Unorthodox Defense in a Model Plant
Cathy Lundmark · BioScience · 2005
Thale cress (Arabidopsis thaliana) may be a small weed, but it's a big deal in the world of plant genetics. Its compact size, short life cycle, relatively small genome, and supposed dearth of genetic redundancy made Arabidopsis the model organism of flowering plants and the first plant chosen for genome sequencing. The sequence was completed in 2000. Through the work of geneticists at Purdue University, the tiny plant is in the spotlight again thanks to a mutant with a mysterious mechanism for reverting to wild type. Susan Lolle, Robert Pruitt, and colleagues have isolated and studied a mutation,“hothead,”that causes tissues of the developing plant to fuse. They have discovered that selfed homozygous hothead mutants produce heterozygous wild-type offspring at a low but significant rate (4 to 8 percent). In the 24 March Nature, the authors show that, somehow, the revertants restored the gene missing from their parents but present in their grandparents or great-grandparents.