A research team led by Teh-hui Kao, professor of biochemistry and molecular biology at Penn State University, in collaboration with a team lead by Professor Seiji Takayama at the Nara Institute of Science and Technology in Japan, has discovered a large suite of genes in the petunia plant that acts to prevent it from breeding with itself or with its close relatives, and to promote breeding with unrelated individuals. In much the same way that human inbreeding sometimes results in genetic disease and inferior health, some inbred plants also experience decreased fitness, and therefore, have developed mechanisms to ensure that their offspring benefit from hybrid vigor -- the mix that results when genetically distinct members of the same species breed. The team's discovery of the multiple inbreeding-prevention genes will be published on 5 November 2010 in the journal Science. The identification of these genes comes on the heels of Kao's earlier identification of two additional inbreeding-prevention genes in the same plant.
"Humans have mechanisms to prevent inbreeding that are in part cultural," Kao explained. "But a plant can't just get up and move to the next town to find a suitable, unrelated mate. Some other system must be at work." Kao began to unravel the mystery of what he calls a "non-self recognition system" in the mid 1980s by studying the genetic sequence of petunias. Petunias and many common garden plants are hermaphroditic, possessing both male and female reproductive organs, and these reproductive organs are located in close proximity in the same flower. This floral anatomy makes it easy for a plant's pollen to land on itself, resulting in self-fertilization and genetically inferior, inbred offspring. To prevent self-fertilization, many flowering plants, including the petunia, have evolved a strategy called self-incompatibility, or the ability to recognize self and non-self components within both the male and female reproductive organ
|Contact: Barbara Kennedy|