ABSTRACT
Plant transformation is an indispensable tool, both for the experimental investigation of gene function and for the improvement of plants either by enhancing existing traits or introducing new ones (1-3). It is now possible to introduce and express DNA stably in nearly 150 different plant species. Many aspects of plant physiology and biochemistry that cannot be addressed easily by any other experimental means can be investigated by the analysis of gene function and regulation in transgenic plants. This offers an unprecedented opportunity to study the molecular basis of important processes that have been intractable to conventional analysis, such as the complex signal transduction pathways and hierarchies of genetic regulation that underlie plant-microbe interactions, sexual reproduction, and development.
