CRYPTIC PRECOCIOUS/MED12 is a novel flowering regulator with multiple target steps in Arabidopsis

Plant Cell Physiol. 2012 Feb;53(2):287-303. doi: 10.1093/pcp/pcs002. Epub 2012 Jan 13.

Abstract

The proper timing of flowering is of crucial importance for reproductive success of plants. Regulation of flowering is orchestrated by inputs from both environmental and endogenous signals such as daylength, light quality, temperature and hormones, and key flowering regulators construct several parallel and interactive genetic pathways. This integrative regulatory network has been proposed to create robustness as well as plasticity of the regulation. Although knowledge of key genes and their regulation has been accumulated, there still remains much to learn about how they are organized into an integrative regulatory network. Here, we have analyzed the CRYPTIC PRECOCIOUS (CRP) gene for the Arabidopsis counterpart of the MED12 subunit of the Mediator. A novel dominant mutant, crp-1D, which causes up-regulation of SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), FRUITFULL (FUL) and APETALA1 (AP1) expression in a FLOWERING LOCUS T (FT)-dependent manner, was identified in an enhancer screen of the early-flowering phenotype of 35S::FT. Genetic and molecular analysis of both crp-1D and crp loss-of-function alleles showed that MED12/CRP is required not only for proper regulation of SOC1, FUL and AP1, but also for up-regulation of FT, TWIN SISTER OF FT (TSF) and FD, and down-regulation of FLOWERING LOCUS C (FLC). These observations suggest that MED12/CRP is a novel flowering regulator with multiple regulatory target steps both upstream and downstream of the key flowering regulators including FT florigen. Our work, taken together with recent studies of other Mediator subunit genes, supports an emerging view that the Mediator plays multiple roles in the regulation of flowering.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis / physiology
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Flowers / physiology*
  • Gene Expression Regulation, Developmental
  • Gene Expression Regulation, Plant
  • MADS Domain Proteins / metabolism
  • Mutation
  • Phosphatidylethanolamine Binding Protein / metabolism
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism
  • Plants, Genetically Modified / physiology
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*

Substances

  • Arabidopsis Proteins
  • CENTRAL CITY protein, Arabidopsis
  • FLF protein, Arabidopsis
  • FT protein, Arabidopsis
  • GRAND CENTRAL protein, Arabidopsis
  • MADS Domain Proteins
  • Phosphatidylethanolamine Binding Protein
  • Repressor Proteins
  • TSF protein, Arabidopsis