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 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 A modified method for enzymatic isolation of and subsequent wax extraction from Arabidopsis thaliana leaf cuticle

Plant Methods ◽  
2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Martina Vráblová ◽  
Daniel Vrábl ◽  
Barbora Sokolová ◽  
Dominika Marková ◽  
Marie Hronková
Keyword(s):  
Arabidopsis Thaliana ◽  
Molecular Genetic ◽  
Enzymatic Method ◽  
Wild Type ◽  
Genetic Studies ◽  
Modified Method ◽  
Enzymatic Isolation ◽  
Cuticular Permeability ◽  
Terrestrial Life ◽  
Intact Leaves

Abstract Background The plant cuticle represents one of the major adaptations of vascular plants to terrestrial life. Cuticular permeability and chemical composition differ among species. Arabidopsis thaliana is a widely used model for biochemical and molecular genetic studies in plants. However, attempts to isolate the intact cuticle from fresh leaves of Arabidopsis have failed so far. The goal of this study was to optimise an enzymatic method for cuticle isolation of species with a thin cuticle and to test it on several A. thaliana wild types and mutants. Results We developed a method for isolation of thin cuticles that allows reducing the isolation time, the separation of abaxial and adaxial cuticles, and avoids formation of wrinkles. Optical microscopy was used for studying cuticle intactness and scanning electron microscopy for visualisation of external and internal cuticle structures after isolation. Wax extracts were analysed by GC–MS. Isolation of intact cuticle was successful for all tested plants. The wax compositions (very-long-chained fatty acids, alcohols and alkanes) of intact leaves and isolated cuticles of wild type Col-0 were compared. Conclusions We conclude that the optimised enzymatic method is suitable for the isolation of A. thaliana adaxial and abaxial cuticles. The isolated cuticles are suitable for microscopic observation. Analysis of wax composition revealed some discrepancies between isolated cuticles and intact leaves with a higher yield of wax in isolated cuticles.

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.

scholarly journals Comparative Ontogeny of Hermaphrodite and Pistillate Florets in Helianthus annuus L. (Asteraceae)

2012 ◽  
Vol 4 (2) ◽  
pp. 30-40 ◽  
Author(s):  
Aslıhan ÇETİNBAŞ ◽  
Meral ÜNAL
Keyword(s):  
Helianthus Annuus ◽  
Apical Meristem ◽  
Floral Organ ◽  
Floral Meristem ◽  
Inferior Ovary ◽  
Helianthus Annuus L ◽  
Stamen Primordia ◽  
Flower Organs ◽  
Short Time ◽  
Further Development

The inflorescence of Helianthus annuus L. has two types of flowers (or florets) on a single capitulum; central hermaphrodite disc florets and peripheral pistillate ray florets. In both florets, reproductive development starts with the conversion of apical meristem into floral meristem that will produce floral organ primordia. The only difference between hermaphrodite and pistillate florets in apical meristem stage is that apical meristem of the pistillate florets is not as apparent and curvaceous as apical meristem of the hermaphrodite florets. The differentiation of apical meristem into floral meristem is in the same progress in both florets. In hermaphrodite florets, flower organs; petals, stamens and carpels develop from floral meristem. Differentiation of five petal primordia takes place in the same way in both florets. Firstly filament and then anther differentiates in a stamen. Two carpel primordia appear below the stamen primordia in hermaphrodite florets. In following stages, carpel primordia are lengthened and formed inferior ovary, style, stigma respectively. In pistillate florets, flower organs; petals and carpels develop from floral meristem. They pass directly from the periant initiation to the start of carpel formation. Stamen primordia don’t appear and the further development of carpel primordia stops in a short time, as a result, stigma and style do not exist in pistillate florets. However, an inferior ovary with no ovule forms. In the capitulum of hermaphrodite florets, the development takes place in a centripetal manner; it starts firstly on the outermost whorl, and it proceeds towards inner whorl. However, this is not the case in pistillate florets.

scholarly journals Expression of KNUCKLES in the Stem Cell Domain Is Required for Its Function in the Control of Floral Meristem Activity in Arabidopsis

2021 ◽  
Vol 12 ◽  
Author(s):  
Kamila Kwaśniewska ◽  
Caoilfhionn Breathnach ◽  
Christina Fitzsimons ◽  
Kevin Goslin ◽  
Bennett Thomson ◽  
...  
Keyword(s):  
Stem Cell ◽  
Regulatory Gene ◽  
Cell Activity ◽  
Floral Organ ◽  
Floral Meristem ◽  
Perturbation Approach ◽  
Expression Domain ◽  
Organ Identity ◽  
Early Expression ◽  
Floral Meristems

In the model plant Arabidopsis thaliana, the zinc-finger transcription factor KNUCKLES (KNU) plays an important role in the termination of floral meristem activity, a process that is crucial for preventing the overgrowth of flowers. The KNU gene is activated in floral meristems by the floral organ identity factor AGAMOUS (AG), and it has been shown that both AG and KNU act in floral meristem control by directly repressing the stem cell regulator WUSCHEL (WUS), which leads to a loss of stem cell activity. When we re-examined the expression pattern of KNU in floral meristems, we found that KNU is expressed throughout the center of floral meristems, which includes, but is considerably broader than the WUS expression domain. We therefore hypothesized that KNU may have additional functions in the control of floral meristem activity. To test this, we employed a gene perturbation approach and knocked down KNU activity at different times and in different domains of the floral meristem. In these experiments we found that early expression in the stem cell domain, which is characterized by the expression of the key meristem regulatory gene CLAVATA3 (CLV3), is crucial for the establishment of KNU expression. The results of additional genetic and molecular analyses suggest that KNU represses floral meristem activity to a large extent by acting on CLV3. Thus, KNU might need to suppress the expression of several meristem regulators to terminate floral meristem activity efficiently.

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.

ETTIN patterns the Arabidopsis floral meristem and reproductive organs

Development ◽  
1997 ◽  
Vol 124 (22) ◽  
pp. 4481-4491 ◽  
Author(s):  
A. Sessions ◽  
J.L. Nemhauser ◽  
A. McColl ◽  
J.L. Roe ◽  
K.A. Feldmann ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Double Mutant ◽  
Regional Identity ◽  
Floral Organ ◽  
Reproductive Organs ◽  
Floral Meristem ◽  
Regional Differentiation ◽  
Organ Identity ◽  
Stage 1 ◽  
Floral Meristems

ettin (ett) mutations have pleiotropic effects on Arabidopsis flower development, causing increases in perianth organ number, decreases in stamen number and anther formation, and apical-basal patterning defects in the gynoecium. The ETTIN gene was cloned and encodes a protein with homology to DNA binding proteins which bind to auxin response elements. ETT transcript is expressed throughout stage 1 floral meristems and subsequently resolves to a complex pattern within petal, stamen and carpel primordia. The data suggest that ETT functions to impart regional identity in floral meristems that affects perianth organ number spacing, stamen formation, and regional differentiation in stamens and the gynoecium. During stage 5, ETT expression appears in a ring at the top of the floral meristem before morphological appearance of the gynoecium, consistent with the proposal that ETT is involved in prepatterning apical and basal boundaries in the gynoecium primordium. Double mutant analyses and expression studies show that although ETT transcriptional activation occurs independently of the meristem and organ identity genes LEAFY, APETELA1, APETELA2 and AGAMOUS, the functioning of these genes is necessary for ETT activity. Double mutant analyses also demonstrate that ETT functions independently of the ‘b’ class genes APETELA3 and PISTILLATA. Lastly, double mutant analyses suggest that ETT control of floral organ number acts independently of CLAVATA loci and redundantly with PERIANTHIA.

scholarly journals The WIGGUM gene is required for proper regulation of floral meristem size in Arabidopsis

Development ◽  
1998 ◽  
Vol 125 (14) ◽  
pp. 2545-2553 ◽  
Author(s):  
M.P. Running ◽  
J.C. Fletcher ◽  
E.M. Meyerowitz
Keyword(s):  
Cell Division ◽  
Apical Meristem ◽  
Critical Role ◽  
Floral Meristem ◽  
Similar Process ◽  
Genetic Studies ◽  
Meristem Size ◽  
Separate Pathway ◽  
Mutant Phenotypes ◽  
Floral Meristems

The study of cell division control within developing tissues is central to understanding the processes of pattern formation. The floral meristem of angiosperms gives rise to floral organs in a particular number and pattern. Despite its critical role, little is known about how cell division is controlled in the floral meristem, and few genes involved have been identified. We describe the phenotypic effects of mutations in WIGGUM, a gene required for control of cell proliferation in the floral and apical meristem of Arabidopsis thaliana. wiggum flowers contain more organs, especially sepals and petals, than found in wild-type flowers. This organ number phenotype correlates with specific size changes in the early floral meristem, preceding organ initiation. Genetic studies suggest that WIGGUM acts on a similar process but in a separate pathway than the CLAVATA1 and CLAVATA3 genes in meristem size regulation, and reveal interactions with other genes affecting meristem structure and identity. Analysis of double mutant phenotypes also reveals a role for WIGGUM in apical meristem function. We propose that WIGGUM plays a role in restricting cell division relative to cellular differentiation in specific regions of the apical and floral meristems.

scholarly journals γ-tubulin gene intron length polymorphism of Arabidopsis thaliana

2020 ◽  
Vol 26 ◽  
pp. 120-124
Author(s):  
A. M. Rabokon ◽  
Yu. O. Bilonozhko ◽  
A. S. PostovoitovA ◽  
L. O. Kalafat ◽  
Ya. V. Pirko ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Length Polymorphism ◽  
Molecular Genetic ◽  
Intron Length ◽  
Degenerate Primers ◽  
Tubulin Gene ◽  
Specific Primers ◽  
Intron Length Polymorphism ◽  
Genetic Studies ◽  
Dna Profile

Aims. Verification of the possibility of using the γ-tubulin gene intron length polymorphism method in genetic studies of plants on the example of Arabidopsis thaliana. Methods. The γ-tubulin gene intron length polymorphism evaluating method was used. Amplified fragments DNA were fractionated by electrophoresis in non-denaturing polyacrylamide gel. DNA bands were detected using silver nitrate staining. Results. Arabidopsis was first time analyzed using the γ-tubulin gene intron length polymorphism method. During amplification with degenerate primers 2 amplicons (520 bp and 555 bp) were formed in all samples. However, using selected arabidopsis-specific primers for the second intron of the γ-tubulin genes, it was possible to find several samples that differ in their DNA profile. Conclusions. It is established that the proposed method can be used in molecular genetic studies of plants. Moreover, the developed specific primers for γ-tubulin gene introns can probably be used both for the study of Arabidopsis and related species. The use of degenerate primers can be useful in the study of plants for which there is no information about their genome. Keywords: molecular-genetic markers, intron length polymorphism, γ-tubulin, A. thaliana.

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