scholarly journals CLAVATA3 is a specific regulator of shoot and floral meristem development affecting the same processes as CLAVATA1

Development ◽  
1995 ◽  
Vol 121 (7) ◽  
pp. 2057-2067 ◽  
Author(s):  
S. E. Clark ◽  
M. P. Running ◽  
E. M. Meyerowitz
Keyword(s):  
Arabidopsis Thaliana ◽  
Flower Development ◽  
Mature Embryo ◽  
Floral Meristem ◽  
Wild Type ◽  
Apical Meristems ◽  
Meristem Development ◽  
Embryo Stage ◽  
Double Heterozygosity ◽  
Floral Meristems

We have previously described the phenotype of Arabidopsis thaliana plants with mutations at the CLAVATA1 (CLV1) locus (Clark, S. E., Running, M. P. and Meyerowitz, E. M. (1993) Development 119, 397–418). Our investigations demonstrated that clv1 plants develop enlarged vegetative and inflorescence apical meristems, and enlarged and indeterminate floral meristems. Here, we present an analysis of mutations at a separate locus, CLAVATA3 (CLV3), that disrupt meristem development in a manner similar to clv1 mutations. clv3 plants develop enlarged apical meristems as early as the mature embryo stage. clv3 floral meristems are also enlarged compared with wild type, and maintain a proliferating meristem throughout flower development. clv3 root meristems are unaffected, indicating that CLV3 is a specific regulator of shoot and floral meristem development. We demonstrate that the strong clv3-2 mutant is largely epistatic to clv1 mutants, and that the semi- dominance of clv1 alleles is enhanced by double heterozygosity with clv3 alleles, suggesting that these genes work in the same pathway to control meristem development. We propose that CLV1 and CLV3 are required to promote the differentiation of cells at the shoot and floral meristem.

scholarly journals CLAVATA1, a regulator of meristem and flower development in Arabidopsis

Development ◽  
1993 ◽  
Vol 119 (2) ◽  
pp. 397-418 ◽  
Author(s):  
S.E. Clark ◽  
M.P. Running ◽  
E.M. Meyerowitz
Keyword(s):  
Flower Development ◽  
Double Mutant ◽  
Apical Meristem ◽  
Expression Patterns ◽  
Floral Meristem ◽  
Homeotic Genes ◽  
Wild Type ◽  
Meristem Identity ◽  
Floral Meristems ◽  
Transition To Flowering

We have investigated the effects on plant development of mutations in the Arabidopsis thaliana CLAVATA1 gene. In clavata1 plants, vegetative, inflorescence and floral meristems are all enlarged relative to wild type. The apical meristem can fasciate in the more severe mutant alleles, and this fasciation can occur prior to the transition to flowering. Flowers of clavata1 plants can have increased numbers of organs in all four whorls, and can also have additional whorls not present in wild-type flowers. Double mutant combinations of clavata1 with agamous, apetala2, apetala3 and pistillata indicate that CLAVATA1 controls the underlying floral meristem structure upon which these homeotic genes act. Double mutant combinations of clavata1 with apetala1 and leafy indicate CLAVATA1 plays a role in establishing and maintaining floral meristem identity, in addition to its role in controlling meristem size. In support of this, RNA expression patterns of AGAMOUS and APETALA1 are altered in clavata1 flowers.

The ULTRAPETALA gene controls shoot and floral meristem size in Arabidopsis

Development ◽  
2001 ◽  
Vol 128 (8) ◽  
pp. 1323-1333 ◽  
Author(s):  
J.C. Fletcher
Keyword(s):  
Signal Transduction Pathway ◽  
Floral Meristem ◽  
Transduction Pathway ◽  
Wild Type ◽  
Inflorescence Meristem ◽  
Genetic Studies ◽  
Meristem Cell ◽  
Meristem Size ◽  
Cell Accumulation ◽  
Floral Meristems

The regulation of proper shoot and floral meristem size during plant development is mediated by a complex interaction of stem cell promoting and restricting factors. The phenotypic effects of mutations in the ULTRAPETALA gene, which is required to control shoot and floral meristem cell accumulation in Arabidopsis thaliana, are described. ultrapetala flowers contain more floral organs and whorls than wild-type plants, phenotypes that correlate with an increase in floral meristem size preceding organ initiation. ultrapetala plants also produce more floral meristems than wild-type plants, correlating with an increase in inflorescence meristem size without visible fasciation. Expression analysis indicates that ULTRAPETALA controls meristem cell accumulation partly by limiting the domain of CLAVATA1 expression. Genetic studies show that ULTRAPETALA acts independently of ERA1, but has overlapping functions with PERIANTHIA and the CLAVATA signal transduction pathway in controlling shoot and floral meristem size and meristem determinacy. Thus ULTRAPETALA defines a novel locus that restricts meristem cell accumulation in Arabidopsis shoot and floral meristems.

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 Quantitative live-imaging of Aquilegia floral meristems reveals distinct patterns of floral organ initiation and cell-level dynamics of floral meristem termination

2021 ◽  
Author(s):  
Ya Min ◽  
Stephanie J. Conway ◽  
Elena M. Kramer
Keyword(s):  
Cell Division ◽  
Floral Organ ◽  
Live Imaging ◽  
Confocal Imaging ◽  
Floral Meristem ◽  
Flowering Plant ◽  
Molecular Networks ◽  
Floral Organs ◽  
Meristem Development ◽  
Floral Meristems

ABSTRACTIn-depth investigation of any developmental process in plants requires knowledge of both the underpinning molecular networks and how they directly determine patterns of cell division and expansion over time. Floral meristems (FM) produce floral organs, after which they undergo floral meristem termination (FMT), and precise control of organ initiation and FMT is crucial to reproductive success of any flowering plant. Using a live confocal imaging, we characterized developmental dynamics during floral organ primordia initiation and FMT in Aquilegia coerulea (Ranunculaceae). Our results have uncovered distinct patterns of primordium initiation between stamens and staminodes compared to carpels, and provided insight into the process of FMT, which is discernable based on cell division dynamics preceding carpel initiation. To our knowledge, this is the first quantitative live imaging of meristem development in a system with numerous whorls of floral organs as well as an apocarpous gynoecium. This study provides crucial information for our understanding of how the spatial-temporal regulation of floral meristem behavior is achieved in both an evolutionary and developmental context.

POLTERGEIST functions to regulate meristem development downstream of the CLAVATA loci

Development ◽  
2000 ◽  
Vol 127 (8) ◽  
pp. 1661-1670 ◽  
Author(s):  
L.P. Yu ◽  
E.J. Simon ◽  
A.E. Trotochaud ◽  
S.E. Clark
Keyword(s):  
Receptor Activation ◽  
Complete Suppression ◽  
Wild Type ◽  
Meristem Development ◽  
Undifferentiated Cells ◽  
Partial Suppression ◽  
Floral Meristems

Mutations at the CLAVATA loci (CLV1, CLV2 and CLV3) result in the accumulation of undifferentiated cells at the shoot and floral meristems. We have isolated three mutant alleles of a novel locus, POLTERGEIST (POL), as suppressors of clv1, clv2 and clv3 phenotypes. All pol mutants were nearly indistinguishable from wild-type plants; however, pol mutations provided recessive, partial suppression of meristem defects in strong clv1 and clv3 mutants, and nearly complete suppression of weak clv1 mutants. pol mutations partially suppressed clv2 floral and pedicel defects in a dominant fashion, and almost completely suppressed clv2 phenotypes in a recessive manner. These observations, along with dominant interactions observed between the pol and wuschel (wus) mutations, indicate that POL functions as a critical regulator of meristem development downstream of the CLV loci and redundantly with WUS. Consistent with this, pol mutations do not suppress clv3 phenotypes by altering CLV1 receptor activation.

The REVOLUTA gene is necessary for apical meristem development and for limiting cell divisions in the leaves and stems of Arabidopsis thaliana

Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 2723-2735 ◽  
Author(s):  
P.B. Talbert ◽  
H.T. Adler ◽  
D.W. Parks ◽  
L. Comai
Keyword(s):  
Arabidopsis Thaliana ◽  
Apical Meristem ◽  
Leaf Growth ◽  
Leaf Axil ◽  
Axillary Shoots ◽  
Apical Meristems ◽  
Cell Divisions ◽  
Meristem Development ◽  
Cell Layers ◽  
Recessive Mutant

The form of seed plants is determined by the growth of a number of meristems including apical meristems, leaf meristems and cambium layers. We investigated five recessive mutant alleles of a gene REVOLUTA that is required to promote the growth of apical meristems and to limit cell division in leaves and stems of Arabidopsis thaliana. REVOLUTA maps to the bottom of the fifth chromosome. Apical meristems of both paraclades (axillary shoots) and flowers of revoluta mutants frequently fail to complete normal development and form incomplete or abortive structures. The primary shoot apical meristem sometimes also arrests development early. Leaves, stems and floral organs, in contrast, grow abnormally large. We show that in the leaf epidermis this extra growth is due to extra cell divisions in the leaf basal meristem. The extent of leaf growth is negatively correlated with the development of a paraclade in the leaf axil. The thickened stems contain extra cell layers, arranged in rings, indicating that they may result from a cambium-like meristem. These results suggest that the REVOLUTA gene has a role in regulating the relative growth of apical and non-apical meristems in Arabidopsis.

scholarly journals Then There Were Plenty-Ring Meristems Giving Rise to Many Stamen Whorls

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1140
Author(s):  
Doudou Kong ◽  
Annette Becker
Keyword(s):  
Arabidopsis Thaliana ◽  
Dynamic Systems ◽  
Molecular Genetic ◽  
Floral Organ ◽  
Fixed Number ◽  
Floral Meristem ◽  
Ecological Value ◽  
Genetic Studies ◽  
Stamen Primordia ◽  
Floral Meristems

Floral meristems are dynamic systems that generate floral organ primordia at their flanks and, in most species, terminate while giving rise to the gynoecium primordia. However, we find species with floral meristems that generate additional ring meristems repeatedly throughout angiosperm history. Ring meristems produce only stamen primordia, resulting in polystemous flowers (having stamen numbers more than double that of petals or sepals), and act independently of the floral meristem activity. Most of our knowledge on floral meristem regulation is derived from molecular genetic studies of Arabidopsis thaliana, a species with a fixed number of floral organs and, as such of only limited value for understanding ring meristem function, regulation, and ecological value. This review provides an overview of the main molecular players regulating floral meristem activity in A. thaliana and summarizes our knowledge of ring primordia morphology and occurrence in dicots. Our work provides a first step toward understanding the significance and molecular genetics of ring meristem regulation and evolution.

The additional stamens of flo10-1 mutants of Arabidopsis thaliana are compromised in production and viability of pollen

1998 ◽  
Vol 76 (10) ◽  
pp. 1733-1742
Author(s):  
Jeffrey D Pylatuik ◽  
Peta C Bonham-Smith ◽  
Arthur R Davis
Keyword(s):  
Arabidopsis Thaliana ◽  
Flower Development ◽  
Male Fertility ◽  
Pollen Viability ◽  
Wild Type ◽  
Viable Pollen ◽  
Stamen Number ◽  
Significant Difference

flo10-1 (superman-2) is a floral mutant in Arabidopsis thaliana that normally produces female sterile flowers. This phenotypic aberration results from a combination of increased stamen number and reduced or abnormal carpels that are nonfunctional. The flowers of flo10-1 contain two lateral and four median stamens, as seen in wild-type plants; however, they also contain several additional stamens. All stamen types have been examined with respect to frequency and location within the flower. The amount of pollen produced from each of the three types of stamens of flo10-1 and the viability of this pollen were also examined and compared with wild-type (cv. Columbia) to determine the consequences of this mutation on male fertility. Both the lateral and median stamens of flo10-1 and wild-type plants produced similar amounts of pollen per stamen and demonstrated no significant difference in viability. Per stamen, the additionals of flo10-1 produced significantly less pollen than those of the laterals and medians. Furthermore, the pollen produced from these additional stamens was significantly less viable. Although less abundant and viable, pollen produced by additional stamens can effectively fertilize ovules, producing normal, healthy plants.Key words: pollen (viability, production), stamen, male fertility, flower development, Arabidopsis thaliana, flo10-1.

scholarly journals Floral Meristem Development in Cranberry Apical Buds during Winter Rest and Its Implication on Yield Prediction

2019 ◽  
Vol 144 (5) ◽  
pp. 314-320
Author(s):  
Jenny L. Bolivar-Medina ◽  
Camilo Villouta ◽  
Beth Ann Workmaster ◽  
Amaya Atucha
Keyword(s):  
Histological Study ◽  
Development Stage ◽  
Fruit Production ◽  
Floral Meristem ◽  
Limited Information ◽  
Apical Buds ◽  
Meristem Development ◽  
Bud Size ◽  
Crop Forecasting ◽  
Floral Meristems

The formation and development of floral meristems is key to fruit production. However, limited information regarding the development of floral buds during the dormant period of cranberry (Vaccinium macrocarpon) constrains the ability to forecast yield early and accurately. The objectives of this study were to characterize the development of floral meristems from fall to spring and to evaluate the number of floral meristems formed across different bud sizes and upright types, as well as their contribution to the fruit production of the next year. Apical buds of different sizes on vegetative and fruiting uprights were tagged and collected periodically from fall to spring for histological study. An extra set of tagged buds was left in the field to evaluate their flower and fruit production. Five stages of floral development were identified based on the concentric differentiation of organ primordia. Large buds from vegetative uprights developed earlier, had a higher number of floral meristems, and became fruiting uprights; they had the highest number of flowers and fruit. Buds from fruiting uprights had the lowest number of floral meristems and delayed development; subsequently, they had the lowest number of fruit per upright. Our results provide evidence of active floral meristem differentiation during fall and winter, as well as differences in the timing and development stage according to bud size. In addition, our study shows that upright types and bud sizes influence the fruit production of the following year; therefore, they should be considered in cranberry crop forecasting models.

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