Embryonic origin of the Arabidopsis primary root and root meristem initials

Development ◽  
1994 ◽  
Vol 120 (9) ◽  
pp. 2475-2487 ◽  
Author(s):  
B. Scheres ◽  
H. Wolkenfelt ◽  
V. Willemsen ◽  
M. Terlouw ◽  
E. Lawson ◽  
...  
Keyword(s):  
Root Meristem ◽  
Marker Gene ◽  
Primary Root ◽  
Cortical Cell ◽  
Fate Map ◽  
Cell Region ◽  
End Points ◽  
Histological Techniques ◽  
Cell Lineages ◽  
Embryonic Origin

The embryonic origin of the Arabidopsis root and hypocotyl region has been investigated using histological techniques and clonal analysis. Our data reveal the pattern of cell division in the embryo giving rise to the various initials within the root promeristem. A small region of the root at its connection with the hypocotyl appears not to be derived from the promeristem initials. This region contains two cortical cell layer and [3H]thymidine incorporation data suggest that it lacks postembryonic cell divisions. Sectors marked by transposon excision from the beta-glucuronidase marker gene are used to investigate cell lineages giving rise to root and hypocotyl. The position of end points from sectors with embryonic origin show little variation and hence reveal preferred positions in the seedling for cells derived from different regions of the embryo. The radial extent of complete root sectors is consistent with the radial arrangement of root meristem initials at the heart stage of embryogenesis inferred from histological analysis. Using the clonal data, a fate map is constructed depicting the destiny of heart stage embryonic cell tiers, in the seedling root and hypocotyl. The variability in the sector end points indicates that distinct cell lineages are not restricted for root or hypocotyl fate. In contrast, derivatives of the hypophyseal cell do appear to be restricted to the columella and central cell region of the root.

Cell movements and cell fate during zebrafish gastrulation

Development ◽  
1992 ◽  
Vol 116 (Supplement) ◽  
pp. 65-73 ◽  
Author(s):  
Robert K. Ho
Keyword(s):  
Single Cell ◽  
Cell Fate ◽  
Fate Map ◽  
Cell Fates ◽  
Cell Lineages ◽  
Cell Position ◽  
Vertebrate Embryo ◽  
Cellular Identity ◽  
Transplantation Experiments

The early lineages of the zebrafish are indeterminate and a single cell labeled before the late blastula period will contribute progeny to a variety of tissues. Therefore, early cell lineages in the zebrafish do not establish future cell fates and early blastomeres must necessarily remain pluripotent. Eventually, after a period of random cell mixing, individual cells do become tissue restricted according to their later position within the blastoderm. The elucidation of a fate map for the zebrafish gastrula (Kimmel et al., 1990), has made it possible to study the processes by which cellular identity is conferred and maintained in the zebrafish. In this chapter, I describe single cell transplantation experiments designed to test for the irreversible restriction or ‘commitment’ of embryonic blastomeres in the zebrafish embryo. These experiments support the hypothesis that cell fate in the vertebrate embryo is determined by cell position. Work on the spadetail mutation will also be reviewed; this mutation causes a subset of mesodermal precursors to mismigrate during gastrulation thereby leading to a change in their eventual cell identity.

scholarly journals Unraveling the embryonic fate map through the mechanical signature of cells and their trajectories

2021 ◽  
Author(s):  
David Pastor-Escuredo ◽  
Benoit Lombardot ◽  
Thierry Savy ◽  
Adeline Adeline Boyreau ◽  
Rene Doursat ◽  
...  
Keyword(s):  
Deformation Rate ◽  
Phenotypic Variability ◽  
Early Developmental Stage ◽  
Embryonic Cells ◽  
Imaging Data ◽  
Fate Map ◽  
Cell Lineages ◽  
Multi Scale ◽  
Mesoscopic Level ◽  
Cumulative Deformation

Abstract Digital cell lineages reconstructed from 3D+time imaging data of the developing zebrafish embryo are used to uncover mechanical cues and their role in morphogenesis. A continuous approximation of cell displacements obtained from cell lineages is used to assess tissue deformation during gastrulation. At this stage, embryonic tissues display multi-scale compressible fluid-like properties. The deformation rate at the mesoscopic level of the cell’s immediate surroundings appears noisy, in both space and time. The patterns identified by clustering the cells, according to the cumulative deformation rate along their trajectory throughout gastrulation, lead to a robust, ordered and coherent biomechanical map. The timing and amplitude of the biomechanical deformations provide a measurement of the phenotypic variability in small cohorts of specimens. We show that the biomechanical map matches the embryonic fate map of the zebrafish presumptive forebrain, in both wild type and Nodal pathway mutants (zoeptz57/tz57), where it reveals the biomechanical defects that lead to cyclopia.. The comparison of biomechanical patterns and the expression pattern of a transgenic reporter for the transcription factor goosecoid (gsc), supports the hypothesis that embryonic cells acquire, at an early developmental stage, a biomechanical signature that contributes to defining their fate.

Morphological and Histochemical Studies of Primary Root Meristem of Rauwolfia vomitoria

1965 ◽  
Vol 126 (3) ◽  
pp. 204-208 ◽  
Author(s):  
Abdul J. Mia ◽  
Suman M. Pathak
Keyword(s):  
Root Meristem ◽  
Primary Root ◽  
Rauwolfia Vomitoria

The auxin-insensitive bodenlos mutation affects primary root formation and apical-basal patterning in the Arabidopsis embryo

Development ◽  
1999 ◽  
Vol 126 (7) ◽  
pp. 1387-1395 ◽  
Author(s):  
T. Hamann ◽  
U. Mayer ◽  
G. Jurgens
Keyword(s):  
Daughter Cell ◽  
Root Formation ◽  
Normal Development ◽  
Root Meristem ◽  
Primary Root ◽  
Cell Stage ◽  
New Gene ◽  
Auxin Resistant1 ◽  
Auxin Analogue ◽  
Adult Plants

In Arabidopsis embryogenesis, the primary root meristem originates from descendants of both the apical and the basal daughter cell of the zygote. We have isolated a mutant of a new gene named BODENLOS (BDL) in which the primary root meristem is not formed whereas post-embryonic roots develop and bdl seedlings give rise to fertile adult plants. Some bdl seedlings lacked not only the root but also the hypocotyl, thus resembling monopteros (mp) seedlings. In addition, bdl seedlings were insensitive to the auxin analogue 2,4-D, as determined by comparison with auxin resistant1 (axr1) seedlings. bdl embryos deviated from normal development as early as the two-cell stage at which the apical daughter cell of the zygote had divided horizontally instead of vertically. Subsequently, the uppermost derivative of the basal daughter cell, which is normally destined to become the hypophysis, divided abnormally and failed to generate the quiescent centre of the root meristem and the central root cap. We also analysed double mutants. bdl mp embryos closely resembled the two single mutants, bdl and mp, at early stages, while bdl mp seedlings essentially consisted of hypocotyl but did form primary leaves. bdl axr1 embryos approached the mp phenotype at later stages, and bdl axr1 seedlings resembled mp seedlings. Our results suggest that BDL is involved in auxin-mediated processes of apical-basal patterning in the Arabidopsis embryo.

scholarly journals ARF5/MONOPTEROS directly regulates miR390 expression in the Arabidopsis thaliana primary root meristem

Plant Direct ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. e00116 ◽  
Author(s):  
Mouli Ghosh Dastidar ◽  
Andrea Scarpa ◽  
Ira Mägele ◽  
Paola Ruiz-Duarte ◽  
Patrick von Born ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Meristem ◽  
Primary Root

Origin and organization of the zebrafish fate map

Development ◽  
1990 ◽  
Vol 108 (4) ◽  
pp. 581-594 ◽  
Author(s):  
C.B. Kimmel ◽  
R.M. Warga ◽  
T.F. Schilling
Keyword(s):  
Deep Layer ◽  
Cell Types ◽  
Fate Map ◽  
Animal Pole ◽  
Amphibian Embryo ◽  
Yolk Cell ◽  
Cell Lineages ◽  
Embryonic Tissues ◽  
Dorsal Cells ◽  
Early Gastrula

We have analyzed lineages of cells labeled by intracellular injection of tracer dye during early zebrafish development to learn when cells become allocated to particular fates during development, and how the fate map is organized. The earliest lineage restriction was described previously, and segregates the yolk cell from the blastoderm in the midblastula. After one or two more cell divisions, the lineages of epithelial enveloping layer (EVL) cells become restricted to generate exclusively periderm. Following an additional division in the late blastula, deep layer (DEL) cells generate clones that are restricted to single deep embryonic tissues. The appearance of both the EVL and DEL restrictions could be causally linked to blastoderm morphogenesis during epiboly. A fate map emerges as the DEL cell lineages become restricted in the late blastula. It is similar in organization to that of an amphibian embryo. DEL cells located near the animal pole of the early gastrula give rise to ectodermal fates (including the definitive epidermis). Cells located near the blastoderm margin give rise to mesodermal and endodermal fates. Dorsal cells in the gastrula form dorsal and anterior structures in the embryo, and ventral cells in the gastrula form dorsal, ventral and posterior structures. The exact locations of progenitors of single cell types and of local regions of the embryo cannot be mapped at the stages we examined, because of variable cell rearrangements during gastrulation.

Cellular organisation of the Arabidopsis thaliana root

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 71-84 ◽  
Author(s):  
L. Dolan ◽  
K. Janmaat ◽  
V. Willemsen ◽  
P. Linstead ◽  
S. Poethig ◽  
...  
Keyword(s):  
Lateral Roots ◽  
Primary Root ◽  
Mature Embryo ◽  
Cell Number ◽  
Root Cap ◽  
Developmental Genetics ◽  
Histological Techniques ◽  
Transmission Electron ◽  
Root Morphogenesis ◽  
Future Work

The anatomy of the developing root of Arabidopsis is described using conventional histological techniques, scanning and transmission electron microscopy. The root meristem is derived from cells of the hypophysis and adjacent cells of the embryo proper. The postembryonic organization of the root is apparent in the mature embryo and is maintained in the growing primary root after germination. Cell number and location is relatively invariant in the primary root, with 8 cortical and endodermal cell files but more variable numbers of pericycle and epidermal cells. The organisation of cells in lateral roots is similar to that of the primary root but with more variability in the numbers of cell files in each layer. [3H]thymidine labeling of actively growing roots indicates that a quiescent centre of four central cells (derived from the hypophysis) is located between the root cap columella and the stele. This plate of four cells is surrounded by three groups of cells in, proximal, distal and lateral positions. The labeling patterns of these cells suggest that they are the initials for the files of cells that comprise the root. They give rise to four sets of cell files: the stele, the cortex and endodermis, the epidermis and lateral root-cap and the columella. A model of meristem activity is proposed based on these data. This description of Arabidopsis root structure underpins future work on the developmental genetics of root morphogenesis.

Mutations affecting the radial organisation of the Arabidopsis root display specific defects throughout the embryonic axis

Development ◽  
1995 ◽  
Vol 121 (1) ◽  
pp. 53-62 ◽  
Author(s):  
B. Scheres ◽  
L. Di Laurenzio ◽  
V. Willemsen ◽  
M. T. Hauser ◽  
K. Janmaat ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Vascular Tissue ◽  
Root Meristem ◽  
Primary Root ◽  
Cell Types ◽  
Embryonic Axis ◽  
Arabidopsis Root ◽  
Radial Pattern ◽  
Secondary Roots ◽  
Mature Root

The primary root of Arabidopsis thaliana has a remarkably uniform cellular organisation. The fixed radial pattern of cell types in the mature root arises from proliferative divisions within the root meristem. The root meristem, in turn, is laid down during embryogenesis. We have analysed six mutations causing alterations in the radial organisation of the root. Embryonic phenotypes resulting from wooden leg, gollum, pinocchio, scarecrow, shortroot and fass mutations are described. While mutations in the fass gene affect morphogenesis of all cells, the five other mutations cause alterations in specific layers. Wooden leg and gollum mutations interfere with the proper organisation of the vascular tissue. Shortroot, scarecrow and pinocchio affect the endodermis and cortex. The layer- specific phenotypes caused by all five mutations are also apparent in the hypocotyl. All these phenotypes originate from defects in the radial organisation of the embryonic axis. Secondary roots, which are formed post-embryonically, also display layer-specific phenotypes.

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