Details

Autor(en) / Beteiligte

• Sánchez-Montesino, Rocío
• Bouza-Morcillo, Laura
• Marquez, Julietta
• Ghita, Melania
• Duran-Nebreda, Salva
• Gómez, Luis
• Holdsworth, Michael J.
• Bassel, George
• Oñate-Sánchez, Luis

Titel

A Regulatory Module Controlling GA-Mediated Endosperm Cell Expansion Is Critical for Seed Germination in Arabidopsis

Ist Teil von

• Molecular plant, 2019-01, Vol.12 (1), p.71-85

Ort / Verlag

England: Elsevier Inc

Erscheinungsjahr

2019

Quelle

MEDLINE

Beschreibungen/Notizen

• A key component of seed germination is the interplay of mechanical forces governing embryo growth and the surrounding restraining endosperm tissue. Endosperm cell separation is therefore thought to play a critical role in the control of this developmental transition. Here we demonstrate that in Arabidopsis thaliana seeds, endosperm cell expansion is a key component of germination. Endosperm cells expand to accommodate embryo growth prior to germination. We show that this is an actively regulated process supported by spatiotemporal control of the cell expansion gene EXPANSIN 2 (EXPA2). The NAC transcription factors NAC25 and NAC1L were identified as upstream regulators of EXPA2 expression, gibberellin-mediated endosperm expansion, and seed germination. The DELLA protein RGL2 repressed activation of the EXPA2 promoter by NAC25/NAC1L. Taken together, our findings uncover a key role of the GA/DELLA-NAC25/NAC1L-EXPA2 network in regulating endosperm cell expansion to control the seed-to-seedling transition. This study demonstrates that endosperm cell expansion is crucial for germination and that two NAC transcription factors play pivotal roles in this process. NAC25 and NAC1L act downstream of GAs and the RGL2 DELLA protein to upregulate cell-wall remodeling enzyme gene expression.