Significant advances in our understanding of plant development at the molecular level, and the relative ease with which stably transformed plants can now be produced, have enabled the design of recent experiments for assessing the function of regulatory genes in transgenic plants. These experiments, often involving ectopic expression or over-expression of transcription factors, have revealed that the manipulation of regulatory genes can lead to dramatic changes in plant traits, a process that may now be tailored to the biotechnological development of novel plant characters. The directed expression of transcription factors offers selective control of plant metabolism and development and may also be used to improve metabolic productivity through the modification of development.