scholarly journals Plasmodesmata-Mediated Cell-to-Cell Communication in the Shoot Apical Meristem: How Stem Cells Talk

Plants ◽  
2017 ◽  
Vol 6 (4) ◽  
pp. 12 ◽  
Author(s):  
Munenori Kitagawa ◽  
David Jackson
Development ◽  
2002 ◽  
Vol 129 (13) ◽  
pp. 3207-3217 ◽  
Author(s):  
Jean-Luc Gallois ◽  
Claire Woodward ◽  
G. Venugopala Reddy ◽  
Robert Sablowski

Almost all aerial parts of plants are continuously generated at the shoot apical meristem (SAM). To maintain a steady pool of undifferentiated cells in the SAM while continuously generating new organs, it is necessary to balance the rate of cell division with the rate of entrance into differentiation pathways. In the Arabidopsis meristem, SHOOT MERISTEMLESS (STM) and WUSCHEL (WUS) are necessary to keep cells undifferentiated and dividing. Here, we tested whether ectopic STM and WUS functions are sufficient to revert differentiation and activate cell division in differentiating tissues. Ectopic STM and WUS functions interacted non-additively and activated a subset of meristem functions, including cell division, CLAVATA1 expression and organogenesis, but not correct phyllotaxy or meristem self-maintenance. Our results suggest that WUS produces a non-cell autonomous signal that activates cell division in combination with STM and that combined WUS/STM functions can initiate the progression from stem cells to organ initiation.


2020 ◽  
Vol 21 (16) ◽  
pp. 5745
Author(s):  
Muhammad Naseem ◽  
Özge Osmanoğlu ◽  
Martin Kaltdorf ◽  
Afnan Ali M. A. Alblooshi ◽  
Jibran Iqbal ◽  
...  

The growing tips of plants grow sterile; therefore, disease-free plants can be generated from them. How plants safeguard growing apices from pathogen infection is still a mystery. The shoot apical meristem (SAM) is one of the three stem cells niches that give rise to the above ground plant organs. This is very well explored; however, how signaling networks orchestrate immune responses against pathogen infections in the SAM remains unclear. To reconstruct a transcriptional framework of the differentially expressed genes (DEGs) pertaining to various SAM cellular populations, we acquired large-scale transcriptome datasets from the public repository Gene Expression Omnibus (GEO). We identify here distinct sets of genes for various SAM cellular populations that are enriched in immune functions, such as immune defense, pathogen infection, biotic stress, and response to salicylic acid and jasmonic acid and their biosynthetic pathways in the SAM. We further linked those immune genes to their respective proteins and identify interactions among them by mapping a transcriptome-guided SAM-interactome. Furthermore, we compared stem-cells regulated transcriptome with innate immune responses in plants showing transcriptional separation among their DEGs in Arabidopsis. Besides unleashing a repertoire of immune-related genes in the SAM, our analysis provides a SAM-interactome that will help the community in designing functional experiments to study the specific defense dynamics of the SAM-cellular populations. Moreover, our study promotes the essence of large-scale omics data re-analysis, allowing a fresh look at the SAM-cellular transcriptome repurposing data-sets for new questions.


Development ◽  
2021 ◽  
Vol 148 (24) ◽  
Author(s):  
Wakana Tanaka ◽  
Suzuha Ohmori ◽  
Naoto Kawakami ◽  
Hiro-Yuki Hirano

ABSTRACT Plant development depends on the activity of pluripotent stem cells in meristems, such as the shoot apical meristem and the flower meristem. In Arabidopsis thaliana, WUSCHEL (WUS) is essential for stem cell homeostasis in meristems and integument differentiation in ovule development. In rice (Oryza sativa), the WUS ortholog TILLERS ABSENT 1 (TAB1) promotes stem cell fate in axillary meristem development, but its function is unrelated to shoot apical meristem maintenance in vegetative development. In this study, we examined the role of TAB1 in flower development. The ovule, which originates directly from the flower meristem, failed to differentiate in tab1 mutants, suggesting that TAB1 is required for ovule formation. Expression of a stem cell marker was completely absent in the flower meristem at the ovule initiation stage, indicating that TAB1 is essential for stem cell maintenance in the ‘final’ flower meristem. The ovule defect in tab1 was partially rescued by floral organ number 2 mutation, which causes overproliferation of stem cells. Collectively, it is likely that TAB1 promotes ovule formation by maintaining stem cells at a later stage of flower development.


Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 136
Author(s):  
Tianqi Jia ◽  
Fan Li ◽  
Shuang Liu ◽  
Jin Dou ◽  
Tao Huang

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.


Development ◽  
2002 ◽  
Vol 129 (13) ◽  
pp. 3195-3206 ◽  
Author(s):  
Michael Lenhard ◽  
Gerd Jürgens ◽  
Thomas Laux

Continuous organ formation from the shoot apical meristem requires the integration of two functions: a set of undifferentiated, pluripotent stem cells is maintained at the very tip of the meristem, while their daughter cells in the periphery initiate organ primordia. The homeobox genes WUSCHEL (WUS) and SHOOTMERISTEMLESS (STM) encode two major regulators of meristem formation and maintenance in Arabidopsis, yet their interaction in meristem regulation is presently unclear. Here, we have addressed this question using loss- and gain-of-function approaches. We show that stem cell specification by WUS does not require STM activity. Conversely, STM suppresses differentiation independently of WUS and is required and sufficient to promote cell division. Consistent with their independent and distinct phenotypic effects, ectopic WUS and STM activities induce the expression of different downstream target genes. Finally, the pathways regulated by WUS and STM appear to converge in the suppression of differentiation, since coexpression of both genes produced a synergistic effect, and increased WUS activity could partly compensate for loss of STM function. These results suggest that WUS and STM share labour in the shoot apical meristem: WUS specifies a subset of cells in the centre as stem cells, while STM is required to suppress differentiation throughout the meristem dome, thus allowing stem cell daughters to be amplified before they are incorporated into organs.


Author(s):  
Hariharan Jayaraman ◽  
Nalinkanth V. Ghone ◽  
Ranjith Kumaran R ◽  
Himanshu Dashora

: Mesenchymal stem cells because of its high proliferation, differentiation, regenerative capacity, and ease of availability have been a popular choice in cytotherapy. Mesenchymal Stem Cells (MSCs) have a natural tendency to home in a tumor microenvironment and acts against it, owing to the similarity of the latter to an injured tissue environment. Several studies have confirmed the recruitment of MSCs by tumor through various cytokine signaling that brings about phenotypic changes to cancer cells, thereby promoting migration, invasion, and adhesion of cancer cells. The contrasting results on MSCs as a tool for cancer cytotherapy may be due to the complex cell to cell interaction in the tumor microenvironment, which involves various cell types such as cancer cells, immune cells, endothelial cells, and cancer stem cells. Cell to cell communication can be simple or complex and it is transmitted through various cytokines among multiple cell phenotypes, mechano-elasticity of the extra-cellular matrix surrounding the cancer cells, and hypoxic environments. In this article, the role of the extra-cellular matrix proteins and soluble mediators that acts as communicators between mesenchymal stem cells and cancer cells has been reviewed specifically for breast cancer, as it is the leading member of cancer malignancies. The comprehensive information may be beneficial in finding a new combinatorial cytotherapeutic strategy using MSCs by exploiting the cross-talk between mesenchymal stem cells and cancer cells for treating breast cancer.


Author(s):  
Nicola Alessio ◽  
Anna Lisa Brigida ◽  
Gianfranco Peluso ◽  
Nicola Antonucci ◽  
Umberto Galderisi ◽  
...  

Neurodevelopmental lifelong pathologies defined by problems with social interaction, communication capacity and presence of repetitive/stereotyped clusters of behavior and interests are grouped under the definition of autism spectrum disorder (ASD). ASD prevalence is still increasing, indicating the need to identify specific biomarkers and novel pharmacotherapies. Neuroinflammation and neuro-immune cross-talk dysregulation are specific hallmarks of ASD, offering the possibility of treating these disorders by stem cell therapy. Indeed, cellular strategies have been postulated, proposed and applied to ASD. However, less is known about the molecular action mechanisms of stem cells. As a possibility, the positive and restorative effects mediated by stem cells could be due to their paracrine activity, by which stem cells produce and release several ameliorative and anti-inflammatory molecules. Among the secreted complex tools, exosomes are sub-organelles, enriched by RNA and proteins, that provide cell-to-cell communication. Exosomes could be the mediators of many stem cell-associated therapeutic activities. This review article describes the potential role of exosomes in alleviating ASD symptoms.


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