Similar Datasets
Project description:Arabidopsis microRNA165a (miR165a) targets Class III Homeodomain Leucine-Zipper (HD-ZIPIII) transcription factors to regulate various aspects of plant development and stress response. Over-expression of miR165a mimics the loss-of-function phenotype of HD-ZIPIII genes and leading to ectopic organ formation, shoot apical meristem (SAM) termination, loss of leaf polarity, and defective vasculature development. However, the molecular mechanisms underlying these phenotypes remain unresolved. Here, we over-expressed miR165a in a dexamethasone inducible manner and identified differentially expressed genes in the SAM through RNA-Seq. Simultaneously, using multi-channel FACS combined with RNA-Seq approach, we characterized global transcriptome patterns in miR165a expressing cell-types compared to HD-ZIPIII expressing cell-types and other cell-types in SAM. By integrating our results we identified sets of genes which are up-regulated by miR165a as well have enriched expression in miR165a cell-types, and vice-versa. Known plant development related genes such as HD-ZIPIII and their targets LITTLE ZIPPERs, Like AUXIN RESISTANT 2, BEL1-like homeodomain 6, ROTUNDIFOLIA like 16 were found to be down-regulated. Among the up-regulated genes, GIBBERELLIN 2-OXIDASEs, various elemental transporters (YSL3, ZIFL1, SULTR), and other transporter genes were prominent. Thus, the genes identified in this study help to unravel the molecular mechanism of miR165a and HD-ZIPIII regulated plant development and stress response.
| S-EPMC10721644 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2023-09-30 | GSE192611 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2021-03-26 | GSE144049 | GEO
Project description:The shoot apical meristem (SAM) ensures continuous plant growth and organogenesis. In LD 30 °C, plants lacking AtFTSH4, an ATP-dependent mitochondrial protease that counteracts accumulation of internal oxidative stress, exhibit a puzzling phenotype of premature SAM termination. We aimed to elucidate the underlying cellular and molecular processes that link AtFTSH4 with SAM arrest. We studied AtFTSH4 expression, internal oxidative stress accumulation, and SAM morphology. Directly in the SAM we analysed H2O2 accumulation, mitochondria behaviour, and identity of stem cells using WUS/CLV3 expression. AtFTSH4 was expressed in proliferating tissues, particularly during the reproductive phase. In the mutant, SAM, in which internal oxidative stress accumulates predominantly at 30 °C, lost its meristematic fate. This process was progressive and stage-specific. Premature meristem termination was associated with an expansion in SAM area, where mitochondria lost their functionality. All these effects destabilised the identity of the stem cells. SAM termination in ftsh4 mutants is caused both by internal oxidative stress accumulation with time/age and by the tissue-specific role of AtFTSH4 around the flowering transition. Maintaining mitochondria functionality within the SAM, dependent on AtFTSH4, is vital to preserving stem cell activity throughout development.
| S-EPMC4913265 | biostudies-literature
Project description:Plants produce new organs post-embryonically throughout their entire life cycle. This is due to stem cells present in the shoot and root apical meristems, the SAM and RAM, respectively. In the SAM, stem cells are located in the central zone where they divide slowly. Stem cell daughters are displaced laterally and enter the peripheral zone, where their mitotic activity increases and lateral organ primordia are formed. How the spatial arrangement of these different domains is initiated and controlled during SAM growth and development, and how sites of lateral organ primordia are determined in the peripheral zone is not yet completely understood. We found that the SHORTROOT (SHR) transcription factor together with its target transcription factors SCARECROW (SCR), SCARECROW-LIKE23 (SCL23) and JACKDAW (JKD), promotes formation of lateral organs and controls shoot meristem size. SHR, SCR, SCL23, and JKD are expressed in distinct, but partially overlapping patterns in the SAM. They can physically interact and activate expression of key cell cycle regulators such as CYCLIND6;1 (CYCD6;1) to promote the formation of new cell layers. In the peripheral zone, auxin accumulates at sites of lateral organ primordia initiation and activates SHR expression via the auxin response factor MONOPTEROS (MP) and auxin response elements in the SHR promoter. In the central zone, the SHR-target SCL23 physically interacts with the key stem cell regulator WUSCHEL (WUS) to promote stem cell fate. Both SCL23 and WUS expression are subject to negative feedback regulation from stem cells through the CLAVATA signaling pathway. Together, our findings illustrate how SHR-dependent transcription factor complexes act in different domains of the shoot meristem to mediate cell division and auxin dependent organ initiation in the peripheral zone, and coordinate this activity with stem cell maintenance in the central zone of the SAM.
| S-EPMC10642969 | biostudies-literature
Project description:The stereotypic pattern of cell shapes in the Arabidopsis shoot apical meristem (SAM) suggests that strict rules govern the placement of new walls during cell division. When a cell in the SAM divides, a new wall is built that connects existing walls and divides the cytoplasm of the daughter cells. Because features that are determined by the placement of new walls such as cell size, shape, and number of neighbors are highly regular, rules must exist for maintaining such order. Here we present a quantitative model of these rules that incorporates different observed features of cell division. Each feature is incorporated into a "potential function" that contributes a single term to a total analog of potential energy. New cell walls are predicted to occur at locations where the potential function is minimized. Quantitative terms that represent the well-known historical rules of plant cell division, such as those given by Hofmeister, Errera, and Sachs are developed and evaluated against observed cell divisions in the epidermal layer (L1) of Arabidopsis thaliana SAM. The method is general enough to allow additional terms for nongeometric properties such as internal concentration gradients and mechanical tensile forces.
| S-EPMC4403164 | biostudies-literature
Project description:WUSCHEL (WUS) protein regulates stem cell function in shoot apical meristem of Arabidopsis. The expression of WUS gene is strictly regulated by developmental cues and environmental factors. As DnaJ domain-containing proteins, SDJ1 and SDJ3 have been proven to play an important role in transcriptional activation of promoter methylated genes. Here, we showed that three DnaJ domain-containing proteins including SDJ1 and SDJ3 can bind WUS protein as a complex, which further maintain the expression of WUS gene by binding to WUS promoter. We propose a model how DnaJ domain-containing proteins are involved in the self-regulation of WUS gene in stem cells maintenance of Arabidopsis.
| S-EPMC7827474 | biostudies-literature
Project description:BackgroundIn plants, the shoot apical meristem (SAM) has two main functions, involving the production of all aerial organs on the one hand and self-maintenance on the other, allowing the production of organs during the entire post-embryonic life of the plant. Transcription factors, microRNA, hormones, peptides and forces have been involved in meristem function. Whereas phosphatidylinositol phosphates (PIPs) have been involved in almost all biological functions, including stem cell maintenance and organogenesis in animals, the processes in meristem biology to which PIPs contribute still need to be delineated.ResultsUsing biosensors for PI4P and PI(4,5)P2, the two most abundant PIPs at the plasma membrane, we reveal that meristem functions are associated with a stereotypical PIP tissue-scale pattern, with PI(4,5)P2 always displaying a more clear-cut pattern than PI4P. Using clavata3 and pin-formed1 mutants, we show that stem cell maintenance is associated with reduced levels of PIPs. In contrast, high PIP levels are signatures for organ-meristem boundaries. Interestingly, this pattern echoes that of cortical microtubules and stress anisotropy at the meristem. Using ablations and pharmacological approaches, we further show that PIP levels can be increased when the tensile stress pattern is altered. Conversely, we find that katanin mutant meristems, with increased isotropy of microtubule arrays and slower response to mechanical perturbations, exhibit reduced PIP gradients within the SAM. Comparable PIP pattern defects were observed in phospholipase A3β overexpressor lines, which largely phenocopy katanin mutants at the whole plant level.ConclusionsUsing phospholipid biosensors, we identified a stereotypical PIP accumulation pattern in the SAM that negatively correlates with stem cell maintenance and positively correlates with organ-boundary establishment. While other cues are very likely to contribute to the final PIP pattern, we provide evidence that the patterns of PIP, cortical microtubules and mechanical stress are positively correlated, suggesting that the PIP pattern, and its reproducibility, relies at least in part on the mechanical status of the SAM.
| S-EPMC5803925 | biostudies-literature
Project description:Spatial gene regulatory network of miRNA165a in Shoot apical meristem of Arabidopsis
| PRJNA913098 | ENA
Project description:In plants, the shoot apical meristem (SAM) serves as a reservoir of pluripotent stem cells from which all above ground organs originate. To sustain proper growth, the SAM must maintain homeostasis between the self-renewal of pluripotent stem cells and cell recruitment for lateral organ formation. At the core of the network that regulates this homeostasis in Arabidopsis are the WUSCHEL (WUS) transcription factor specifying stem cell fate and the CLAVATA (CLV) ligand-receptor system limiting WUS expression. In this study, we identified the ERECTA (ER) pathway as a second receptor kinase signaling pathway that regulates WUS expression, and therefore shoot apical and floral meristem size, independently of the CLV pathway. We demonstrate that reduction in class III HD-ZIP and ER function together leads to a significant increase in WUS expression, resulting in extremely enlarged shoot meristems and a switch from spiral to whorled vegetative phyllotaxy. We further show that strong upregulation of WUS in the inflorescence meristem leads to ectopic expression of the AGAMOUS homeotic gene to a level that switches cell fate from floral meristem founder cell to carpel founder cell, suggesting an indirect role for ER in regulating floral meristem identity. This work illustrates the delicate balance between stem cell specification and differentiation in the meristem and shows that a shift in this balance leads to abnormal phyllotaxy and to altered reproductive cell fate.
| S-EPMC3930468 | biostudies-literature