The FLOWERING LOCUS T LIKE 2-1 gene of Chenopodium triggers precocious
flowering in Arabidopsis seedlings
Abstract
The FLOWERING LOCUS T ( FT) gene is the essential
integrator of flowering regulatory pathways in angiosperms. The paralogs
of the FT gene may perform antagonistic functions, as exemplified
by BvFT1, that suppresses flowering in Beta vulgaris,
unlike the paralogous activator BvFT2. The roles of FT
genes in other amaranths were less investigated. Here, we transformed
Arabidopsis thaliana with the FLOWERING LOCUS T like (
FTL) genes of Chenopodium ficifolium and found,
that both CfFTL1 and CfFTL2-1 accelerated flowering,
despite having been the homologs of the Beta vulgaris floral
promoter and suppressor, respectively. The floral promotive effect of
CfFTL2-1 was so strong that it caused lethality when
overexpressed under the 35S promoter. CfFTL2-1 placed in
inducible cassette accelerated flowering after the induction with
methoxyphenozide. The spontaneous induction of CfFTL2-1 led to
precocious flowering in some primary transformants even without chemical
induction. The CqFT2-1 homolog from Chenopodium quinoa had
the same impact on viability and flowering as CfFTL2-1, when
transferred to A. thaliana. After the FTL gene duplication
in Amaranthaceae, the FTL1 copy maintained the role of floral
activator. The second copy FTL2 underwent subsequent duplication
and functional diversification, which enabled to control the onset of
flowering in amaranths to adapt to variable environments.