Arabidopsis ABF3 and ABF4 Transcription Factors Act with the NF-YC Complex to Regulate SOC1 Expression and Mediate Drought-Accelerated Flowering

Keumbi Hwang, Hendry Susila, Zeeshan Nasim, Ji Yul Jung, Ji Hoon Ahn

Research output: Contribution to journalArticlepeer-review

123 Citations (Scopus)

Abstract

The drought-escape response accelerates flowering in response to drought stress, allowing plants to adaptively shorten their life cycles. Abscisic acid (ABA) mediates plant responses to drought, but the role of ABA-responsive element (ABRE)-binding factors (ABFs) in the drought-escape response is poorly understood. Here, we show that Arabidopsis thaliana ABF3 and ABF4 regulate flowering in response to drought through transcriptional regulation of the floral integrator SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1). The abf3 abf4 mutant displayed ABA-insensitive late flowering under long-day conditions. Ectopic expression of ABF3 or ABF4 in the vasculature, but not in the shoot apex, induced early flowering, whereas expression of ABF3 fused with the SRDX transcriptional repressor domain delayed flowering. We identified SOC1 as a direct downstream target of ABF3/4, and found that SOC1 mRNA levels were lower in abf3 abf4 than in wild-type plants. Moreover, induction of SOC1 by ABA was hampered in abf3 abf4 mutants. ABF3 and ABF4 were enriched at the −1028- to −657-bp region of the SOC1 promoter, which does not contain canonical ABF-ABRE-binding motifs but has the NF-Y binding element. We found that ABF3 and ABF4 interact with nuclear factor Y subunit C (NF-YC) 3/4/9 in vitro and in planta, and induction of SOC1 by ABA was hampered in nf-yc3 yc4 yc9 mutants. Interestingly, the abf3 abf4, nf-yc3 yc4 yc9, and soc1 mutants displayed a reduced drought-escape response. Taken together, these results suggest that ABF3 and ABF4 act with NF-YCs to promote flowering by inducing SOC1 transcription under drought conditions. This mechanism might contribute to adaptation by enabling plants to complete their life cycles under drought stress. This study reports the molecular mechanism of the ABA-dependent drought-escape response pathway. We discovered that the ABF3 and ABF4 transcription factors bind to the promoter region of SOC1 and regulate its transcription, acting with the NF-Y complex. The regulatory network involving ABF3, ABF4, NF-YC, and SOC1 plays an important role in drought-accelerated flowering in Arabidopsis thaliana.

Original languageEnglish
Pages (from-to)489-505
Number of pages17
JournalMolecular Plant
Volume12
Issue number4
DOIs
Publication statusPublished - 2019 Apr 1

Bibliographical note

Funding Information:
This work was supported by a National Research Foundation of Korea grant funded by the Korean Government (NRF-2017R1A2B3009624 to J.H.A.) and Samsung Science and Technology Foundation under Project Number (SSTF-BA1602-12). We thank Prof. Kazuko Yamaguchi-Shinozaki (University of Tokyo, Japan), Prof. Nam-Chon Paek (Seoul National University, Korea), Prof. Xingliang Hou (South China Botanical Garden, China), and Prof. Soo Young Kim (Chonnam National University, Korea) for kindly providing research materials. We also thank Snježana Jurić for her technical comments. The authors declare no conflict of interest.

Funding Information:
This work was supported by a National Research Foundation of Korea grant funded by the Korean Government ( NRF-2017R1A2B3009624 to J.H.A.) and Samsung Science and Technology Foundation under Project Number (SSTF-BA1602-12).

Publisher Copyright:
© 2019 The Author

Keywords

  • ABF3
  • ABF4
  • NF-YC
  • SOC1
  • abscisic acid
  • drought escape

ASJC Scopus subject areas

  • Molecular Biology
  • Plant Science

Fingerprint

Dive into the research topics of 'Arabidopsis ABF3 and ABF4 Transcription Factors Act with the NF-YC Complex to Regulate SOC1 Expression and Mediate Drought-Accelerated Flowering'. Together they form a unique fingerprint.

Cite this