First Transgenic Papaya Genome Draft

A collaboration of research institutions from the United States and China has produced the first draft of the papaya genome. The draft, which spelled more than 90 percent of the plant’s gene coding sequence, is also the first for a genetically modified plant. The researchers studied ‘SunUp’, a transgenic variety resistant to the papaya ring spot virus. Papaya is now the fifth angiosperm to have its genome sequenced, after Arabidopsis, rice, poplar and grape. An article in the journal Nature reports details of the accomplishment.

The draft is expected to shed light on the evolution of flowering plants. The findings indicate that papaya took a different evolutionary path after its divergence from Arabidopsis 72 million years ago. Although the papaya genome is three times larger than that of Arabidopsis, it contains fewer genes especially those involved in disease resistance. Papaya share with poplar an increased number of genes associated with cell expansion, starch production and lignin biosynthesis, consistent with the evolution of a tree-like habit.

 Detailed information on the precise location of transgenic modification in the plant is expected to help lower regulatory barriers in countries like Japan, where import of virus-resistant papaya is prohibited.

The abstract of the paper is available at http://www.nature.com/nature/journal/v452/n7190/abs/nature06856.html For more information visit http://www.news.uiuc.edu/news/08/0423papaya.html