Abstract:

Five rice (Oryza sativa L.) cultivars, widely planted in South China, were grown in greenhouse with or without supplemental UV-B radiation at level of 13.6 kJ·m-2·d-1. After 15 day-UV-B treatment, significant intraspecific differences were observed in plant height, photosynthetic rate and total biomass. Based on the total biomass accumulation, cultivar “Tesanai” was found to be the most sensitive, and cultivar “Luhuangzhan” was the most tolerant species to UV-B radiation. UV-B induced cyclobutane pyrimidine dimer (CPD) in rice DNA were quantified by ELISA with specific monoclonal antibody. CPD accumulations in DNA extracted from 5 rice cultivars were remarkably increased by UV-B radiation, and it was confirmed that there was a strong positive correlation between CPD accumulation and the inhibition of total biomass. Photorepair was proved to be the predominant mode of CPD repair in UV-B irradiated rice. Light-dependent removal of CPD was very fast as compared with dark repair. Different levels of CPD accumulation among rice cultivars were related with different capacity of CPD photorepair. Capacity of light-dependent CPD removal may play an important role in UV-B resistance of rice.

环丁烷嘧啶二聚体累积与水稻UV-B 敏感性的关系
李韶山¹ 王艳² 王小菁³  宾金华³ 刘颂豪¹

（1. 华南师范大学激光生命科学研究所，广州510631; 2. 暨南大学生命科学和技术学院，广州510632；
3.  华南师范大学生物系，广州510631）

摘要：利用单克隆抗体ＥＬＩＳＡ，研究了ＵＶ－Ｂ对水稻ＤＮＡ中环丁烷嘧啶二聚体（ＣＰＤ）的诱导形成及其光、暗修复，并对ＣＰＤ累积与水稻ＵＶ－Ｂ敏感性的关系进行了分析。结果表明，我国南方的５个水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）品种经１３．６ｋＪ·ｍ＾－２·ｄ＾－１ＵＶ－Ｂ处理１５ｄ后，在株高、生物量光合作用等方面表现出明显的品种间差异。不同品种水稻的ＤＮＡ中ＣＰＤ累积比对照组明显增加，且敏感品种ＣＰＤ的累积比抗性品种显著提高。统计分析证实，CPD的累积与生物量的抑制呈显著正相关（ r2=0.622）。UV-B 诱导的水稻DNA中CPD 的清除以光修复为主，不同品种CPD 暗修复能力相似，而光修复能力存在明显差异。根据以上结果推测，不同水稻品种UV-B敏感性与GPD 光修复能力的差异有关。
关键词： 环丁烷嘧啶二聚体（GPD）；DNA 修复；水稻；UV-B 敏感性

Key words: cyclobutane pyrimidine dimer (CPD), DNA repair, rice, UV-B sensitivity