Minisymposium 9: Legume Biology
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Abs #
M0904: Molecular mechanisms regulating environmental induction of flowering in Medicago truncatula
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Presenter: |
Samach, Alon Contact Presenter |
Authors | Paltiel, judith (A) Assouline, Yael (A) Rosen, Naomi (A) Penmesta, Varma (B) Cook, Douglas (B) Eshed, Ravit (A) Elbaz, Anat (A) Weiss, David (A) Kigel, Jaime (A) Ori, Naomi (A) Samach, Alon (A) | | Affiliations: |
(A): The Plant Sciences Faculty of Agriculture Hebrew University
(B): Department of Plant Pathology University of California Davis, CA 95616 USA.
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Seasonal environmental events such as gradual changes in daylength and temperature affect the timing of transition to flowering in many annual and perennial plants. Work in Arabidopsis and additional species suggest that some environmental signals converge on transcriptional regulation of common floral integrators such as FLOWERING LOCUS T (FT). Here we studied environmental induction of flowering in the model legume Medicago truncatula. Similarly to Arabidopsis, the transition to flowering in M. truncatula is hastened by long photoperiods and long periods of vernalization (40C for 2-3 weeks). Ecotypes collected in Israel retain a vernalization response even though winter temperatures in there are way above 40C. Here we show that this species is also highly responsive (flowers earlier) to mild ambient temperatures (120C) simulating winter conditions in its natural habitat. Similar ambient temperatures delay flowering time in Arabidopsis thaliana both by reducing FT transcript and FT activity. Physiological experiments and microscopic analysis allowed us to time the transition to flowering due to low temperatures, and to compare it to vernalization. We have made use of natural variation, and induced mutants to identify key genes involved in this process, and will provide here data suggesting that an FT gene in M.truncatula is transcriptionally regulated by all three environmental cues, and a mutation in this gene causes late flowering.
