In rice, an unprecedented mechanism regulates the flowering process

An unprecedented mechanism for flowering development has been discovered in rice that runs counter to more than a century of studies and research: it is regulated by a molecular signal (florigen) that is not produced in the leaves, as was always thought hitherto, but directly in the bud. Closing them causes an increase in flowers and seeds, thus increasing the yield of the plant. A study proves it published In the journal Nature Plants by an international group of experts coordinated by Fabio Fornara, Professor at Milan State University.

The study is part of the work devoted to photosynthesis in plants and the mechanisms that enable them to understand what period of the year they are in order to begin flowering (and thus reproduction) at the most advantageous moment for plant reproduction. classify. The trigger is usually given by small globular proteins, phloregens, that are produced in the leaves and that move along the veins to get to the shoot.

Surprisingly, however, the new study on rice by the state researchers demonstrates “the presence of florigen produced directly in the plant bud, the region of the plant that contains stem cells and is responsible for flower formation,” explains Fornara. This new florigen “contributes only insignificantly to the determination of the time of flowering: its main function is to determine the number of branches of flowering”.

Using mutants resulting from chemical mutagenesis or gene-editing techniques, the researchers showed that deleting the gene from a plant causes a significant increase in the number of flowering branches, which results in an increase in the number of flowers. “This change in plant development plan is of particular importance from the point of view of biotechnology and genetic improvement, as more flowers can lead to a greater number of seeds and thus to higher yields,” Fornara adds. Moreover, the mechanism discovered in rice is conserved in other grains where it can be exploited to improve production.”