Abstract
Though cyanobacteria have peptidoglycan layer between inner and outer membranes and 9.genes for its synthesis, this wall structure has not yet been observed in plastids of green plants. We found all homologous genes for the peptidoglycan synthesis pathway in moss Physcomitrella patens. Each disruptant of MurE and PBP genes displayed indistiguishable phenotype whose characters are larger size and decreased number chloroplasts in comparison with those of wild type plants. The chloroplasts morphology of mutants appeared to be similar to those observed in the cells treated with beta-lactam antibiotics. We speculate that moss P. patens harbors peptidoglycan layer between inner and outer envelopes and is indispensable to chloroplast divison.GFP fusion assay revealed that PpMurE and PpPBP are transported to chloroplasts. Furthermore, the complementation test that introduced Anabaena homologous gene into P. patens murE mutant confirmed that Anabaena MurE is functionally identical to those of P. patens.
