Biology 103
2001 First Web Report
On Serendip

How would the plant world evolve if scientists were able to transform plant leaves into petals? How would the appearance of plants be altered? Would there be any benefits? For more than two centuries, biologists have acknowledged the relationship between the sepal, petal, stamen, and carpel organs that comprise a typical flowering plant and the leaves of the plant. A widespread hypothesis maintained that petals were actually modified leaves. In spite of the scientific advancements in botany over the past 200 years, scientists were unable to convert leaves into each of the flower organs - unable, that is, until this year.

According to an About.com article (1), scientists at the University of Southern California, San Diego (UCSD) have successfully transformed plant leaves into petals. Funding from the National Science Foundation, the National Institute of Heath, and the U.S. Department of Agriculture made the research and realization of this transmutation possible.

Scientists have been attempting this metamorphosis for a number of years without success. "This is a very exciting discovery," stated Martin f. Yanofsky, a professor of Biology at the UCSD and a member of the research team responsible for the successful discovery. Yanofsky made this scientific breakthrough along with UCSD biologist Soraya Pelaz and in cooperation with Roasalinda Tapia-Lopez and Elena R. Alvarez-Buylla of the Nation Autonomous University of Mexico in Mexico City. Yanofsky went further to remark that "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"(2).

Typical flowers consist of four rings. The outermost ring is comprised of sepals. The next ring is one of petals, and the ring inside of that is made up of stamens (the male reproductive structures). At the center are the carpels, which are the female reproductive elements.

The team published a paper in the journal Nature that described their discovery of five genes were necessary for the transformation from leaf to petal to occur. Three of these five genes exist as a trio of identical genes that produce and abnormality that scientists have been trying to understand for close to 2000 years. This abnormality is known as a "double flower" and is the result of the petals, stamens, and carpels of the flower being converted into sepals. The team established that this phenomenon that produced a flower within a flower within a flower "continues indefinitely in plants with a trio of mutated SEP genes - or at least until the smallest organs of the flower can't be detected"(2). The discovery made by the UCSD team resulted from their studies of a mustard plant, Arabidopsis, that two of the SEP genes, when paired with three other genes responsible for floral development, are "sufficient to convert leaves into petals"(2). The three genes contingent to the process other than the SEP genes are not typically expressed in leaves and so producing plants capable of expression of all five genes was by no means an easy task. Yanofsky and his colleagues devoted an entire year to isolate plants that expressed all five genes concurrently in leaves. After a year of experimentation, they were able to simultaneously activate all five genes required for the transmutation. (Click here), for illustration of a successfully altered plant where all five genes are expressed resulting in the development of seemingly normal petals in place of leaves [photo credit: Soraya Pelaz, UCSD]. Yanofsky pointed out that, "each of the genes we work with is normally active only in the flower. So we had to use genetic tricks to turn on five different genes in leaves where they are normally not active"(2). He sums it up by stating, "it wasn't easy, but the result was very satisfying"(2).

The discovery should yield scientists the ability to morph leaves of any plant into petals. This will surely introduce a broad range of plant life that is heightened in its aesthetic appearance but it may also pave the way for a larger supply of commercial medicinal and fragrance products.

This is a very long-awaited and exciting discovery however it is also important to question the evolutionary repercussions of such alterations. Is this man's way of molding life to his liking without consideration of the long-term consequences? Or is it a true breakthrough that will enhance the evolution of plant-life as we know it? These questions will remain unanswered until we are able to observe the effects over an extended period of time. In the meantime, gardens will be brighter and we will be able to enjoy the abundance of color and fragrance that will be byproducts of this discovery.

WWW Sources

2) UCSD Biologists Turn Leaves into Petals , Press release from the University of California, San Diego

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