dyes used for labeling the RNA populations derived from the individual samples were switched in the replicate experiments to reduce dye-related artefacts.
Project description:Plant inflorescence meristems and floral meristems possess specific boundary domains that result in floral organ separation, and in proper numbers of floral organs. HANABA TARANU (HAN) encodes a boundary-expressing GATA type zinc finger transcription factor that regulates shoot apical meristem organization, cell division and flower development in Arabidopsis, but the underlying mechanism remains unclear. Through time-course whole genome oligonucleotide microarray analyses following transient overexpression of HAN, we find that HAN represses hundreds of genes, especially genes involved in hormone responses and floral organ regulation. Transient overexpression of HAN also causes the repression of HAN itself and three other HAN family genes: HANL2 (HAN-LIKE2), GNC (GATA, NITRATE-INDUCIBLE, CARBON-METABOLISM-INVOLVED) and GNL (GNC LIKE), forming a negative regulatory feedback loop. Double- and triple-mutant strains of han with hanl2, gnc and gnl show synergistic effects on sepal fusion, petal number, and silique length, and embryo development, as well as carpelloid stamens. Transcripts of HANL2, GNC and GNL have similar accumulation patterns, specifically in petals, stamens, carpels and inflorescence meristems, which are partially overlapping with the expression pattern of HAN, suggesting that HAN and HAN family genes share redundant functions during flower development. We further show by yeast two hybrid assays that HAN can homodimerize as well as heterodimerize with other HAN family proteins. Chromatin-immunoprecipitation analyses indicate that HAN directly binds to its own promoter and the promoter of GNC in vivo. These findings, together with the fact that constitutive overexpression of HAN has an even stronger phenotype than a loss of function mutation, support the hypothesis that HAN may function as a key repressor that regulates floral development via intricate regulatory networks involving genes in the GATA3 family, hormone actions and floral organ specification. Time course induction experiment. Arabidopsis inflorescences containing flower buds from stages 1-9 were collected for microarray experiment 0h, 4h, 12h and 72h after 10M-BM-5M Dex treatment. RNA samples from mock- and Dex-treated plants at each time point were co-hybridized, and labeling dyes were swapped between replicates to reduce dye-related bias. Four biological replicates were used for the microarray hybridization.
Project description:Unlike most animal cells, plant cells can easily regenerate new tissues from a wide variety of organs when properly cultured. The common elements that provide varied plant cells with their remarkable regeneration ability are still largely unknown. Here we describe the initial process of Arabidopsis in vitro regeneration, where a pluripotent cell mass termed callus is induced. We demonstrate that callus resembles the tip of a root meristem, even if it is derived from aerial organs such as petals, which clearly shows that callus formation is not a simple reprogramming process backwards to an undifferentiated state as widely believed. Furthermore, callus formation in roots, cotyledons and petals is blocked in mutant plants incapable of lateral root initiation. It thus appears that the ectopic activation of a lateral root development program is a common mechanism in callus formation from multiple organs.
Project description:The composition of the transcriptome is regulated by both mRNA synthesis and degradation. One route for mRNA decay is through 5’ decapping, which can be initiated by decapping enzymes and small RNAs. Although decapped RNAs are an important intermediate for mRNA decay, their identity and abundance have never been studied on a large scale. Here we present an experimental method for transcriptome-wide profiling of decapped mRNAs. We applied the method to study the prevalence of decapped transcripts during the early stages of Arabidopsis thaliana flower development. Decapped transcripts were identified for the majority of expressed genes, although at different levels. By comparing decapped RNA levels with steady-state overall transcript levels, our study provides evidence for widespread decapping-mediated mRNA degradation control in numerous biological processes and for genes of varied molecular functions, implying that mRNA decapping is a dynamically regulated process. Sequence analyses identified structural features of transcripts and cis-elements that were associated with levels of decapping. Four sets of biologically independent tissue samples were collect 0,1,2,3,4, and 5 days after activation of the AP1-GR fusion protein. Decapped mRNA and total mRNA of each time point from each set were co-hybridized to micoarrays. Dyes used for labeling the RNA populations derived from the individual samples were switched in the replicate experiments to reduce dye-related artefacts.
Project description:First Douglas fir proteomes by nLC-MS/MS from 12 different organs : root, stem, xylem, needle, bud, female and male flowers, immature and mature seed, immature and mature somatic embryos and callus.
Project description:A pilot experiment for an RNA-seq dataset (SRP003234). This experiment compares AP1 domain-specific translating RNA with total flower translating mRNA. Two-condition experiment, AP1 flower domains vs. whole flower at flower stage 4.
Project description:Plant regeneration could be achieved via formation of a pluripotent cell mass termed callus, nature of which is a group of fast-dividing root primordium cells. However, mechanisms that strictly control the stem cell fate transition in regeneration of callus remain elusive. Here we show that the Arabidopsis ISWI type chromatin remodelers specifically promote the second-step cell fate transition from root founder cells to root primordium cells in the leaf-to-callus transition. Leaf explants cultured in CIM from Col-0 or chr11-1 chr17-1 at time 0 and 8 days after culture (8 DAC) were used for RNA preparation. Microarray was performed using the AffymetrixGeneChip system. Three independent experiments were performed.
Project description:This SuperSeries is composed of the following subset Series: GSE38358: Molecular basis for the specification of floral organs by APETALA3 and PISTILLATA (ChIP-Seq) GSE38362: Molecular basis for the specification of floral organs by APETALA3 and PISTILLATA (mRNA) Refer to individual Series
Project description:This experiment describes gene expression after the activation of APETALA1-GR, to study and identify AP1 target genes. We used a 35S:AP1-GR ap1 cal line to induce a synchronized response activating the AP1-GR fusion protein in ap1 cal inflorescence-like meristems through dexamethasone treatment. Tissue samples were collected immediately after the treatment, as well as subsequent timepoints. The expression profiles of the individual samples were then analyzed by gene expression profiling using whole-genome oligonucleotide arrays (non-commercial; Meyerowitz Lab Arabidopsis Operon Array v4). Keywords: time course Four sets of biologically independent tissue samples were collect at 0, 2, 4 ,8, and 12 hours after the application of dexamethasone (Dex-; activation of the AP1-GR fusion protein) or a mock solution (Mock-; control). In each of the biological replicates of the time course experiments, all the samples derived from dexamethasone (Dex)-treated plants were labeled with one dye (i.e., Cy3), and all the samples derived from the corresponding Mock-treated plants were labeled with the alternative dye (i.e., Cy5). The dyes used for labeling RNA from a given treatment type (Dex and Mock) were switched for two of the replicate experiments, to reduce dye-related artifacts. Dex- and Mock-derived samples for each timepoint and biological replicate were co-hybridized. This experimental setup resulted in a total of 5 hybridizations per set (0h, 2h, 4, 8h, and 12h; Dex vs. Mock at each timepoint), and two biological replicate sets labeled with each dye polarity (Mock-Cy3/Dex-Cy5, and vice versa). The combined ratio data results are available as a supplementary file on the Series record.
Project description:This experiment describes gene expression after the activation of APETALA1-GR, to study and identify AP1 target genes. We used a 35S:AP1-GR ap1 cal line to induce a synchronized response activating the AP1-GR fusion protein in ap1 cal inflorescence-like meristems through dexamethasone treatment. Tissue samples were collected immediately after the treatment, as well as subsequent timepoints. The expression profiles of the individual samples were then analyzed by gene expression profiling using whole-genome oligonucleotide arrays (non-commercial; Meyerowitz Lab Arabidopsis Operon Array v4). Keywords: time course Four sets of biologically independent tissue samples were collect at 0, 2, 4 ,8, and 12 hours after the application of dexamethasone (Dex-; activation of the AP1-GR fusion protein) or a mock solution (Mock-; control). In each of the biological replicates of the time course experiments, all the samples derived from dexamethasone (Dex)-treated plants were labeled with one dye (i.e., Cy3), and all the samples derived from the corresponding Mock-treated plants were labeled with the alternative dye (i.e., Cy5). The dyes used for labeling RNA from a given treatment type (Dex and Mock) were switched for two of the replicate experiments, to reduce dye-related artifacts. Dex- and Mock-derived samples for each timepoint and biological replicate were co-hybridized. This experimental setup resulted in a total of 5 hybridizations per set (0h, 2h, 4, 8h, and 12h; Dex vs. Mock at each timepoint), and two biological replicate sets labeled with each dye polarity (Mock-Cy3/Dex-Cy5, and vice versa). The combined ratio data results are available as a supplementary file on the Series record.
Project description:Arabidopsis thaliana plant expressing 35S:WIND1 shows callus-like morphology without hormone treatment. Transcriptomes of the callus-like cell expressing 35S:WIND1, callus of T87 cultured cell, 2,4-D-induced callus and control seedling plant were compared by Agilent microarray. Comparison of four kinds of Arabidopsis thaliana plants. Biological replicates: three for each.