An embryo-derived peptide signal directs endosperm polarity in Arabidopsis
- Audrey Creff
- Jack Rhodes
- Camille Salaün
- Julien Larive
- Vincent Bayle
- Maialen Garmendia-Calvo
- Emma Turley
- Tatsuya Nobori
- Duarte D. Figueiredo
- Benoit Landrein
- Cyril Zipfel
- Gwyneth Ingram
2026-09-03
Angiosperm seed formation requires the coordinated development of the products of double fertilization—the embryo and the endosperm. The endosperm mediates efficient nutrient transfer from surrounding maternal tissues to the developing embryo. This function requires a polarized tissue organization, which manifests as early polar gene expression and polar cellularization dynamics. We show that the receptor kinase HAIKU2 (IKU2) acts in coordination with the transcription factor WRKY10/MINISEED3 (MINI3) to ensure robust endosperm polarity establishment through the activity of the homeodomain transcription factors WUSCHEL-RELATED HOMEOBOX 8 (WOX8) and WOX9. This process depends on egg cell fertilization and is mediated through the peptide PATHOGEN-INDUCED PEPTIDE–LIKE 7 (PIPL7), which acts as a potential IKU2 ligand. Our results reveal how a molecular paracrine dialog between the embryo and endosperm ensures optimal seed developmental coordination.