Microtubule configurations and nuclear DNA synthesis during initiation of suspensor-bearing embryos from Brassica napus cv. Topas microspores
Autor: | André A. M. van Lammeren, Ewa Dubas, Jan Custers, Maria Wędzony, Henk Kieft |
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Jazyk: | angličtina |
Předmět: |
DNA
Plant Plant embryogenesis Morphogenesis Apical cell Androgenesis Plant Science Biology heat-shock in-vitro Microtubules cultured microspores Microspore Microtubule rape embryogenesis division sporophytic development Cytoskeleton induction visualization Cells Cultured Genetics Cell Nucleus Original Paper Brassica napus Microtubular cytoskeleton Laboratorium voor Celbiologie Nuclear DNA synthesis General Medicine Cell cycle organization Cell biology PRI Bioscience Laboratory of Cell Biology Bromodeoxyuridine pollen Seeds Pollen Suspensor Agronomy and Crop Science Heat-Shock Response |
Zdroj: | Plant Cell Reports Plant Cell Reports 30 (2011) 11 Plant Cell Reports, 30(11), 2105-2116 |
ISSN: | 0721-7714 |
DOI: | 10.1007/s00299-011-1117-8 |
Popis: | In the new Brassica napus microspore culture system, wherein embryos with suspensors are formed, ab initio mimics zygotic embryogenesis. The system provides a powerful in vitro tool for studying the diverse developmental processes that take place during early stages of plant embryogenesis. Here, we studied in this new culture system both the temporal and spatial distribution of nuclear DNA synthesis places and the organization of the microtubular (MT) cytoskeleton, which were visualized with a refined whole mount immunolocalization technology and 3D confocal laser scanning microscopy. A ‘mild’ heat stress induced microspores to elongate, to rearrange their MT cytoskeleton and to re-enter the cell cycle and perform a predictable sequence of divisions. These events led to the formation of a filamentous suspensor-like structure, of which the distal tip cell gave rise to the embryo proper. Cells of the developing pro-embryo characterized endoplasmic (EMTs) and cortical microtubules (CMTs) in various configurations in the successive stages of the cell cycle. However, the most prominent changes in MT configurations and nuclear DNA replication concerned the first sporophytic division occurring within microspores and the apical cell of the pro-embryo. Microspore embryogenesis was preceded by pre-prophase band formation and DNA synthesis. The apical cell of the pro-embryo exhibited a random organization of CMTs and, in relation to this, isotropic expansion occurred, mimicking the development of the apical cell of the zygotic situation. Moreover, the apical cell entered the S phase shortly before it divided transversally at the stage that the suspensor was 3–8 celled. |
Databáze: | OpenAIRE |
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