Biologists at the University of California, San Diego have discovered how to genetically convert leaves into petals, an achievement that may be the botanical equivalent of the medieval alchemists' dream of transmuting iron into gold.
In a cover article in the February issue of the scientific journal Current Biology, the UCSD scientists show that a new class of floral genes that they recently discovered, together with three other genes responsible for flower development, are sufficient to convert leaves into petals.
"This is a very exciting discovery," notes Martin F. Yanofsky, a professor of biology at UCSD who conducted the study with UCSD biologist Soraya Pelaz in collaboration with Rosalinda Tapia-Lopez and Elena R. Alvarez-Buylla of the National Autonomous University of Mexico in Mexico City. "We've known for a decade how to convert the flower organs into leaves, but we haven't been able to convert leaves into flower organs. We knew we were missing a piece of the puzzle and now we know exactly what we were missing."
The team's discovery has important commercial as well as scientific implications. "It means that we should be able to convert leaves of essentially any plant into petals, which could certainly make for some very interesting looking plants," adds Yanofsky. "Imagine, for example, a long-stemmed rose in which the many leaves along the stem are each converted into colorful petals."
Normal flowers consist of a series of four rings or "whorls." The outermost whorl is made up of sepals, the green leaf-like organ that normally surrounds the flower bud before it opens. Inside the sepals is a ring of petals, then a ring of stamens, the male reproductive structures, and at the center are the carpels (often referred to as the pistils), the female reproductive structures.