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Arabidopsis CDKA;1, a cdc2 homologue, controls proliferation of generative cells in male gametogenesis

Arabidopsis CDKA;1, a cdc2 homologue, controls proliferation of generative cells in male... The protein kinase cdc2 is conserved throughout eukaryotes and acts as a key regulator of the cell cycle. In plants, A‐type cyclin‐dependent kinase (CDKA), a homologue of cdc2, has a role throughout the cell cycle. Here we show that a loss‐of‐function mutation in CDKA;1, encoding the only Arabidopsis CDKA, results in lethality of the male gametophyte. Heterozygous plants produced mature siliques containing about 50% aborted seeds, and segregation distortion was observed in paternal inheritance. Microspores normally undergo an asymmetric cell division, pollen mitosis I (PMI), to produce bicellular pollen grains. The larger vegetative cell does not divide, but the smaller generative cell undergoes mitosis, PMII, to form the two sperm cells, thereby generating tricellular pollen grains. The cdka‐1 mutant, however, produces mature bicellular pollen grains, consisting of a single sperm‐like cell and a vegetative cell, due to failure of PMII. The mutant sperm‐like cell is fertile, and preferentially fuses with the egg cell to initiate embryogenesis. As the central cell nucleus remains unfertilized, however, double fertilization does not occur. In heterozygous plants, the embryo is arrested at the globular stage, most likely because of loss of endosperm development, whereas it is arrested at the one‐ or two‐cell stage in presumptive homozygous plants. Thus, CDKA;1 is essential for cell division of the generative cell in male gametogenesis. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Plant Journal Wiley

Arabidopsis CDKA;1, a cdc2 homologue, controls proliferation of generative cells in male gametogenesis

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References (96)

Publisher
Wiley
Copyright
Copyright © 2006 Wiley Subscription Services, Inc., A Wiley Company
ISSN
0960-7412
eISSN
1365-313X
DOI
10.1111/j.1365-313X.2005.02643.x
pmid
16460514
Publisher site
See Article on Publisher Site

Abstract

The protein kinase cdc2 is conserved throughout eukaryotes and acts as a key regulator of the cell cycle. In plants, A‐type cyclin‐dependent kinase (CDKA), a homologue of cdc2, has a role throughout the cell cycle. Here we show that a loss‐of‐function mutation in CDKA;1, encoding the only Arabidopsis CDKA, results in lethality of the male gametophyte. Heterozygous plants produced mature siliques containing about 50% aborted seeds, and segregation distortion was observed in paternal inheritance. Microspores normally undergo an asymmetric cell division, pollen mitosis I (PMI), to produce bicellular pollen grains. The larger vegetative cell does not divide, but the smaller generative cell undergoes mitosis, PMII, to form the two sperm cells, thereby generating tricellular pollen grains. The cdka‐1 mutant, however, produces mature bicellular pollen grains, consisting of a single sperm‐like cell and a vegetative cell, due to failure of PMII. The mutant sperm‐like cell is fertile, and preferentially fuses with the egg cell to initiate embryogenesis. As the central cell nucleus remains unfertilized, however, double fertilization does not occur. In heterozygous plants, the embryo is arrested at the globular stage, most likely because of loss of endosperm development, whereas it is arrested at the one‐ or two‐cell stage in presumptive homozygous plants. Thus, CDKA;1 is essential for cell division of the generative cell in male gametogenesis.

Journal

The Plant Journal – Wiley

Published: Mar 1, 2006

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