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Throughout their lifespan, plants continuously generate new growth, but only specific cells drive this process. Most plant cells remain incapable of producing flowers, as the genes responsible for flowering are deactivated. A recent study published in eLife reveals that the mechanism triggering flower formation lies within chromatin, the DNA-protein complex in a plant cell’s nucleus, and is regulated by the hormone auxin.
By examining Arabidopsis, commonly known as rockcress, scientists from the University of Pennsylvania, Howard Hughes Medical Institute, and the University of California, San Diego discovered that auxin plays a crucial role in loosening the tightly coiled DNA within chromatin. This action exposes the genes necessary for flowering, allowing them to be activated by a protein named MONOPTEROS. Without auxin-induced changes to chromatin’s structure, MONOPTEROS cannot access the genes required for flower development. Mutations in the proteins responsible for altering chromatin’s shape resulted in plants producing pin-like growths instead of flowers.
Plants with mutations in their chromatin remodeling genes develop pin-like structures rather than flowers (right).
"Auxin, a well-known hormone, plays a critical role in various processes such as embryo development, root and flower formation, vein patterning, and overall growth," says Doris Wagner, a biologist at Penn and co-author of the study, in a press statement. "Our findings reveal that auxin facilitates chromatin opening, enabling other proteins to access and activate diverse developmental pathways."
This mechanism may also influence leaf formation and other aspects of plant growth. The study opens possibilities for developing methods to enhance flowering in agricultural plants, potentially increasing crop yields.
