AUTHOR=Wong Albert C. S. , Hecht Valérie F. G. , Picard Kelsey , Diwadkar Payal , Laurie Rebecca E. , Wen Jiangqi , Mysore Kirankumar , Macknight Richard C. , Weller James L. 

TITLE=Isolation and functional analysis of CONSTANS-LIKE genes suggests that a central role for CONSTANS in flowering time control is not evolutionarily conserved in Medicago truncatula

JOURNAL=Frontiers in Plant Science

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2014.00486

DOI=10.3389/fpls.2014.00486

ISSN=1664-462X

ABSTRACT=<p>The zinc finger transcription factor <italic>CONSTANS</italic> has a well-established central role in the mechanism for photoperiod sensing in Arabidopsis, integrating light and circadian clock signals to upregulate the florigen gene <italic>FT</italic> under long-day but not short-day conditions. Although <italic>CONSTANS</italic>-LIKE (<italic>COL</italic>) genes in other species have also been shown to regulate flowering time, it is not clear how widely this central role in photoperiod sensing is conserved. Legumes are a major plant group and various legume species show significant natural variation for photoperiod responsive flowering. Orthologs of several Arabidopsis genes have been shown to participate in photoperiodic flowering in legumes, but the possible function of <italic>COL</italic> genes as integrators of the photoperiod response has not yet been examined in detail. Here we characterize the <italic>COL</italic> family in the temperate long-day legume <italic>Medicago truncatula</italic>, using expression analyses, reverse genetics, transient activation assays and Arabidopsis transformation. Our results provide several lines of evidence suggesting that <italic>COL</italic> genes are unlikely to have a central role in the photoperiod response mechanism in this species.</p>