scholarly journals Molecular and Hormonal Regulation of Leaf Morphogenesis in Arabidopsis

2020 ◽  
Vol 21 (14) ◽  
pp. 5132 ◽  
Author(s):  
Shahid Ali ◽  
Naeem Khan ◽  
Linan Xie
Keyword(s):  
Cell Fate ◽  
Leaf Development ◽  
Hormonal Regulation ◽  
Small Peptides ◽  
Leaf Morphogenesis ◽  
Leaf Initiation ◽  
Over Expression ◽  
Lateral Organs ◽  
Small Pool ◽  
A Site

Shoot apical meristems (SAM) are tissues that function as a site of continuous organogenesis, which indicates that a small pool of pluripotent stem cells replenishes into lateral organs. The coordination of intercellular and intracellular networks is essential for maintaining SAM structure and size and also leads to patterning and formation of lateral organs. Leaves initiate from the flanks of SAM and then develop into a flattened structure with variable sizes and forms. This process is mainly regulated by the transcriptional regulators and mechanical properties that modulate leaf development. Leaf initiation along with proper orientation is necessary for photosynthesis and thus vital for plant survival. Leaf development is controlled by different components such as hormones, transcription factors, miRNAs, small peptides, and epigenetic marks. Moreover, the adaxial/abaxial cell fate, lamina growth, and shape of margins are determined by certain regulatory mechanisms. The over-expression and repression of various factors responsible for leaf initiation, development, and shape have been previously studied in several mutants. However, in this review, we collectively discuss how these factors modulate leaf development in the context of leaf initiation, polarity establishment, leaf flattening and shape.

scholarly journals Drosophila Notch receptor activity suppresses Hairless function during adult external sensory organ development.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1491-1505
Author(s):  
D F Lyman ◽  
B Yedvobnick
Keyword(s):  
Cell Fate ◽  
Daughter Cell ◽  
Notch Receptor ◽  
Sensory Organ ◽  
Cell Fates ◽  
Gain Of Function ◽  
Over Expression ◽  
Cell Fate Decisions ◽  
Synergistic Enhancement ◽  
Conditional Expression

Abstract The neurogenic Notch locus of Drosophila encodes a receptor necessary for cell fate decisions within equivalence groups, such as proneural clusters. Specification of alternate fates within clusters results from inhibitory communication among cells having comparable neural fate potential. Genetically, Hairless (H) acts as an antagonist of most neurogenic genes and may insulate neural precursor cells from inhibition. H function is required for commitment to the bristle sensory organ precursor (SOP) cell fate and for daughter cell fates. Using Notch gain-of-function alleles and conditional expression of an activated Notch transgene, we show that enhanced signaling produces H-like loss-of-function phenotypes by suppressing bristle SOP cell specification or by causing an H-like transformation of sensillum daughter cell fates. Furthermore, adults carrying Notch gain of function and H alleles exhibit synergistic enhancement of mutant phenotypes. Over-expression of an H+ transgene product suppressed virtually all phenotypes generated by Notch gain-of-function genotypes. Phenotypes resulting from over-expression of the H+ transgene were blocked by the Notch gain-of-function products, indicating a balance between Notch and H activity. The results suggest that H insulates SOP cells from inhibition and indicate that H activity is suppressed by Notch signaling.

scholarly journals Genome-wide analysis of changes in miRNA and target gene expression reveals key roles in heterosis for Chinese cabbage biomass

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Peirong Li ◽  
Tongbing Su ◽  
Deshuang Zhang ◽  
Weihong Wang ◽  
Xiaoyun Xin ◽  
...  
Keyword(s):  
Chinese Cabbage ◽  
Leaf Development ◽  
Target Genes ◽  
Expression Patterns ◽  
Seedling Stage ◽  
Differentially Expressed ◽  
Small Rna Sequencing ◽  
Leaf Morphogenesis ◽  
Expression Levels ◽  
Parental Lines

AbstractHeterosis is a complex phenomenon in which hybrids show better phenotypic characteristics than their parents do. Chinese cabbage (Brassica rapa L. spp. pekinensis) is a popular leafy crop species, hybrids of which are widely used in commercial production; however, the molecular basis of heterosis for biomass of Chinese cabbage is poorly understood. We characterized heterosis in a Chinese cabbage F1 hybrid cultivar and its parental lines from the seedling stage to the heading stage; marked heterosis of leaf weight and biomass yield were observed. Small RNA sequencing revealed 63 and 50 differentially expressed microRNAs (DEMs) at the seedling and early-heading stages, respectively. The expression levels of the majority of miRNA clusters in the F1 hybrid were lower than the mid-parent values (MPVs). Using degradome sequencing, we identified 1,819 miRNA target genes. Gene ontology (GO) analyses demonstrated that the target genes of the MPV-DEMs and low parental expression level dominance (ELD) miRNAs were significantly enriched in leaf morphogenesis, leaf development, and leaf shaping. Transcriptome analysis revealed that the expression levels of photosynthesis and chlorophyll synthesis-related MPV-DEGs (differentially expressed genes) were significantly different in the F1 hybrid compared to the parental lines, resulting in increased photosynthesis capacity and chlorophyll content in the former. Furthermore, expression of genes known to regulate leaf development was also observed at the seedling stage. Arabidopsis plants overexpressing BrGRF4.2 and bra-miR396 presented increased and decreased leaf sizes, respectively. These results provide new insight into the regulation of target genes and miRNA expression patterns in leaf size and heterosis for biomass of B. rapa.

scholarly journals Taking a Step Back: Insights into the Mechanisms Regulating Gut Epithelial Dedifferentiation

2021 ◽  
Vol 22 (13) ◽  
pp. 7043
Author(s):  
Shaida Ouladan ◽  
Alex Gregorieff
Keyword(s):  
Cell Fate ◽  
Hormonal Regulation ◽  
Transcriptional Profiling ◽  
Cell Types ◽  
Lineage Tracing ◽  
Intestinal Stem Cells ◽  
Physical Damage ◽  
Epithelial Regeneration ◽  
Gut Epithelium ◽  
Stem Cell Populations

Despite the environmental constraints imposed upon the intestinal epithelium, this tissue must perform essential functions such as nutrient absorption and hormonal regulation, while also acting as a critical barrier to the outside world. These functions depend on a variety of specialized cell types that are constantly renewed by a rapidly proliferating population of intestinal stem cells (ISCs) residing at the base of the crypts of Lieberkühn. The niche components and signals regulating crypt morphogenesis and maintenance of homeostatic ISCs have been intensely studied over the last decades. Increasingly, however, researchers are turning their attention to unraveling the mechanisms driving gut epithelial regeneration due to physical damage or infection. It is now well established that injury to the gut barrier triggers major cell fate changes, demonstrating the highly plastic nature of the gut epithelium. In particular, lineage tracing and transcriptional profiling experiments have uncovered several injury-induced stem-cell populations and molecular markers of the regenerative state. Despite the progress achieved in recent years, several questions remain unresolved, particularly regarding the mechanisms driving dedifferentiation of the gut epithelium. In this review, we summarize the latest studies, primarily from murine models, that define the regenerative processes governing the gut epithelium and discuss areas that will require more in-depth investigation.

scholarly journals Hormonal Regulation of Stem Cell Proliferation at the Arabidopsis thaliana Root Stem Cell Niche

2021 ◽  
Vol 12 ◽  
Author(s):  
Mónica L. García-Gómez ◽  
Adriana Garay-Arroyo ◽  
Berenice García-Ponce ◽  
María de la Paz Sánchez ◽  
Elena R. Álvarez-Buylla
Keyword(s):  
Cell Proliferation ◽  
Arabidopsis Thaliana ◽  
Stem Cell ◽  
Cell Fate ◽  
Regulatory Network ◽  
Hormonal Regulation ◽  
Stem Cell Niche ◽  
Quiescent Center ◽  
Root Stem Cell ◽  
Cell Niche

The root stem cell niche (SCN) of Arabidopsis thaliana consists of the quiescent center (QC) cells and the surrounding initial stem cells that produce progeny to replenish all the tissues of the root. The QC cells divide rather slowly relative to the initials, yet most root tissues can be formed from these cells, depending on the requirements of the plant. Hormones are fundamental cues that link such needs with the cell proliferation and differentiation dynamics at the root SCN. Nonetheless, the crosstalk between hormone signaling and the mechanisms that regulate developmental adjustments is still not fully understood. Developmental transcriptional regulatory networks modulate hormone biosynthesis, metabolism, and signaling, and conversely, hormonal responses can affect the expression of transcription factors involved in the spatiotemporal patterning at the root SCN. Hence, a complex genetic–hormonal regulatory network underlies root patterning, growth, and plasticity in response to changing environmental conditions. In this review, we summarize the scientific literature regarding the role of hormones in the regulation of QC cell proliferation and discuss how hormonal signaling pathways may be integrated with the gene regulatory network that underlies cell fate in the root SCN. The conceptual framework we present aims to contribute to the understanding of the mechanisms by which hormonal pathways act as integrators of environmental cues to impact on SCN activity.

Two independent and polarized processes of cell elongation regulate leaf blade expansion in Arabidopsis thaliana (L.) Heynh

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1589-1600 ◽  
Author(s):  
T. Tsuge ◽  
H. Tsukaya ◽  
H. Uchimiya
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Elongation ◽  
Leaf Development ◽  
Cellular Level ◽  
Leaf Length ◽  
Specific Cell ◽  
Wild Type ◽  
Leaf Morphogenesis ◽  
Length Direction ◽  
Number Of Cells

For genetic analysis of mechanisms of leaf morphogenesis, we chose Arabidopsis thaliana (L.) Heynh. as a model for leaf development in dicotyledonous plants. Leaves of the angustifolia mutant were the same length as but narrower and thicker than wild-type leaves. The total number of cells in leaf blades of angustifolia plants was the same as in the wild type. At the cellular level in the angustifolia mutant it was found that the cells were smaller in the leaf-width direction and larger in the leaf-thickness direction than in wild type, revealing the function of the ANGUSTIFOLIA gene, which is to control leaf morphology by regulating polarity-specific cell elongation. The existence of similar genes that regulate leaf development in the length direction was, therefore, predicted. Three loci and several alleles associated with short-leaved mutants were newly isolated as rotundifolia mutants. The rotundifolia3 mutant had the same number of cells as the wild type, with reduced cell elongation in the leaf-length direction. The features of the angustifolia rotundifolia3 double mutant indicated that ANGUSTIFOLIA and ROTUNDIFOLIA3 genes act independently. We propose that leaf expansion in Arabidopsis involves at least two independent developmental processes: width development and length development, with the ANGUSTIFOLIA and ROTUNDIFOLIA3 genes playing different polarity-specific roles in cell elongation.

Epidermal induction and inhibition of neural fate by translation initiation factor 4AIII

Development ◽  
1997 ◽  
Vol 124 (21) ◽  
pp. 4235-4242
Author(s):  
D.C. Weinstein ◽  
E. Honore ◽  
A. Hemmati-Brivanlou
Keyword(s):  
Cell Fate ◽  
Translation Initiation ◽  
Mrna Translation ◽  
Bmp Signaling ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Neural Fate ◽  
Morphogenetic Protein ◽  
Dissociated Cells ◽  
A Site

Bone Morphogenetic Protein-4 (BMP-4) is a potent epidermal inducer and inhibitor of neural fate. We have used differential screening to identify genes involved in epidermal induction downstream of BMP-4 and report here evidence of a novel translational mechanism that regulates the division of the vertebrate ectoderm into regions of neural and epidermal fate. In dissociated Xenopus ectoderm, addition of ectopic BMP-4 leads to an increase in the expression of translation initiation factor 4AIII (eIF-4AIII), a divergent member of the eIF-4A gene family until now characterized only in plants. In the gastrula embryo, Xenopus eIF-4AIII (XeIF-4AIII) expression is elevated in the ventral ectoderm, a site of active BMP signal transduction. Moreover, overexpression of XeIF-4AIII induces epidermis in dissociated cells that would otherwise adopt a neural fate, mimicking the effects of BMP-4. Epidermal induction by XeIF-4AIII requires both an active BMP signaling pathway and an extracellular intermediate. Our results suggest that XeIF-4AIII can regulate changes in cell fate through selective mRNA translation. We propose that BMPs and XeIF-4AIII interact through a positive feedback loop in the ventral ectoderm of the vertebrate gastrula.

scholarly journals Coordination of Leaf Development Across Developmental Axes

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 433 ◽  
Author(s):  
James W. Satterlee ◽  
Michael J. Scanlon
Keyword(s):  
Leaf Development ◽  
Molecular Genetic ◽  
Transcriptional Network ◽  
Cell Type ◽  
Leaf Morphogenesis ◽  
Apical Meristems ◽  
Shoot Apical Meristems ◽  
Developmental Patterning ◽  
Genetic Mechanisms ◽  
Type Specification

Leaves are initiated as lateral outgrowths from shoot apical meristems throughout the vegetative life of the plant. To achieve proper developmental patterning, cell-type specification and growth must occur in an organized fashion along the proximodistal (base-to-tip), mediolateral (central-to-edge), and adaxial–abaxial (top-bottom) axes of the developing leaf. Early studies of mutants with defects in patterning along multiple leaf axes suggested that patterning must be coordinated across developmental axes. Decades later, we now recognize that a highly complex and interconnected transcriptional network of patterning genes and hormones underlies leaf development. Here, we review the molecular genetic mechanisms by which leaf development is coordinated across leaf axes. Such coordination likely plays an important role in ensuring the reproducible phenotypic outcomes of leaf morphogenesis.

scholarly journals Specification of adaxial cell fate during maize leaf development

Development ◽  
2004 ◽  
Vol 131 (18) ◽  
pp. 4533-4544 ◽  
Author(s):  
M. T. Juarez
Keyword(s):  
Cell Fate ◽  
Leaf Development ◽  
Maize Leaf

scholarly journals In-phase oscillation of global regulons is orchestrated by a pole-specific organizer

2016 ◽  
Vol 113 (44) ◽  
pp. 12550-12555 ◽  
Author(s):  
Balaganesh Janakiraman ◽  
Johann Mignolet ◽  
Sharath Narayanan ◽  
Patrick H. Viollier ◽  
Sunish Kumar Radhakrishnan
Keyword(s):  
Cell Cycle ◽  
Cell Fate ◽  
Caulobacter Crescentus ◽  
Transcriptional Regulators ◽  
Forward Genetics ◽  
Cell Fate Determination ◽  
Global Regulator ◽  
Site Specific ◽  
Phase Oscillation ◽  
A Site

Cell fate determination in the asymmetric bacteriumCaulobacter crescentus(Caulobacter) is triggered by the localization of the developmental regulator SpmX to the old (stalked) cell pole during the G1→S transition. Although SpmX is required to localize and activate the cell fate-determining kinase DivJ at the stalked pole inCaulobacter, in cousins such asAsticcacaulis, SpmX directs organelle (stalk) positioning and possibly other functions. We define the conserved σ54-dependent transcriptional activator TacA as a global regulator inCaulobacterwhose activation by phosphorylation is indirectly down-regulated by SpmX. Using a combination of forward genetics and cytological screening, we uncover a previously uncharacterized and polarized component (SpmY) of the TacA phosphorylation control system, and we show that SpmY function and localization are conserved. Thus, SpmX organizes a site-specific, ancestral, and multifunctional regulatory hub integrating the in-phase oscillation of two global transcriptional regulators, CtrA (the master cell cycle transcriptional regulator A) and TacA, that perform important cell cycle functions.

Temperature-sensitive mutations that arrest Arabidopsis shoot development

Development ◽  
1996 ◽  
Vol 122 (12) ◽  
pp. 3799-3807 ◽  
Author(s):  
F.B. Pickett ◽  
M.M. Champagne ◽  
D.R. Meeks-Wagner
Keyword(s):  
Apical Meristem ◽  
Shoot Development ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Normal Leaf ◽  
Temperature Dependent ◽  
Leaf Morphogenesis ◽  
Developmental Defects ◽  
Leaf Initiation ◽  
Reduced Rate

To identify genes involved in meristem function we have designed a screen for temperature-sensitive mutations that cause a conditional arrest of early shoot development in Arabidopsis. We describe the characterization of three mutations, arrested development (add) 1, 2 and 3. At the restrictive temperature the add1 and add2 mutations disrupt apical meristem function as assayed by leaf initiation. Furthermore, add1 and add2 plants exhibit defects in leaf morphogenesis following upshift from permissive to restrictive temperature. This result suggests that proximity to a functional meristem is required for the completion of normal leaf morphogenesis. The add3 mutation does not have a dramatic effect on the production of leaves by the apical meristem; however, add3 prevents the expansion of leaf blades at high temperature. Thus, in this mutant the temperature-dependent arrest of epicotyl development is due to a failure of normal leaf development rather than new leaf initiation. While all add mutants have a reduced rate of root growth in comparison to wild-type plants, the mutants do not display a temperature-dependent arrest of root development. All add mutants display some developmental defects at low temperature, suggesting that these mutations affect genes involved in inherently temperature-sensitive developmental processes.

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