Cellularisation in the endosperm of Arabidopsis thaliana is coupled to mitosis and shares multiple components with cytokinesis.
Distinct forms of cytokinesis characterise specific phases of development in plants. In Arabidopsis, as in many other species, the endosperm that nurtures the embryo in the seed initially develops as a syncytium. This syncytial phase ends with simultaneous partitioning of the multinucleate cytoplasm into individual cells, a process referred to as cellularisation. Our in vivo observations show that, as in cytokinesis, cellularisation of the Arabidopsis endosperm is coupled to nuclear division. A genetic analysis reveals that most Arabidopsis mutations affecting cytokinesis in the embryo also impair endosperm cellularisation. These results imply that cellularisation and cytokinesis share multiple components of the same basic machinery. We further report the identification of mutations in a novel gene, SPATZLE, that specifically interfere with cellularisation of the endosperm, but not with cytokinesis in the embryo. The analysis of this mutant might identify a specific checkpoint for the onset of cellularisation.
Sørensen
Mikael Blom
MB
Laboratoire de Reproduction et Développement des Plantes, UMR 5667, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, F-69364 Lyon, Cedex 07, France.
Mayer
Ulrike
U
Lukowitz
Wolfgang
W
Robert
Hélène
H
Chambrier
Pierre
P
Jürgens
Gerd
G
Somerville
Chris
C
Lepiniec
Loic
L
Berger
Frédéric
F
D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division; D002467:Cell Nucleus / Q000502:physiology; D002473:Cell Wall; D002874:Chromosome Mapping; D006720:Homozygote; D018613:Microscopy, Confocal; D008938:Mitosis; D009154:Mutation; D010641:Phenotype; D013997:Time Factors
D029681:Arabidopsis Proteins