Mechanical stress mediated by both endosperm softening and embryo growth underlies endosperm elimination in Arabidopsis seeds.
Seed development in angiosperms demands the tightly coordinated development of three genetically distinct structures. The embryo is surrounded by the endosperm, which is in turn enclosed within the maternally derived seed coat. In Arabidopsis, final seed size is determined by early expansion of the coenocytic endosperm, which then cellularises and subsequently undergoes developmental programmed cell death, breaking down as the embryo grows. Endosperm breakdown requires the endosperm-specific basic helix-loop-helix transcription factor ZHOUPI. However, to date, the mechanism underlying the Arabidopsis endosperm breakdown process has not been elucidated. Here, we provide evidence that ZHOUPI does not induce the developmental programmed cell death of the endosperm directly. Instead ZHOUPI indirectly triggers cell death by regulating the expression of cell wall-modifying enzymes, thus altering the physical properties of the endosperm to condition a mechanical environment permitting the compression of the cellularised endosperm by the developing embryo.
Laboratoire Reproduction et Développement des Plantes, University of Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon F-69342, France.
Chloé
C
Fourquin
Laboratoire Reproduction et Développement des Plantes, University of Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon F-69342, France.
Léna
L
Beauzamy
Laboratoire Reproduction et Développement des Plantes, University of Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon F-69342, France.
Sophy
S
Chamot
Laboratoire Reproduction et Développement des Plantes, University of Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon F-69342, France.
Audrey
A
Creff
Institute of Molecular Plant Sciences, University of Edinburgh, Institute of Molecular Plant Sciences, Daniel Rutherford Building, Edinburgh EH9 3BF, UK.
Justin
J
Goodrich
Laboratoire Reproduction et Développement des Plantes, University of Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon F-69342, France.
Arezki
A
Boudaoud
Laboratoire Reproduction et Développement des Plantes, University of Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, Lyon F-69342, France Gwyneth.Ingram@ens-lyon.fr.
Gwyneth
0000-0002-1425-9545
G
Ingram
D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D016923:Cell Death / Q000502:physiology; D056625:Endosperm / Q000378:metabolism*; D012639:Seeds / Q000378:metabolism*; D013314:Stress, Mechanical
D029681:Arabidopsis Proteins
Biophysics; Cell death; Cell wall; Embryo; Endosperm; Seed