scholarly journals Regulation of Arabidopsis shoot apical meristem and lateral organ formation by microRNA miR166g and its AtHD-ZIP target genes

Development ◽  
2005 ◽  
Vol 132 (16) ◽  
pp. 3657-3668 ◽  
Author(s):  
L. Williams
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Target Genes ◽  
Organ Formation ◽  
Lateral Organ

scholarly journals FAR-RED ELONGATED HYPOCOTYL3 activates SEPALLATA2 but inhibits CLAVATA3 to regulate meristem determinacy and maintenance in Arabidopsis

2016 ◽  
Vol 113 (33) ◽  
pp. 9375-9380 ◽  
Author(s):  
Dongming Li ◽  
Xing Fu ◽  
Lin Guo ◽  
Zhigang Huang ◽  
Yongpeng Li ◽  
...  
Keyword(s):  
Flower Development ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Target Genes ◽  
Developmental Stages ◽  
Binding Motif ◽  
Phytochrome B ◽  
Helix Loop Helix ◽  
Before And After ◽  
Meristem Maintenance

Plant meristems are responsible for the generation of all plant tissues and organs. Here we show that the transcription factor (TF) FAR-RED ELONGATED HYPOCOTYL3 (FHY3) plays an important role in both floral meristem (FM) determinacy and shoot apical meristem maintenance in Arabidopsis, in addition to its well-known multifaceted roles in plant growth and development during the vegetative stage. Through genetic analyses, we show that WUSCHEL (WUS) and CLAVATA3 (CLV3), two central players in the establishment and maintenance of meristems, are epistatic to FHY3. Using genome-wide ChIP-seq and RNA-seq data, we identify hundreds of FHY3 target genes in flowers and find that FHY3 mainly acts as a transcriptional repressor in flower development, in contrast to its transcriptional activator role in seedlings. Binding motif-enrichment analyses indicate that FHY3 may coregulate flower development with three flower-specific MADS-domain TFs and four basic helix–loop–helix TFs that are involved in photomorphogenesis. We further demonstrate that CLV3, SEPALLATA1 (SEP1), and SEP2 are FHY3 target genes. In shoot apical meristem, FHY3 directly represses CLV3, which consequently regulates WUS to maintain the stem cell pool. Intriguingly, CLV3 expression did not change significantly in fhy3 and phytochrome B mutants before and after light treatment, indicating that FHY3 and phytochrome B are involved in light-regulated meristem activity. In FM, FHY3 directly represses CLV3, but activates SEP2, to ultimately promote FM determinacy. Taken together, our results reveal insights into the mechanisms of meristem maintenance and determinacy, and illustrate how the roles of a single TF may vary in different organs and developmental stages.

scholarly journals Organogenesis at the Shoot Apical Meristem

Plants ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 6 ◽  
Author(s):  
Jan Traas
Keyword(s):  
Cell Wall ◽  
Growth Rates ◽  
Shoot Apical Meristem ◽  
Regulatory Network ◽  
Apical Meristem ◽  
Major Elements ◽  
Cellulose Microfibrils ◽  
Wall Structure ◽  
Structural Elements ◽  
Lateral Organ

Lateral organ initiation at the shoot apical meristem involves complex changes in growth rates and directions, ultimately leading to the formation of leaves, stems and flowers. Extensive molecular analysis identifies auxin and downstream transcriptional regulation as major elements in this process. This molecular regulatory network must somehow interfere with the structural elements of the cell, in particular the cell wall, to induce specific morphogenetic events. The cell wall is composed of a network of rigid cellulose microfibrils embedded in a matrix composed of water, polysaccharides such as pectins and hemicelluloses, proteins, and ions. I will discuss here current views on how auxin dependent pathways modulate wall structure to set particular growth rates and growth directions. This involves complex feedbacks with both the cytoskeleton and the cell wall.

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 ASYMMETRIC LEAVES1 reveals knox gene redundancy in Arabidopsis

Development ◽  
2002 ◽  
Vol 129 (8) ◽  
pp. 1957-1965 ◽  
Author(s):  
Mary E. Byrne ◽  
Joseph Simorowski ◽  
Robert A. Martienssen
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Cell Function ◽  
The Novel ◽  
Knox Gene ◽  
Knox Genes ◽  
Lateral Organs ◽  
Gene Redundancy ◽  
Lateral Organ ◽  
Meristem Maintenance

The shoot apical meristem comprises undifferentiated stem cells and their derivatives, which include founder cells for lateral organs such as leaves. Meristem maintenance and lateral organ specification are regulated in part by negative interactions between the myb domain transcription factor ASYMMETRIC LEAVES1, which is expressed in lateral organ primordia, and homeobox transcription factors which are expressed in the shoot apical meristem (knox genes). The knox gene SHOOT MERISTEMLESS (STM) negatively regulates ASYMMETRIC LEAVES1 (AS1) which, in turn, negatively regulates other knox genes including KNAT1 and KNAT2, and positively regulates the novel gene LATERAL ORGAN BOUNDARIES (LOB). Genetic interactions with a second gene, ASYMMETRIC LEAVES2 (AS2), indicate it acts at the same position in this hierarchy as AS1. We have used a second-site suppressor screen to isolate mutations in KNAT1 and we show that KNAT1 is partially redundant with STM in regulating stem cell function. Mutations in KNAT2 show no such interaction. We discuss the regulation and evolution of redundancy among knox genes.

scholarly journals Sample preparation for laser-microdissection of soybean shoot apical meristem

2012 ◽  
Vol 3 (1) ◽  
pp. 3 ◽  
Author(s):  
Chui E. Wong ◽  
Mohan B. Singh ◽  
Prem L. Bhalla
Keyword(s):  
Sample Preparation ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Laser Microdissection ◽  
Specific Cell ◽  
Legume Crop ◽  
Continuous Formation ◽  
Molecular Events ◽  
Depth Analysis ◽  
Specialized Equipment

The shoot apical meristem houses stem cells responsible for the continuous formation of aerial plant organs including leaves and stems throughout the life of plants. Laser-microdissection in combination with high-throughput technology such as next generation sequencing permits an in-depth analysis of molecular events associated with specific cell type of interest. Sample preparation is the most critical step in ensuring good quality RNA to be extracted from samples following laser-microdissection. Here, we optimized the sample preparation for a major legume crop, soybean. We used Farmer’s solution as a fixative and paraffin as the embedding medium for soybean shoot apical meristem tissue without the use of any specialized equipment. Shorter time for tissue fixation (two days) was found to be critical for the preservation of RNA in soybean shoot apical meristem. We further demonstrated the utility of this method for different tissues derived from soybean and rice. The method outlined here shall facilitate studies on crop plants involving laser-microdissection.

Somatic embryogenesis from Arabidopsis shoot apical meristem mutants

Planta ◽  
2002 ◽  
Vol 214 (6) ◽  
pp. 829-836 ◽  
Author(s):  
Andreas Mordhorst ◽  
Marijke Hartog ◽  
Mazen El Tamer ◽  
Thomas Laux ◽  
Sacco de Vries
Keyword(s):  
Somatic Embryogenesis ◽  
Shoot Apical Meristem ◽  
Apical Meristem

scholarly journals Arabidopsis Argonaute10 Specifically Sequesters miR166/165 to Regulate Shoot Apical Meristem Development

Cell ◽  
2011 ◽  
Vol 145 (2) ◽  
pp. 242-256 ◽  
Author(s):  
Hongliang Zhu ◽  
Fuqu Hu ◽  
Ronghui Wang ◽  
Xin Zhou ◽  
Sing-Hoi Sze ◽  
...  
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Meristem Development

scholarly journals Spatiotemporal Sequestration of miR165/166 by Arabidopsis Argonaute10 Promotes Shoot Apical Meristem Maintenance

Cell Reports ◽  
2015 ◽  
Vol 10 (11) ◽  
pp. 1819-1827 ◽  
Author(s):  
Yuyi Zhou ◽  
Minami Honda ◽  
Hongliang Zhu ◽  
Zhonghui Zhang ◽  
Xinwei Guo ◽  
...  
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Meristem Maintenance
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