Plant Molecular Biology

, Volume 56, Issue 2, pp 159-169

First online:

Photoperiodic regulation of flowering in perennial ryegrass involving a CONSTANS-like homolog

  • Jérome MartinAffiliated withPlant Research Department, Risø National LaboratoryDLF-Trifolium Ldt, Research DivisionBiogemma, Gene Function and Maize Traits Group
  • , Morten StorgaardAffiliated withPlant Research Department, Risø National Laboratory
  • , Claus H. AndersenAffiliated withDLF-Trifolium Ldt, Research Division
  • , Klaus K. NielsenAffiliated withDLF-Trifolium Ldt, Research Division

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Photoperiod and vernalization are the two key environmental factors of the floral induction of perennial ryegrass (Lolium perenneL.). Transition from vegetative to reproductive growth will only occur after an extended vernalization period, followed by an increase in day length and temperature. Here we report on the isolation and characterization of a L. perennegene (LpCO) that is homologous to CONSTANS, and which is tightly coupled to the floral inductive long day signal. Like other monocot CO-like proteins, the LpCO contains a zinc finger domain with a non-conserved B-Box2. Although the B-Box2 has been demonstrated to be essential for the function of the ArabidopsisCO (AtCO), LpCO is able to complement the Arabidopsis co-2 mutant, and ectopic expression in Arabidopsis wild type leads to early flowering. The LpCO transcript exhibits diurnal oscillations and is expressed at higher levels during long days.

Arabidopsis CONSTANS flowering Lolium perenne photoperiod