Abstract
The cyclobutane prymidine dimer (CPD) is one of the major UV-induced photodamage and can be reversed to two monomer pryimidines by photorepair or excision repair. Repair, which is mediated by photolyase, is the major pathway in plants. No photorepair system has been reported to operate in chloroplasts in Arabidopsis and spinach. However, it has still been open in rice. We report here the intercellular localization of CPD photolyase in rice (cv. Sasanishiki) leaves.
Each nucleus- and chloroplast-rich fraction was obtained from leaves by sucrose density gradient centrifugation. Chlorophyll content and NADP-G3P-dehydrogenase activity were used as a marker for chloroplasts. Amounts of rbcS and rbcL measured by QPCR were also applied as a marker for nuclei and chloroplasts, respectively. Higher CPD photorepair activity was observed in nucleus-rich fraction, but not chloroplast-rich fraction. It was evident that little or no CPD photolyase was involved in chloroplasts in rice.
