TY - JOUR
T1 - A regulatory module controlling GA-mediated endosperm cell expansion is critical for seed germination in Arabidopsis
AU - Sánchez-Montesino, Rocío
AU - Bouza-Morcillo, Laura
AU - Marquez, Julietta
AU - Ghita, Melania
AU - Duran-Nebreda, Salva
AU - Gómez, Luis
AU - Holdsworth, Michael J.
AU - Bassel, George
AU - Oñate-Sánchez, Luis
PY - 2019/1/7
Y1 - 2019/1/7
N2 - 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.
AB - 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.
KW - cell expansion
KW - cell-wall remodeling enzymes
KW - endosperm
KW - expansin
KW - NAC transcription factors
KW - seed germination
UR - http://www.scopus.com/inward/record.url?scp=85058370610&partnerID=8YFLogxK
U2 - 10.1016/j.molp.2018.10.009
DO - 10.1016/j.molp.2018.10.009
M3 - Article
SN - 1674-2052
VL - 12
SP - 71
EP - 85
JO - Molecular Plant
JF - Molecular Plant
IS - 1
ER -