KNOX2 Gene Helps Plants Become Diploid, Study
Researchers have identified a particular gene that regulates the transition between stages of the life cycle in land plants.
AsianScientist (Mar. 5, 2013) - In a study published in Science, researchers have uncovered for the first time a mechanism that regulates the reproduction of plants, providing a possible tool for engineering higher yielding crops.
Plants, in contrast to animals, take different forms in alternating generations - one with one set of genes and one with two sets.
"In animals, the bodies we think of are our diploid bodies - where each cell has two sets of DNA. The haploid phase of our life cycle consists of only eggs if we are female and sperm if we are male. In contrast, plants have large complex bodies in both haploid and diploid generations," said Professor John Bowman, of the Monash School of Biological Sciences.
In this study, researchers in Australia, Japan, and the United States identified a particular gene that regulates the transition between stages of the life cycle in land plants - the haploid and diploid phase.
These two plant bodies often have such different characteristics that until the mid-1800s, when better microscopes allowed further research, they were sometimes thought to be separate species.
By removing a gene known as KNOX2 from moss, they found that it caused the diploid generation to develop as if it was a haploid, a phenomenon termed apospory. The equivalent mutations in humans would be if our entire bodies were transformed into either eggs or sperm.
"Our study provides insights into how land plants evolved two complex generations, strongly supporting one theory put forward at the beginning of last century proposing that the complex diploid body was a novel evolutionary invention", Bownman explained.
Bowman said that there possible applications for the results as mutations in the gene cause the plant to skip a generation. One goal in agriculture is apomixis, where a plant produces seeds clonally by skipping the haploid generation and thereby maintaining the characteristics, such as a high yielding hybrid.
"Gaining a better understanding of the molecular basis of plant reproduction and the regulations of the alternation of generations could provide tools to engineer apomixis - a breakthrough that would be highly beneficial, especially in developing countries," he said.
The article can be found at: Sakakibara K et al. (2013) KNOX2 Genes Regulate the Haploid-to-Diploid Morphological Transition in Land Plants.
Source: Monash University; Photo: Taz-Voll/Flickr/CC.
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