Monday, April 13, 2009

Florigen - found and not found

From Science magazine's list of the 'Breakthrough's of the year' in 2005:

In August three groups of plant molecular biologists finally pinned down the identity of florigen, a signal that initiates the seasonal development of flowers. The signal is the messenger RNA of a gene called FT. When days get long enough, this RNA moves from leaves to the growth tip, where the FT protein interacts with a growth tip-specific transcription factor, FD.

However if you click on the original article then you may notice the sentence 'This article has been retracted.'

After the first author (T.H.) left the UmeƄ Plant Science Centre for another position, analysis of his original data revealed several anomalies. It is apparent from these files that data from the real-time RT-PCR were analyzed incorrectly. Certain data points were removed, while other data points were given increased weight in the statistical analysis. When all the primary real-time RT-PCR data are subjected to correct statistical analysis, most of the reported significant differences between time points disappear. Because of this, we are retracting the paper in its entirety.

In new experiments, we have reproduced the floral induction caused by a heat-shock induction of FT in a single leaf, but we have failed to detect movement of the transgenic FT mRNA from leaf to shoot apex. We therefore retract the conclusion that FT mRNA is part of the floral inductive signal moving from leaf to shoot apex.

Curious. After 70 years of elusivity (is that a word?) Florigen is not ready to give in yet.

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