UV-B诱导的水稻DNA损伤和修复研究

利用单克隆抗体ELISA,研究了UV-B对水稻DNA中CPDs和6-4PPs的诱导形成,并证实了水稻幼苗中DNA损伤的光修复和暗修复的存在.经UV-B处理的水稻幼苗,DNA中CPDs和6-4PPs的积累随UV-B处理时间的增加而上升.水稻幼苗DNA损伤的暗修复能力较低,24h内仅修复约20～30%.与暗修复相比,DNA损伤的光修复进程较快;CPDs的光修复在20min内可修复50%;而6-4PPs的光修复需要1h才能完成50%修复.以上结果表明,UV-B诱导的水稻DNA损伤的修复以光修复为主,且CPDs和6-4PPs的修复活性与其它植物存在差异.

DNA DAMAGE AND REPAIR IN RICE SEEDLINGS IRRADIATED WITH UV-B

By using monoclonal antibody enzyme-linked immunosorbent assay (ELISA),induction and repair of damage to DNA in rice seedlings irradiated with UV-B were studied in the present paper.UV-B-induced DNA damage,namely,cyclobutane pyrimidine dimers (CPDs) and (6-4) photoproducts (6-4PPs) in rice seedlings were found to be accumulated with increasing time of UV-B treatment.The dark repair of both types of photolesions was confirmed in rice seedlings.Dark repair was less efficient as compared with photorepair,only about (20～30)% of initial damage was removed within 24h.Photorepair of CPDs was very fast,with 50% removal within 20min.By contrast,50% of initial 6 4PPs were removed in 1h.These results indicate that photorepair is the predominant mode of DNA repair in rice seedlings,and repair activities in rice seedlings are different from those in Arabidopsis,in which 6-4PPs are photorepaired more rapidly than CPDs.