Marker-free Transgenic Cassava Plants

Scientists at the Department of Biotechnology, Faculty of Science, Mahidol University in Bangkok, Thailand have successfully generated marker-free transgenic cassava plants. The efficacy of the ipt-type Multi-Auto-Transformation (MAT) vector system to transform the extensively grown cassava cultivar "KU50" was evaluated. This system utilizes the isopentenyltransferase (ipt) gene as morphological marker for visual selection of transgenic lines. When transforming KU50 cassava cultivar with two different ipt-type MAT vectors, transformation frequency at 19-21% was observed. This is the first demonstration of the efficacy of Rint/RS system in promoting excision of ipt marker gene in cassava specie, with the consequent rapid production of marker-free transgenic plants.

The high efficiency of this system should facilitate pyramiding a number of transgenes by repeated transformation without having to undergo laborious, expensive and time-consuming processes of sexual crossing and seed production. The generation of marker-free, thus environmentally safe, genetically modified cassava clones should also ease public concern regarding the use of transgenic cassava in both food and nonfood industries.

More information available at the Biosafety and Biotechnology Information Center in Thailand at http://www.safetybio.agri.kps.ku.ac.th/index.php?option=com_content&task=view&id=5688&Itemid=47 .