Year-end Sale % OFF 
Abstract
FLOWERING LOCUS T (FT) genes encode proteins that function as the mobile floral signal, florigen. In this study, we characterized five FT-like genes from the model legume, Medicago (Medicago truncatula). The different FT genes showed distinct patterns of expression and responses to environmental cues. Three of the FT genes (MtFTa1, MtFTb1, and MtFTc) were able to complement the Arabidopsis (Arabidopsis thaliana) ft-1 mutant, suggesting that they are capable of functioning as florigen. MtFTa1 is the only one of the FT genes that is up-regulated by both long days (LDs) and vernalization, conditions that promote Medicago flowering, and transgenic Medicago plants overexpressing the MtFTa1 gene flowered very rapidly. The key role MtFTa1 plays in regulating flowering was demonstrated by the identification of fta1 mutants that flowered significantly later in all conditions examined. fta1 mutants do not respond to vernalization but are still responsive to LDs, indicating that the induction of flowering by prolonged cold acts solely through MtFTa1, whereas photoperiodic induction of flowering involves other genes, possibly MtFTb1, which is only expressed in leaves under LD conditions and therefore might contribute to the photoperiodic regulation of flowering. The role of the MtFTc gene is unclear, as the ftc mutants did not have any obvious flowering-time or other phenotypes. Overall, this work reveals the diversity of the regulation and function of the Medicago FT family.
Highlights
FLOWERING LOCUS T (FT) genes encode proteins that function as the mobile floral signal, florigen
To precisely control the timing of flowering, plants have evolved mechanisms to integrate seasonally predictable environmental cues and developmental cues. To allow this diversity of floral cues to influence when flowering occurs in Arabidopsis (Arabidopsis thaliana), multiple pathways converge on a small number of genes, the floral integrator genes, including the floral promoters FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF; Amasino, 2010)
The FT-like genes have a similar genomic structure to the FT genes from other species, with four exons and three introns (Supplemental Fig. S1A), and reverse transcription (RT)-PCR confirmed that all five FT-like genes are expressed
Summary
FLOWERING LOCUS T (FT) genes encode proteins that function as the mobile floral signal, florigen. To precisely control the timing of flowering, plants have evolved mechanisms to integrate seasonally predictable environmental cues (such as changes in photoperiod and prolonged periods of cold temperatures) and developmental cues (such as maturity; Amasino, 2010) To allow this diversity of floral cues to influence when flowering occurs in Arabidopsis (Arabidopsis thaliana), multiple pathways converge on a small number of genes, the floral integrator genes, including the floral promoters FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF; Amasino, 2010). Hecht et al (2011) have shown that the pea FTa1 gene corresponds to the GIGAS locus, which encodes a mobile floral signal that is essential for flowering under LD and promotes flowering under SD but is not required for the photoperiodic response They provide evidence for a second mobile floral signal that correlates with the expression of another FT-like gene, FTb2. A recent paper implicates two FT-like genes in the regulation of flowering of the SD legume soybean (Glycine max; Kong et al, 2010)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
