Research Notes

Courtesy University of California, San Diego Top, five genes convert leaves to petals; bottom, only four genes are needed to convert leaves to petals Leaves into Petals In what just might be the botanical equivalent to the ancient alchemist's dream of transmuting iron into gold, biologists have discovered how to genetically convert the leaves of flowering plants into petals, an achievement that holds commercial as well as scientific implications (S. Pelaz et al., "Conversion of leaves into petals in Arabidopsis," Current Biology, 11[3]:182-4, February 2001). "It has been known for the past decade that two genes--called A and B genes, for simplicity (different plant's A and B genes have specific names)-- are required for a petal to form, but they were not sufficient to convert a leaf into a petal," explains Martin F. Yanofsky, professor of biology at the University of California, San Diego, who conducted the study with UC-San Diego biologist Soraya Pelaz in collaboration with Rosalinda Tapia-Lopez and Elena R. Alvarez-Buylla of National Autonomous University of Mexico (NAUM). It turned out that a trio of genes, known as SEP genes, which Yanofsky and colleagues at UC-San Diego discovered last year, was the missing link. It was a "grueling" task, but with patience and "genetic tricks," they managed to turn on the five different genes in the leaves of a mustard plant, Arabidopsis, and normal-looking petals appeared in place of leaves. "The result was very satisfying," says Yanofsky, senior author of the report. Basic science aside, "this opens the door to tremendous novelty in all flowering plants," he adds, something that will be highly appealing to the cut-flower industry. "You could have, for example, a typical long stem red rose, and instead of green leaves along the stem, you could convert them into yellow petals. You could alter and create thousands of dramatic new varieties for any flowering plant." Other applications would include enhanced pigment production for various products from eye shadows to fabrics to paints. In addition, any medicinal substances that may be found in plant petals could be produced in greater quantities. There is still, however, work to be done. The goal now, says Yanofsky, is to understand everything about how flowers form, "from the initiation to the development of all the flower organs, which are very complex." --A.J.S. Rayl Deciphering E. coli In sequencing the genome for the Escherichia coli 0157:H7, researchers at the University of Wisconsin-Madison have found 1,387 genes that distinguish it from the harmless form that lives in human intestines (N.T. Perna et al., "Genome sequence of enterohaemorrhagic Escherichia coli O157:H7N," Nature, 409:529-33, Jan. 25, 2001). Not all these genes "are directly involved with virulence," says Perna, an assistant professor in the department of animal health and biomedical science. But one clear goal is to find ones that are responsible for causing illness. "One of the things to do is to consider whether any of these genes offer a good way to make a vaccine. A cattle vaccine would be a sensible way to do it," says senior author Frederick Blattner. The bacteria typically sicken and can kill people who eat contaminated meat. Another possible treatment route, says Blattner, is developing drugs that block a step or steps in the assembly of the proteins coded for by the genes. Comparing these approximately 1,400 genes to those in existing databases, about 40 percent are similar to those found in other bacterial pathogens, says Perna. "Another 40 percent are parts of bacteriophages," she says, indicating that phages play a role in transporting the genes from one bacterial type to another. "The other 20 percent I find really fascinating because I have no idea what they may be. Nothing like them has ever been seen before." --Harvey Black

Research Notes

Leaves into Petals

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