The role of FLC as a key regulator of multiple developmental transitions

GABRIELA A AUGE; LOGAN K BLAIR; KATHLEEN DONOHUE

Portland, Oregon

Conferencia; Plant Biology 2014; 2014

American Society of Plant Biology

How plants respond to seasonal environments to regulate development across their life cycle depends on the integration of environmental information at multiple life stages. The gene Flowering locus C (FLC) is a central regulator of flowering time in Arabidopsis thaliana, and it was also reported to be a promoter of seed germination; high FLC expression in siliques was associated with greater germination proportions. How closely associated are these two FLC-mediated responses? Specifically, does FLC-mediated regulation of flowering have carry-over effectson FLC-mediated germination? To address this question, plants of 22 ecotypes, that vary both in the level of FLC expression in rosettes and in the propensity to germinate, were either vernalized or not vernalized, and allowed to mature seeds under controlled conditions. Seeds were harvested, after-ripened, and incubated under a 12h light/12h dark cycle at 10 or 22°C, and germination proportions were recorded. As expected, vernalization accelerated flowering the most for ecotypes with strong FLC alleles. While germination was highly variable among ecotypes, vernalization did not significantly influence the final proportion of seeds that germinated in most ecotypes. In some of them, however, vernalization tended to increase germination, contrary to expectation if FLC-mediated vernalization has carry-over effects on germination. To further investigate the association between rosette vernalization and germination, we tested whether other genes in the vernalization pathway influenced germination. We found evidence that FRIGIDA, VIPs, and VIN3 do influence germination. Combined, the results suggest that FLC-mediated vernalization appears to be uncoupled from FLC-mediated germination, but that other genes in the vernalization pathway can mediate vernalization effects on germination independently of FLC.