The NF-YC-RGL2 module integrates GA and ABA signalling to regulate seed germination in Arabidopsis.

Xu Liu,Yang Tang,Yuge Li,Ling Li,Pengwei Hu,Mingkun Huang,Xingliang Hou

doi:10.1038/ncomms12768

Abstract

The antagonistic crosstalk between gibberellic acid (GA) and abscisic acid (ABA) plays a pivotal role in the modulation of seed germination. However, the molecular mechanism of such phytohormone interaction remains largely elusive. Here we show that three Arabidopsis NUCLEAR FACTOR-Y C (NF-YC) homologues NF-YC3, NF-YC4 and NF-YC9 redundantly modulate GA- and ABA-mediated seed germination. These NF-YCs interact with the DELLA protein RGL2, a key repressor of GA signalling. The NF-YC–RGL2 module targets ABI5, a gene encoding a core component of ABA signalling, via specific CCAAT elements and collectively regulates a set of GA- and ABA-responsive genes, thus controlling germination. These results suggest that the NF-YC–RGL2–ABI5 module integrates GA and ABA signalling pathways during seed germination.

Highlights

The antagonistic crosstalk between gibberellic acid (GA) and abscisic acid (ABA) plays a pivotal role in the modulation of seed germination
Nf-yc[3] nf-yc[4] nf-yc[9], the combinatorial null mutant of the closest homologues NF-YC3, NF-YC4 and NF-YC9 in Arabidopsis NUCLEAR FACTOR-Y C (NF-YC) subfamily, similar to the key GA-related germination repressor mutant rgl[2], showed a strong resistance to PAC, but it has no difference in germination rate with the wild-type under mock treatment (Fig. 1a,b)
There was no significant difference in germination performance between the single or double mutants of NF-YC3/4/9 and the wild type (Supplementary Fig. 1a,b)

Summary

Introduction

The antagonistic crosstalk between gibberellic acid (GA) and abscisic acid (ABA) plays a pivotal role in the modulation of seed germination. We show that three Arabidopsis NUCLEAR FACTOR-Y C (NF-YC) homologues NF-YC3, NF-YC4 and NF-YC9 redundantly modulate GA- and ABA-mediated seed germination These NF-YCs interact with the DELLA protein RGL2, a key repressor of GA signalling. The NF-YC–RGL2 module targets ABI5, a gene encoding a core component of ABA signalling, via specific CCAAT elements and collectively regulates a set of GA- and ABA-responsive genes, controlling germination. These results suggest that the NF-YC–RGL2–ABI5 module integrates GA and ABA signalling pathways during seed germination. Studies have suggested a significant crosstalk of GA and ABA signalling during seed germination, the detailed mechanism of antagonism between these two phytohormones by which the plants precisely modulate germination remains elusive. The diverse roles of NF-YCs, together with those of another two NF-Y subunits NF-YA and NF-YB, imply the widely flexible formation of NF-Y complex that are spatially and temporally regulated by various developmental and growth conditions[27,37]

Methods

Results

Conclusion