Molecular Basis of Natural Variation in Photoperiodic Flowering Responses

Dev Cell. 2019 Jul 1;50(1):90-101.e3. doi: 10.1016/j.devcel.2019.05.018. Epub 2019 Jun 6.

Abstract

Plants exhibit different flowering behaviors in response to variable photoperiods across a wide geographical range. Here, we identify MYC3, a bHLH transcription factor, and its cis-element form the long-sought regulatory module responsible for cis-regulatory changes at the florigen gene FLOWERING LOCUS T (FT) that mediate natural variation in photoperiodic flowering responses in Arabidopsis. MYC3 is stabilized by DELLAs in the gibberellin pathway to suppress FT through binding the ACGGAT motif and antagonizing CONSTANS (CO) activation. Changing photoperiods modulate the relative abundance of MYC3 and CO, thus determining either of them as the predominant regulator for FT expression under different day lengths. Cis-regulatory changes in the MYC3 binding site at FT are associated with natural variation in day-length requirement for flowering in Arabidopsis accessions. Our findings reveal that environmental and developmental signals converge at MYC3 suppression of FT, an elementary event underlying natural variation in photoperiodic flowering responses.

Keywords: Arabidopsis; FT; MYC3; cis-regulatory changes; florigen; flowering time; gibberellin; natural variation; photoperiod; transcription factor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Databases, Genetic
  • Flowers / genetics
  • Flowers / growth & development*
  • Flowers / metabolism
  • Gene Expression Regulation, Plant*
  • Photoperiod*
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / growth & development*
  • Plants, Genetically Modified / metabolism
  • Signal Transduction
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism

Substances

  • Arabidopsis Proteins
  • CONSTANS protein, Arabidopsis
  • DNA-Binding Proteins
  • FT protein, Arabidopsis
  • GAI protein, Arabidopsis
  • MYC3 protein, Arabidopsis
  • Trans-Activators
  • Transcription Factors