XVI International Botanical Congess

The shoot apical meristem is a center of plant development, but the molecular mechanisms of its initiation and maintenance are yet to be revealed. The moss, Physcomitrella patens is suitable for the study in its simple organization and easiness of molecular analyses using gene targeting. Based on cell lineage analyses, the shoot apical cell is likely to be determined at one or two cell stage in the bud development. A leaf is originated from a single cell and the cell lineage was traced. Homologues of MADS, LFY, AP2, KNOX, and HD-Zip genes, which have important roles in development around shoot meristem in Arabidopsis, were cloned and characterized in P. patens. Tagged mutant library using transposon-mediated shuttle mutagenesis and gene and enhancer trap systems were established to screen the genes involved in shoot development.