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Analysis of conifer FLOWERING LOCUS T / TERMINAL FLOWER1 ‐like genes provides evidence for dramatic biochemical evolution in the angiosperm FT lineage
Author(s) -
Klintenäs Maria,
Pin Pierre A.,
Benlloch Reyes,
Ingvarsson Pär K.,
Nilsson Ove
Publication year - 2012
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2012.04332.x
Subject(s) - gymnosperm , biology , functional divergence , gene , lineage (genetic) , locus (genetics) , flowering plant , phylogenetics , evolutionary biology , genetics , gene duplication , gene family , botany , subfunctionalization , genome
Summary In flowering plants, homologs of the A rabidopsis phosphatidylethanolamine‐binding protein ( PEBP ) FLOWERING LOCUS T ( FT ) are key components in controlling flowering time. We show here that, although FT homologs are found in all angiosperms with completed genome sequences, there is no evidence to date that FT ‐ like genes exist in other groups of plants. Through phylogeny reconstructions and heterologous expression, we examined the biochemical function of the P icea (spruces) and P inus (pines) PEBP families – two gymnosperm taxa phylogenetically distant from the angiosperms. We have defined a lineage of gymnosperm PEBP genes, termed the FT/TERMINAL FLOWER1 ( TFL1 )‐like genes, that share sequence characteristics with both the angiosperm FT ‐ and TFL1 ‐like clades. When expressed in A rabidopsis, FT/TFL1 ‐like genes repressed flowering, indicating that the proteins are biochemically more similar to the angiosperm TFL1 ‐like proteins than to the FT ‐like proteins. This suggests that the regulation of the vegetative‐to‐reproductive switch might differ in gymnosperms compared with angiosperms. Molecular evolution studies suggest that plasticity at exon 4 contributes to the divergence of FT ‐like function in floral promotion. In addition, the presence of FT ‐like genes in basal angiosperms indicates that the FT ‐like function emerged at an early stage during the evolution of flowering plants as a means to regulate flowering time.