De novo shoot organogenesis: from art to science.

In vitro shoot organogenesis and plant regeneration are crucial for both plant biotechnology and the fundamental study of plant biology. Although the importance of auxin and cytokinin has been known for more than six decades, the underlying molecular mechanisms of their function have only been revealed recently. Advances in identifying new Arabidopsis genes, implementing live-imaging tools and understanding cellular and molecular networks regulating de novo shoot organogenesis have helped to redefine the empirical models of shoot organogenesis and plant regeneration. Here, we review the functions and interactions of genes that control key steps in two distinct developmental processes: de novo shoot organogenesis and lateral root formation.