Abstract
UV radiation induces two types of pyrimidine dimers between adjacent pyrimidines on the same strand: the cyclobutane pyrimidine dimer (CPD) and the pyrimidine-(6-4)-pyrimidone photodimer [(6-4)pp]. Such damage can be lethal or mutagenic to organisms. Organisms have developed mechanisms for repairing these photodamages. Photoreactivation, which is mediated by photolyase, is the main pathway in rice. We report here the photorepair of (6-4)pp in cvs UV-resistant Sasanishiki and UV-sensitive Norin 1. The fully expanded third leaves which had been irradiated with UVB were exposed to blue light, and the change in (6-4)pp was measured by ELISA. Higher photorepair of (6-4)pp was found in Sasanishiki than in Norin 1, suggesting a possibility that (6-4)pp photolyase besides CPD photolyase is involved in the different sensitivity to UVB in rice.
