RNAseq experiment to identify differentially expressed genes by AP2 induction in the Shoot Apical Meristem (SAM) of Arabidopsis
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE151082 | GEO | 2020/10/20
REPOSITORIES: GEO
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Project description:The APETALA2 (AP2) transcription factor regulates flower development, floral transition and shoot apical meristem (SAM) maintenance in Arabidopsis. AP2 is also regulated at the post-transcriptional level by microRNA172 (miR172), but the contribution of this to SAM maintenance is poorly understood. We generated transgenic plants carrying a form of AP2 that is resistant to miR172 (rAP2) or carrying a wild-type AP2 susceptible to miR172. Phenotypic and genetic analyses were performed on these lines and mir172 mutants to study the role of AP2 regulation by miR172 on meristem size and the rate of flower production. We found that rAP2 enlarges the inflorescence meristem by increasing cell size and cell number. Misexpression of rAP2 from heterologous promoters showed that AP2 acts in the central zone (CZ) and organizing center (OC) to increase SAM size. Furthermore, we found that AP2 is negatively regulated by AUXIN RESPONSE FACTOR 3 (ARF3). However, genetic analyses indicated that ARF3 also influences SAM size and flower production rate independently of AP2. The study identifies miR172/AP2 as a regulatory module controlling inflorescence meristem size and suggests that transcriptional regulation of AP2 by ARF3 fine tunes SAM size determination.
2022-06-01 | GSE196925 | GEO
Project description:DNA methylation is an epigenetic modification that specifies the basic state of pluripotent stem cells and regulates the developmental transition from stem cells to various cell types. In flowering plants, the shoot apical meristem (SAM) contains a pluripotent stem cell population which generates the aerial part of plants including the germ cells. Under appropriate conditions, the SAM undergoes a developmental transition from a leaf-forming vegetative SAM to an inflorescence- and flower-forming reproductive SAM. While SAM characteristics are largely altered in this transition, the complete picture of DNA methylation remains elusive. Here, by analyzing whole-genome DNA methylation of isolated rice SAMs in the vegetative and reproductive stages, we found that methylation at CHH sites is kept high, particularly at transposable elements (TEs), in the vegetative SAM relative to the differentiated leaf, and increases in the reproductive SAM via the RNA-dependent DNA methylation pathway. We also found that half of the TEs that were highly methylated in gametes had already undergone CHH hypermethylation in the SAM. Our results indicate that changes in DNA methylation begin in the SAM long before germ cell differentiation to protect the genome from harmful TEs.
2020-08-14 | PXD020608 | Pride
Project description:Loss of function mutations in the narrow sheath (ns) duplicate genes (ns1 and ns2) cause the deletion of a mediolateral domain from maize leaves. The ns genes encode duplicate WUSCHEL1-like homeobox (WOX) putative transcription factors that function redundantly and non-cell autonomously to direct recruitment of leaf founder cell-initials in a lateral domain of the shoot apex. In order to investigate the genetic mechanisms of NS1 gene function, SAM-specific transcriptional profiling of narrow sheath mutant1-R comparing to that of nonmutant using laser microdissection microarray. Whole SAMs were laser-microdissected from ns1-R mutant and non-mutant seedlings grown under the same controlled conditions. Microarray profiles were generated for 37,662 maize cDNAs contained on gene chips SAM 1.1, SAM 2.0 and SAM 3.0 (For details, see the the Iowa State University Center for Plant Genomics website). Keywords: Genetic modification
2007-03-14 | GSE7248 | GEO
Project description:The recessive mutation ragged seedling2-R (rgd2-R) conditions defective lateral development of maize leaves. Although dorsiventral patterning is established in rgd2-R mutant leaves, some swapping of adaxial/abaxial epidermal identity may occur. Molecular analyses indicate that RGD2 is required for the coordination of dorsiventral and lateral patterning during maize leaf development, yet the RGD2 gene product and the mechanisms of RGD2 function are unknown. In order to investigate the genetic mechanisms downstream of RGD2 gene function, SAM-specific transcriptional profiling of rgd2-R is compared to that of nonmutant using laser microdissection microarray. Whole SAMs were laser-microdissected from rgd2-R mutant and non-mutant seedlings grown under the same controlled conditions. Microarray profiles were generated for 28,671 maize cDNAs contained on gene chips SAM 1.1and SAM 3.0 (http://www.plantgenomics.iastate.edu/maizechip/). Two-condition experiment, rgd2 SAM vs non-mutant SAM cells. 6 Biological replicates with dye swap. One replicate per array.
2008-05-02 | E-GEOD-11325 | biostudies-arrayexpress
Project description:The recessive mutation ragged seedling2-R (rgd2-R) conditions defective lateral development of maize leaves. Although dorsiventral patterning is established in rgd2-R mutant leaves, some swapping of adaxial/abaxial epidermal identity may occur. Molecular analyses indicate that RGD2 is required for the coordination of dorsiventral and lateral patterning during maize leaf development, yet the RGD2 gene product and the mechanisms of RGD2 function are unknown. In order to investigate the genetic mechanisms downstream of RGD2 gene function, SAM-specific transcriptional profiling of rgd2-R is compared to that of nonmutant using laser microdissection microarray. Whole SAMs were laser-microdissected from rgd2-R mutant and non-mutant seedlings grown under the same controlled conditions. Microarray profiles were generated for 28,671 maize cDNAs contained on gene chips SAM 1.1and SAM 3.0 (http://www.plantgenomics.iastate.edu/maizechip/). Keywords: Genetic modification
2008-05-03 | GSE11325 | GEO
Project description:RNAseq experiment to identify differentially expressed genes by AP2 induction in the Shoot Apical Meristem (SAM) of Arabidopsis
| PRJNA634558 | ENA
Project description:Knowledge about an organism’s cell and tissue-specific transcriptional repertoire is essential for understanding the gene regulatory circuits that control key developmental events. The shoot apical meristem (SAM) is responsible for development of all the above ground parts of plants. Our understanding of SAM at the molecular level is far from complete. The present work investigates the global gene expression repertoire of SAMs in the garden pea (Pisum sativum). To this end, 10,346 EST sequences representing 7611 unique genes were generated from pea SAM cDNA libraries. These sequences, together with previously reported ESTs, were used to construct a 12K oligonucleotide array used to identify genes exhibiting differential SAM expression, as compared to the axillary meristem, root apical meristem, and non-meristematic tissues. We identified a number of genes that are predominantly expressed in specific cell layers or domains of the SAM, and thus are likely components of the gene networks involved in stem cell maintenance and initiation of lateral organ primordial cells. In situ hybridization confirmed the spatial localisation of some of these key genes within the SAM. Our data also indicate the diversification of some gene expression patterns and functions in legume crop plants.
2009-10-26 | GSE13451 | GEO
Project description:In sexually propagating organisms, genetic and epigenetic mutations are evolutionarily relevant only if they occur in the germline and provide inherited information to the next generation. In contrast to most animals, plants are thought to lack an early segregating germline, implying that somatic cells can contribute genetic information to the progeny if they differentiate into meiocytes. Here we demonstrate that two ARGONAUTE proteins, AGO5 and AGO9, are expressed in the reproductive lineage throughout development and mark an early-segregating germline. Furthermore, both AGOs are loaded with dynamic populations of small RNAs derived from highly methylated, pericentromeric, long transposons. Sequencing single nuclei revealed that many of these transposons are highly expressed within a central stem cell domain. This indicates a host-parasite tug of war and specific silencing pathways in plant shoot apical meristems (SAMs). Our results open the path to investigate transposon biology and epigenome dynamics at cellular resolution in the SAM stem cell niche.
2023-10-31 | GSE239462 | GEO
Project description:Enlargement and doming of the shoot apical meristem (SAM) is a hallmark of the transition from vegetative growth to flowering. While this change is widespread, its role in the flowering process is unknown. The late termination (ltm) tomato mutant shows severely delayed flowering and precocious doming of the vegetative SAM. LTM encodes a kelch domain-containing protein, with no link to known meristem maintenance or flowering time pathways. LTM interacts with the TOPLESS (TPL) corepressor and with several transcription factors, providing specificity for its repressive functions. A sub-group of flowering-associated genes are precociously upregulated in vegetative stages of ltm SAMs, among them, the antiflorigen gene SELF PRUNING (SP). A mutation in SP restored the structure of vegetative SAMs in ltm sp double mutants and late flowering was partially suppressed, suggesting LTM functions to suppress SP in the vegetative SAM. In agreement, SP-overexpressing wild type plants exhibited precocious doming of vegetative SAMs combined with late flowering, as found in ltm plants. Strong flowering signals can result in termination of the SAM, usually by its differentiation into a flower. We propose that activation of a floral antagonist that promotes SAM growth in concert with floral transition protects it from such terminating effects.
2017-04-08 | GSE95114 | GEO
Project description:Enlargement and doming of the shoot apical meristem (SAM) is a hallmark of the transition from vegetative growth to flowering. While this change is widespread, its role in the flowering process is unknown. The late termination (ltm) tomato mutant shows severely delayed flowering and precocious doming of the vegetative SAM. LTM encodes a kelch domain-containing protein, with no link to known meristem maintenance or flowering time pathways. LTM interacts with the TOPLESS (TPL) corepressor and with several transcription factors, providing specificity for its repressive functions. A sub-group of flowering-associated genes are precociously upregulated in vegetative stages of ltm SAMs, among them, the antiflorigen gene SELF PRUNING (SP). A mutation in SP restored the structure of vegetative SAMs in ltm sp double mutants and late flowering was partially suppressed, suggesting LTM functions to suppress SP in the vegetative SAM. In agreement, SP-overexpressing wild type plants exhibited precocious doming of vegetative SAMs combined with late flowering, as found in ltm plants. Strong flowering signals can result in termination of the SAM, usually by its differentiation into a flower. We propose that activation of a floral antagonist that promotes SAM growth in concert with floral transition protects it from such terminating effects.
2017-04-08 | GSE95110 | GEO