Abstract
Ultraviolet radiation (UV) is toxic to organisms. Higher plants grown under solar radiation are irradiated with UV at the same time. DNA damages induced by UV, pyrimidine dimers, cause an inhibition and error of DNA replication, leading to mutation. We investigated the specificity of UV-induced mutation in Arabidopsis thaliana with the use of the system for mutation detection in plants we have developed. E. coli rpsL gene introduced into Arabidopsis is a target gene for mutation. Infrequent base substitution mutations of AT to TA and GC to CG were detected in UV-B-irradiated Arabidopsis in addition to GC to AT transitions which are frequently observed in E. coli and mouse skin. Insertion of long sequence was also observed. Mutational spectrum obtained was different from other organisms, suggesting to be specific to higher plants. We are analyzing mutation in Arabidopsis in which CPD photolyase gene was silenced by RNAi.
