REPAIR MECHANISMS OF UV-INDUCED DNA-DAMAGE IN SOYBEAN CHLOROPLASTS

In order to better understand the biochemical mechanisms of DNA metabo lism in chloroplasts, repair of UV induced plastome damage in vivo was determined by exposure of soybean suspension cells to UV light and su bsequent quantitation of the damage remaining in nuclear and chloropla st encoded genes with time by quantitative polymerase chain reaction ( QPCR). The kinetics of damage rapir in the nuclear rbcS gene suggest t hat photoreactivation and dark mechanisms are active, while for the pl astome encoded psbA gene only a light-dependent repair process was det ected which is considerably slower than would be expected for photolya se-mediated photoreactivation.