SHB1 plays dual roles in photoperiodic and autonomous flowering

Yun Zhou, Min Ni

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Flowering was initiated by the integration of environmental signals such as day-length with the internal development status in Arabidopsis, a facultative long-day plant. The photoperiodic flowering involves two key components, CONSTANS and FT, whereas the autonomous flowering is operated through a central quantitative floral repressor, FLC, and several other genes that act upstream of FLC. SOC1 acts downstream to integrate the flowering signals from the two pathways. Here, we report that SHB1 plays dual roles in both photoperiodic and autonomous flowering. shb1-D, a gain-of-function mutant, flowered early and shb1, a loss-of-function allele, flowered late under both long days and short days. The shb1-D mutation activated the expression of CO, FT, and SOC1 under both long and short days, and however, the co-2 mutation attenuated the shb1-D activated expression of FT and SOC1 only under long days but not short days. The shb1-D or shb1 mutations also reduced and increased, respectively, the expression of FLC under both long and short days. Transgenic remedy of FLC to wide-type level in shb1-D background also reverted shb1-D flowering and FT or SOC1 expression to wild type mostly under short days. Furthermore, the shb1-D suppression on FLC expression is likely operated through LD as ld-3 blocked this suppression and SHB1 appears to act upstream of LD. In summary, SHB1 represents signaling steps that regulate CO expression in leaves and LD or FLC expression in either leaves or shoot apical meristem, contributing to a threshold expression of SOC1 in shoot apical meristem for floral initiation.

Original languageEnglish (US)
Pages (from-to)50-57
Number of pages8
JournalDevelopmental Biology
Volume331
Issue number1
DOIs
StatePublished - Jul 1 2009

Bibliographical note

Funding Information:
We thank the Arabidopsis Biological Resource Center (ABRC, Columbus, OH, USA) for Arabidopsis T-DNA insertion collections and mutant seeds. We thank Dr. Scott D. Michaels for providing flc-3 mutant. This work was supported by a grant from the National Research Initiative of the USDA Cooperative State Research, Education and Extension Service (2004-35304-14939 to M.N.).

Keywords

  • Arabidopsis
  • Autonomous flowering
  • CONSTANS
  • FLOWERING LOCUS C
  • LUMINIDEPENDENS
  • Photoperiodic flowering

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