Romancing the Wild Mustard: Arabidopsis thaliana

During the week of Dec. 10, 1999, an international consortium announced that it had completed the first genome sequence of a higher plant. This small weed, Arabidopsis thaliana, according to a report in Science, could offer a window into the genetic makeup of all plants, including important crops. One scientist predicted that the genome sequence might lead to the development of crops better suited to developing countries, plants designed to soak up more carbon dioxide and other applications yet to be imagined.

The genome sequence produced by the consortium of six international sequencing teams on three continents pulled off a small coup. The sequence produced was more accurate than that of any multi-cellular organism published previously. Plants, it appears, might be much more complex than many biologists have imagined.
Arabidopsis, it seems, has some 25,000 genes, compared with 13,600 in the fruit fly and an estimated 30,000 in humans. Moreover, Arabidopsis has homologues of many important human proteins involved in disease and cancer. Among these 100 disease-causing counterparts in humans are the genes involved in cystic fibrosis and breast cancer. Still, we have a long way to go: Nearly half of all Arabidopsis genes have unknown functions.

The National Science Foundation 2010 Project, a 10-year effort by the plant biology community, envisions that in a decade every gene in Arabidopsis will have been subjected to one or more experiments in which the gene is inactivated or over-expressed. The resulting phenotypes then will be examined by all available criteria. Gene-expressed proteins will be localized and comprehensive information made available as to how they are modified and, perhaps, interact.

Thus, Arabidopsis is a model for all flowering plants. It is also a member of the "Security Council" of models: yeast, Drosophila, C. elegans, mouse. And like these models, Arabidopsis will inform and speed discovery in all of biology.