Abstract
Plant organellar DNA must be damaged by UV and reactive oxygen species derived from the respiration and photosynthesis. However, the repair mechanism of the damaged DNA is largely unknown. In bacteria, DNA double-strand break is repaired by recombinational repair where RecA plays an important role. We predicted that plant organelle have similar bacterial-type recombinational repair mechanism, and analyzed such a mechanism in the moss, Physcomitrella patens. We identified a homologue of RecG, which is a helicase involved in the recombinational repair in Escherichia coli, and named PprecG. N-terminal fusion of a putative organellar targeting sequence of the PpRecG to GFP caused targeting of PpRecG to mitochondria and chloroplast, and the expression of PprecG was induced by treating the plants with DNA damaging agents. Null mutation of PprecG resulted in defect in growth and development.
