scholarly journals Decision letter: Mechanical stress contributes to the expression of the STM homeobox gene in Arabidopsis shoot meristems

2015 ◽  
Keyword(s):  
Mechanical Stress ◽  
Homeobox Gene ◽  
Shoot Meristems

scholarly journals Author response: Mechanical stress contributes to the expression of the STM homeobox gene in Arabidopsis shoot meristems

2015 ◽  
Author(s):  
Benoît Landrein ◽  
Annamaria Kiss ◽  
Massimiliano Sassi ◽  
Aurélie Chauvet ◽  
Pradeep Das ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Homeobox Gene ◽  
Author Response ◽  
Shoot Meristems

scholarly journals Mechanical stress contributes to the expression of the STM homeobox gene in Arabidopsis shoot meristems

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Benoît Landrein ◽  
Annamaria Kiss ◽  
Massimiliano Sassi ◽  
Aurélie Chauvet ◽  
Pradeep Das ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Homeobox Gene ◽  
Master Regulator ◽  
Cell Identity ◽  
Auxin Distribution ◽  
Mechanical Signals ◽  
Shoot Meristems

The role of mechanical signals in cell identity determination remains poorly explored in tissues. Furthermore, because mechanical stress is widespread, mechanical signals are difficult to uncouple from biochemical-based transduction pathways. Here we focus on the homeobox gene SHOOT MERISTEMLESS (STM), a master regulator and marker of meristematic identity in Arabidopsis. We found that STM expression is quantitatively correlated to curvature in the saddle-shaped boundary domain of the shoot apical meristem. As tissue folding reflects the presence of mechanical stress, we test and demonstrate that STM expression is induced after micromechanical perturbations. We also show that STM expression in the boundary domain is required for organ separation. While STM expression correlates with auxin depletion in this domain, auxin distribution and STM expression can also be uncoupled. STM expression and boundary identity are thus strengthened through a synergy between auxin depletion and an auxin-independent mechanotransduction pathway at the shoot apical meristem.

Control of phyllotaxy in maize by the abphyl1 gene

Development ◽  
1999 ◽  
Vol 126 (2) ◽  
pp. 315-323 ◽  
Author(s):  
D. Jackson ◽  
S. Hake
Keyword(s):  
Apical Meristem ◽  
General Structure ◽  
Homeobox Gene ◽  
The Other ◽  
Shoot Meristem ◽  
Regular Pattern ◽  
Expression Domain ◽  
Geometric Patterns ◽  
Maize Plants ◽  
Shoot Meristems

Organogenesis in plants occurs at the shoot apical meristem, a group of indeterminate stem cells that are organized during embryogenesis. Regulated initiation of leaves or flowers from the shoot meristem gives rise to the familiar geometric patterns observed throughout the plant kingdom. The mechanism by which these patterns, termed phyllotaxies, are generated, remains unclear. Maize plants initiate leaves singly, alternating from one side to the other in a regular pattern. Here we describe a recessive maize mutant, abphyl1, that initiates leaves in opposite pairs, in a pattern termed decussate phyllotaxy. The decussate shoot meristems are larger than normal throughout development, though the general structure and organization of the meristem is not altered. abph1 mutants are first distinguished during embryogenesis, prior to true leaf initiation, by a larger shoot meristem and coincident larger expression domain of the homeobox gene knotted1. Therefore, the abph1 gene regulates morphogenesis in the embryo, and plays a role in determining the phyllotaxy of the shoot.

scholarly journals Loss-of-function mutations in the maize homeobox gene, knotted1, are defective in shoot meristem maintenance

Development ◽  
1997 ◽  
Vol 124 (16) ◽  
pp. 3045-3054 ◽  
Author(s):  
R.A. Kerstetter ◽  
D. Laudencia-Chingcuanco ◽  
L.G. Smith ◽  
S. Hake
Keyword(s):  
Homeobox Gene ◽  
Leaf Primordia ◽  
Shoot Meristem ◽  
Loss Of Function ◽  
Floral Organs ◽  
Leaf Phenotype ◽  
Lateral Organ ◽  
Recessive Mutant ◽  
Meristem Maintenance ◽  
Shoot Meristems

The product of the maize homeobox gene, knotted1 (kn1), localizes to the nuclei of cells in shoot meristems, but is absent from portions of the meristem where leaf primordia or floral organs initiate. Recessive mutant alleles of kn1 were obtained by screening for loss of the dominant leaf phenotype in maize. Mutant kn1 alleles carrying nonsense, splicing and frame shift mutations cause severe inflorescence and floral defects. Mutant tassels produce fewer branches and spikelets. Ears are often absent, and when present, are small with few spikelets. In addition, extra carpels form in female florets and ovule tissue proliferates abnormally. Less frequently, extra leaves form in the axils of vegetative leaves. These mutations reveal a role for kn1 in meristem maintenance, particularly as it affects branching and lateral organ formation.

scholarly journals Expression of maize KNOTTED1 related homeobox genes in the shoot apical meristem predicts patterns of morphogenesis in the vegetative shoot

Development ◽  
1994 ◽  
Vol 120 (2) ◽  
pp. 405-413 ◽  
Author(s):  
D. Jackson ◽  
B. Veit ◽  
S. Hake
Keyword(s):  
Shoot Apical Meristem ◽  
Leaf Development ◽  
Apical Meristem ◽  
Expression Patterns ◽  
Homeobox Genes ◽  
Homeobox Gene ◽  
Vegetative Shoot ◽  
Lateral Organs ◽  
Floral Meristems ◽  
Shoot Meristems

In this paper we describe the expression patterns of a family of homeobox genes in maize and their relationship to organogenic domains in the vegetative shoot apical meristem. These genes are related by sequence to KNOTTED1, a gene characterized by dominant neomorphic mutations which perturb specific aspects of maize leaf development. Four members of this gene family are expressed in shoot meristems and the developing stem, but not in determinate lateral organs such as leaves or floral organs. The genes show distinct expression patterns in the vegetative shoot apical meristem that together predict the site of leaf initiation and the basal limit of the vegetative ‘phytomer’ or segmentation unit of the shoot. These genes are also expressed in the inflorescence and floral meristems, where their patterns of expression are more similar, and they are not expressed in root apical meristems. These findings are discussed in relation to other studies of shoot apical meristem organization as well as possible commonality of homeobox gene function in the animal and plant kingdoms.

Homeobox genes in the functioning of plant meristems

1995 ◽  
Vol 350 (1331) ◽  
pp. 45-51 ◽  
Keyword(s):  
Molecular Markers ◽  
Gene Family ◽  
Leaf Morphology ◽  
Ectopic Expression ◽  
Homeobox Gene ◽  
Positional Information ◽  
Specific Expression ◽  
Tobacco Leaf ◽  
Floral Meristems ◽  
Shoot Meristems

The maize homeobox gene knotted1 ( kn1 ) is expressed in vegetative and floral meristems and is down-regulated at the site of primordia formation. kn1 -related genes from maize and other species also show meristem-specific expression and offer additional tools for studying the activities of shoot meristems. Members of this gene family are expressed early in embryogenesis, providing molecular markers for meristem initiation. Ectopic expression of either kn1 or a related Arabidopsis gene, KNAT1 , causes dramatic alterations in Arabidopsis and tobacco leaf morphology. Most significantly, meristems form on the leaf, producing small shoots. We discuss whether the phenotypes can be interpreted as changes in positional information or timing of determination.

Ectopic expression of the maize kn1 gene phenocopies the Hooded mutant of barley

Development ◽  
1997 ◽  
Vol 124 (19) ◽  
pp. 3737-3745 ◽  
Author(s):  
R.E. Williams-Carrier ◽  
Y.S. Lie ◽  
S. Hake ◽  
P.G. Lemaux
Keyword(s):  
Expression Pattern ◽  
Posttranscriptional Regulation ◽  
Cellular Differentiation ◽  
Ectopic Expression ◽  
Homeobox Gene ◽  
Mrna Localization ◽  
Constitutive Promoter ◽  
Homeotic Transformation ◽  
Shoot Meristems

The homeobox gene, knotted1, (kn1) is expressed in shoot meristems and is required for maintaining indeterminacy and preventing cellular differentiation. Awns, extensions of the bract-like lemma found in all grass inflorescences, are normally determinate structures. We show that ectopic expression of kn1 in the barley awn is sufficient to direct the development of ectopic meristems, forming inflorescence-like structures. This homeotic transformation is similar to the phenotype produced by misexpression of the barley hvknox3 gene, associated with the dominant Hooded mutant (Muller, K. J., Romano, N., Gerstner, O., Garcia-Maroto, F., Pozzi, C., Salamini, F. and Rohde, W. (1995) Nature 374, 727–730). We suggest that the inverse polarity of the ectopic flowers seen in Hooded and transgenic kn1 plants results from the transformation of the awn into reiterative inflorescence axes. We observed that the protein and mRNA localization of the transgene, driven by a constitutive promoter, is similar to the expression pattern of hvknox3 in awns of Hooded mutants, suggesting posttranscriptional regulation.

Behaviour of Ni-Mn-Ga alloys under mechanical stress

2003 ◽  
Vol 112 ◽  
pp. 943-946 ◽  
Author(s):  
K. Koho ◽  
J. Vimpari ◽  
L. Straka ◽  
N. Lanska ◽  
O. Sôderberg ◽  
...  
Keyword(s):  
Mechanical Stress
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