Leaf development

Insight into the genetic control of leaf development has been gained over the last years thanks to molecular genetic approaches used in a few model species, such as Arabidopsis thaliana. Transcription factors have been identified that control critical steps in leaf development. Their functional analysis has uncovered the molecular mechanisms involved and confirmed a number of classical hypotheses for dorso-ventrality and leaf compoundness, for instance. The switch from indeterminate growth of the shoot apical meristem to the determinate growth of the leaf and pattern formation are transcriptionally controlled and genetic interaction maps have been designed for these processes. Basic mechanisms in model organisms have been compared with those in other species. Variations on the themes explain morphological diversity, such as compound versus simple leaf shape. New technologies, as the so-called systems biology approach, in which not a single gene, but the entire genome is studied in a given genotype, will take the research to the next level