Exploring plant biodiversity: the Physcomitrella genome and beyond.

For decades, plant molecular biology has focused on only a few angiosperm species. Recently, the approximately 500mega base pairs (Mb) of the haploid Physcomitrella patens genome were sequenced and annotated. Mosses such as P. patens occupy a key evolutionary position halfway between green algae and flowering plants. This draft genome, in comparison to existing genome data from other plants, allows evolutionary insights into the conquest of land by plants and the molecular biodiversity that land plants exhibit. As a model organism, P. patens provides a well-developed molecular toolbox, including efficient gene targeting in combination with the morphologically simple moss tissues. We describe current as well as future tools for P. patens research and the prospects they offer for plant research in general.