Abstract
Mitochondria and plastids in plant cells have their own DNAs (organellar DNAs). Male gametophyte (pollen) consists of vegetative cell and generative cell. The content of these organellar DNAs in both cells is known to decrease during pollen maturation, however, the molecular mechanisms controlling such an organellar DNA metabolism remain to be understood. We screened Arabidopsis mutants in which the organellar DNA, detected by DNA-specific dye (DAPI) staining, are retained in mature pollen grains. Several mutants were isolated in which DAPI-stained signals were observed in the cytoplasm of vegetative cells. Such signals were not observed in wild-type pollen grains. Double staining of DAPI and mitochondrion-preferable dye (DiOC6) revealed that DAPI-stained signals are derived from plastid DNAs but not from mitochondrial DNAs. One of the mutants exhibited the leaf-variegated phenotypes. We will report on the electron microscopy study and the progress of map-based cloning of the responsible genes.
