Arabidopsis in Planta Transformation. Uses, Mechanisms, and Prospects for Transformation of Other Species

The ability to move DNA into an organism and thereby alter its phenotype is central to both basic and applied molecular biology. Transformation is a simple task with Escherichia coli or Saccharomyces cer- evisiae, but is usually more difficult with multicellular eukaryotes and can be particularly challenging with some important plant species. However, for Arabi- dopsis, in planta transformation methods have been developed that are incredibly simple. Attempts to apply in planta transformation methods to other plant species have often failed. This may be due in part to a poor understanding of the mechanisms that underlie the successful Arabidopsis transformation method. Studies of Arabidopsis transformation have accordingly been pursued, and three groups have recently published relevant findings. Successful in planta transformation of the legume Medicago trunca- tula was also reported recently, showing that the method can be adapted to other species. The cellular target for transformation of M. truncatula may differ somewhat from the target in Arabidopsis. The above findings may guide future efforts to improve trans- formation of other plant species. This update opens by briefly reviewing transfor- mation protocols that avoid tissue culture, and their impressive utility. Recent findings concerning Arabi- dopsis and M. truncatula transformation are then de- scribed. The review closes by commenting on possi- ble avenues for improvement of transformation in other plant species.