Combined SHOOT MERISTEMLESS and WUSCHEL trigger ectopic organogenesis inArabidopsis

Development ◽  
2002 ◽  
Vol 129 (13) ◽  
pp. 3207-3217 ◽  
Author(s):  
Jean-Luc Gallois ◽  
Claire Woodward ◽  
G. Venugopala Reddy ◽  
Robert Sablowski
Keyword(s):  
Stem Cells ◽  
Cell Division ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Aerial Parts ◽  
Undifferentiated Cells ◽  
Activate Cell ◽  
Almost All ◽  
Differentiation Pathways ◽  
Shoot Meristemless

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.

TheWUSCHELandSHOOTMERISTEMLESSgenes fulfil complementary roles inArabidopsisshoot meristem regulation

Development ◽  
2002 ◽  
Vol 129 (13) ◽  
pp. 3195-3206 ◽  
Author(s):  
Michael Lenhard ◽  
Gerd Jürgens ◽  
Thomas Laux
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Division ◽  
Pluripotent Stem Cells ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Target Genes ◽  
Cell Specification ◽  
Downstream Target ◽  
Daughter Cells

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.

scholarly journals In Vivo Analysis of Cell Division, Cell Growth, and Differentiation at the Shoot Apical Meristem in Arabidopsis

2003 ◽  
Vol 16 (1) ◽  
pp. 74-87 ◽  
Author(s):  
Olivier Grandjean ◽  
Teva Vernoux ◽  
Patrick Laufs ◽  
Katia Belcram ◽  
Yuki Mizukami ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Growth ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Cell Growth And Differentiation ◽  
In Vivo Analysis ◽  
Division Cell

scholarly journals The CLAVATA and SHOOT MERISTEMLESS loci competitively regulate meristem activity in Arabidopsis

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1567-1575 ◽  
Author(s):  
S.E. Clark ◽  
S.E. Jacobsen ◽  
J.Z. Levin ◽  
E.M. Meyerowitz
Keyword(s):  
Cell Division ◽  
Cell Differentiation ◽  
Embryonic Development ◽  
Genetic Interactions ◽  
Floral Meristem ◽  
Shoot Meristem ◽  
Meristem Development ◽  
Undifferentiated Cells ◽  
Floral Meristems ◽  
Shoot Meristemless

The CLAVATA (CLV1 and CLV3) and SHOOT MERISTEMLESS (STM) genes specifically regulate shoot meristem development in Arabidopsis. CLV and STH appear to have opposite functions: c1v1 and Clv3 mutants accumulate excess undifferentiated cells in the shoot and floral meristem, while stm mutants fail to form the undifferentiated cells of the shoot meristem during embryonic development. We have identified a weak allele of stm (stm-2) that reveals STM is not only required for the establish- ment of the shoot meristem, but is also required for the continued maintenance of undifferentiated cells in the shoot meristem and for proper proliferation of cells in the floral meristem. We have found evidence of genetic interactions between the CLV and STM loci. clv1 and c1v3 mutations partially suppressed the stm-1 and stm-2 phenotypes, and were capable of suppression in a dominant fashion. clv stm double mutants and plants homozygous for stm but heterozygous for clv, while still lacking an embryonic shoot meristem, exhibited greatly enhanced postembryonic shoot and floral meristem development. Although stm phenotypes are recessive, stm mutations dominantly suppressed clv homozygous and heterozygous phenotypes. These results indicate that the stm phenotype is sensitive to the levels of CLV activity, while the clv phenotype is sensitive to the level of STM activity. We propose that these genes play related but opposing roles in the regulation of cell division and/or cell differentiation in shoot and floral meristems.

scholarly journals Integrated Framework of the Immune-Defense Transcriptional Signatures in the Arabidopsis Shoot Apical Meristem

2020 ◽  
Vol 21 (16) ◽  
pp. 5745
Author(s):  
Muhammad Naseem ◽  
Özge Osmanoğlu ◽  
Martin Kaltdorf ◽  
Afnan Ali M. A. Alblooshi ◽  
Jibran Iqbal ◽  
...  
Keyword(s):  
Stem Cells ◽  
Immune Responses ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Large Scale ◽  
Gene Expression Omnibus ◽  
Immune Defense ◽  
Immune Functions ◽  
Pathogen Infection ◽  
Immune Genes

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.

Flower meristem maintenance by TILLERS ABSENT 1 is essential for ovule development in rice

Development ◽  
2021 ◽  
Vol 148 (24) ◽  
Author(s):  
Wakana Tanaka ◽  
Suzuha Ohmori ◽  
Naoto Kawakami ◽  
Hiro-Yuki Hirano
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Flower Development ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Stem Cell Marker ◽  
Ovule Development ◽  
Flower Meristem ◽  
Ovule Formation ◽  
Meristem Maintenance

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.

scholarly journals The shoot apical meristem: the dynamics of a stable structure

2002 ◽  
Vol 357 (1422) ◽  
pp. 737-747 ◽  
Author(s):  
Jan Traas ◽  
Teva Vernoux
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Apparent Contradiction ◽  
Cell Behaviour ◽  
Aerial Parts ◽  
Meristem Identity ◽  
Set Up ◽  
The Stability ◽  
Kinase Pathway ◽  
Stable Network

The shoot apical meristem (SAM) is a group of proliferating, embryonic–type cells that generates the aerial parts of the plant. SAMs are highly organized and stable structures that can function for years or even centuries. This is in apparent contradiction to the behaviour of their constituent cells, which continuously proliferate and differentiate. To reconcile the dynamic nature of the cells with the stability of the overall system the existence of elaborate signalling networks has been proposed. This is supported by recent work suggesting that the exchange of signals between cells, rather than a rigidly predetermined genetic program, is required for the establishment and functioning of an organized meristem. Together these interactions form a stable network, set up during embryogenesis, that assures the coordination of cell behaviour throughout development. Besides meristem–specific signalling cascades such as the CLAVATA receptor kinase pathway, which controls meristem size, these interactions involve plant hormones. In particular, cytokinins and auxins are implicated in the maintenance of meristem identity and phyllotaxis, respectively.

Sign in / Sign up

Export Citation Format

Share Document