A Floral Mystery Resolved

The development of plant organs, their position, shapes and boundaries, are controlled by genes that can sustain their activation over long periods of time. These genes or genetic switches have long puzzled plant molecular biologists. In the model plant Arabidopsis thaliana, a particular type of these genes-the DEF and GLO-like floral genes-controls the development of stamens and petals. These genes are activated by a complex of their protein products and share common transcription factors. This makes their activity dependent on each other. The reason for their total functional interdependence has long remained a mystery.

Using computational modeling, a group of researchers from the University of Jena in Germany has provided an explanation to this floral mystery. A single gene alone could in principle provide the switching functionality in these plants' organs. But the researchers found that the pairing of DEF and GLO-like genes “reduces the susceptibility of the genetic switch to failure caused by interference.” This finding strongly supports the view that the appearance of this regulatory mechanism during angiosperm development leads to the suppression of phenotypic variation caused by the genotype or the environment.

The paper authored by Peter Dittrich and colleagues is available at http://dx.doi.org/10.1371/journal.pcbi.1000264