Trichome cell morphogenesis in Arabidopsis: a continuum of cellular decisionsThis review is one of a selection of papers published in the Special Issue on Plant Cell Biology.

2006 ◽  
Vol 84 (4) ◽  
pp. 604-612 ◽  
Author(s):  
Jaideep Mathur

In keeping with the myriad functions carried out by plants, their component cells display an amazing diversity of shapes and sizes. How is a precise cell form achieved? In recent years, the single-celled, branched, aerial epidermal trichome of Arabidopsis thaliana L. (Heynh) has emerged as a model cell for understanding the cell biological and molecular basis underlying the development of cell shape in plants. Here, I critique the recent information gleaned from dissecting trichome cell morphogenesis in Arabidopsis and identify areas and questions that can be further addressed using this unique cell type.

2006 ◽  
Vol 84 (4) ◽  
pp. 515-522 ◽  
Author(s):  
Preetinder K. Dhanoa ◽  
Alison M. Sinclair ◽  
Robert T. Mullen ◽  
Jaideep Mathur

The discovery and development of multicoloured fluorescent proteins has led to the exciting possibility of observing a remarkable array of subcellular structures and dynamics in living cells. This minireview highlights a number of the more common fluorescent protein probes in plants and is a testimonial to the fact that the plant cell has not lagged behind during the live-imaging revolution and is ready for even more in-depth exploration.


Development ◽  
1997 ◽  
Vol 124 (19) ◽  
pp. 3779-3786 ◽  
Author(s):  
U. Folkers ◽  
J. Berger ◽  
M. Hulskamp

Cell morphogenesis, i.e. the acquisition of a particular cell shape, can be examined genetically in the three-branched trichomes that differentiate from single epidermal cells on the leaves of Arabidopsis thaliana. In normal development, the growing trichome cell undergoes two successive branching events, resulting in a proximal side stem and a distal main stem which subsequently splits in two branches. Using new and previously described trichome mutants, we have analyzed the branching pattern in single and double mutants affecting branch number or cell size in order to determine underlying mechanisms. Our results suggest that primary branching is genetically distinct from subsequent branching events and that the latter, secondary events are initiated in response to positive and negative regulators of branching as well as subject to control by cell growth. We propose a model of how trichome cell morphogenesis is regulated during normal development.


2006 ◽  
Vol 84 (4) ◽  
pp. 651-667 ◽  
Author(s):  
Christopher P. Trobacher ◽  
Adriano Senatore ◽  
John S. Greenwood

Cysteine proteinases are ubiquitously involved in programmed cell death (PCD) in multicellular organisms. In animals, one group of cysteine proteinases, the cysteine-dependent aspartate-specific proteinases (caspases), are involved in a proteolytic signalling cascade that controls apoptosis, the most studied form of PCD. The enzymes act as both masterminds and executioners in apoptotic cell death. In plants, members of the metacaspase family, as well as those of the papain-like and legumain families, of cysteine proteinases have all been implicated in PCD. These enzymes often belong to sizeable gene families, with Arabidopsis having 9 metacaspase, 32 papain-like, and 4 legumain genes. This redundancy has made it difficult to ascertain the functional importance of any particular enzyme in plant PCD, as many are often expressed in a given tissue undergoing PCD. As yet, mechanisms similar to the apoptotic caspase cascade in animals have not been uncovered in plants and, indeed, may not exist. Are the various cysteine proteinases, so often implicated in plant PCD, merely acting as minions in the process? This review will outline reports of cysteine proteinases associated with plant PCD, discuss problems in determining the function of specific proteases, and suggest avenues for determining how these enzymes might be regulated and how PCD pathways upstream of protease expression and activation might operate.


eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Juan Tian ◽  
Libo Han ◽  
Zhidi Feng ◽  
Guangda Wang ◽  
Weiwei Liu ◽  
...  

Microtubules (MTs) and actin filaments (F-actin) function cooperatively to regulate plant cell morphogenesis. However, the mechanisms underlying the crosstalk between these two cytoskeletal systems, particularly in cell shape control, remain largely unknown. In this study, we show that introduction of the MyTH4-FERM tandem into KCBP (kinesin-like calmodulin-binding protein) during evolution conferred novel functions. The MyTH4 domain and the FERM domain in the N-terminal tail of KCBP physically bind to MTs and F-actin, respectively. During trichome morphogenesis, KCBP distributes in a specific cortical gradient and concentrates at the branching sites and the apexes of elongating branches, which lack MTs but have cortical F-actin. Further, live-cell imaging and genetic analyses revealed that KCBP acts as a hub integrating MTs and actin filaments to assemble the required cytoskeletal configuration for the unique, polarized diffuse growth pattern during trichome cell morphogenesis. Our findings provide significant insights into the mechanisms underlying cytoskeletal regulation of cell shape determination.


2006 ◽  
Vol 84 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Sally L. Hanton ◽  
Federica Brandizzi

The study of the plant secretory pathway is a relatively new field, developing rapidly over the last 30 years. Many exciting discoveries have already been made in this area, but as old questions are answered new ones become apparent. Our understanding of the functions and mechanisms of the plant secretory pathway is constantly expanding, in part because of the development of new technologies, mainly in bioimaging. The increasing accessibility of these new tools in combination with more established methods provides an ideal way to increase knowledge of the secretory pathway in plants. In this review we discuss recent developments in understanding protein transport between organelles in the plant secretory pathway.


2006 ◽  
Vol 84 (4) ◽  
pp. 531-542 ◽  
Author(s):  
Matthew D. Smith

Chloroplasts are but one type of a diverse group of essential organelles that distinguish plant cells and house many critical biochemical pathways, including photosynthesis. The biogenesis of plastids is essential to plant growth and development and relies on the targeting and import of thousands of nuclear-encoded proteins from the cytoplasm. The import of the vast majority of these proteins is dependent on translocons located in the outer and inner envelope membranes of the chloroplast, termed the Toc and Tic complexes, respectively. The core components of the Toc and Tic complexes have been identified within the last 12 years; however, the precise functions of many components are still being elucidated, and new components are still being identified. In Arabidopsis thaliana (and other species), many of the components are encoded by more than one gene, and it appears that the isoforms differentially associate with structurally distinct import complexes. Furthermore, it appears that these complexes represent functionally distinct targeting pathways, and the regulation of import by these separate pathways may play a role in the differentiation and specific functions of distinct plastid types during plant growth and development. This review summarizes these recent discoveries and emphasizes the mechanisms of differential Toc complex assembly and substrate recognition.


Biomaterials ◽  
2013 ◽  
Vol 34 (22) ◽  
pp. 5552-5561 ◽  
Author(s):  
Nathalie Groen ◽  
Jeroen van de Peppel ◽  
Huipin Yuan ◽  
Johannes P.T.M. van Leeuwen ◽  
Clemens A. van Blitterswijk ◽  
...  
Keyword(s):  

2006 ◽  
Vol 84 (4) ◽  
pp. 581-593 ◽  
Author(s):  
Anja Geitmann

Biomechanical studies aim at understanding the relationship between the mechanical properties of biological structures and their function. In cytomechanical investigations, this approach is brought down to the scale of cells and subcellular structures. In plant cells and the hyphae of fungi and water molds, interactions between turgor pressure, the cell wall, and the cytoskeleton are considered of primary importance. This review is an overview of how the mechanical properties of these individual features and their interactions have been measured and how the experimental data are used to produce theoretical mechanical models of cellular architecture and dynamics. Several models are discussed, and focusing on the example of tip-growing cells, various approaches to understanding the mechanical aspects of cellular morphogenesis are analyzed.


2006 ◽  
Vol 84 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Alicia G. Howe ◽  
Christopher R. McMaster

Phosphatidylcholine is the major phospholipid in eukaryotic cells and serves as both a permeability barrier as well as a modulator of a plethora of cellular and biological functions. This review touches on the importance of proper regulation of phosphatidylcholine metabolism on health, and discusses how yeast genetics has contributed to furthering our understanding of the precise molecular events regulated by alterations in phosphatidylcholine metabolism. Yeast studies have determined that the phosphatidylcholine and (or) phosphatidylinositol binding protein, Sec14, is a major regulator of phosphatidylcholine homeostasis. Sec14 itself regulates vesicular transport from the Golgi, and the interrelationship between phosphatidylcholine metabolism and membrane movement within the cell is described in detail. The recent convergence of the yeast genetic studies with that of mammalian cell biology in how cells maintain phosphatidylcholine homeostasis is highlighted.


2006 ◽  
Vol 84 (4) ◽  
pp. 444-439 ◽  
Author(s):  
Sui Huang ◽  
Lawrence I. Rothblum ◽  
Danyang Chen

Mammalian cells contain approximately 400 copies of the ribosomal RNA genes organized as tandem, head-to-tail repeats spread among 6–8 chromosomes. Only a subset of the genes is transcribed at any given time. Experimental evidence suggests that, in a specific cell type, only a fraction of the genes exists in a conformation that can be transcribed. An increasing body of study indicates that eukaryotic ribosomal RNA genes exist in either a heterochromatic nucleosomal state or in open euchromatic states in which they can be, or are, transcribed. This review will attempt to summarize our current understanding of the structure and organization of ribosomal chromatin.


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