采用半定量反转录聚合酶链式反应(RT-PCR)技术,以18S rRNA为内参基因,研究了Cu胁迫对拟南芥(Arabidopsis thaliana)幼苗错配修复相关基因(MLH1、MSH2、MSH3、MSH6、MSH7)表达的影响,并结合幼苗的形态和生理指标,选取Cu胁迫敏感的生物标记物。结果表明,Cu处理10 d后,对拟南芥种子发芽率、地上部鲜重及叶绿素含量的影响不大; 根的长度明显受到抑制; 拟南芥幼苗地上部可溶性蛋白质含量随着Cu浓度增加明显降低; 5个错配修复相关基因的表达均受到不同程度的抑制,Cu浓度与拟南芥幼苗上述指标之间存在明显的剂量-效应关系。以上结果表明,地上部可溶性蛋白含量变化与上述错配修复相关基因表达量的改变趋势一致,且均对Cu胁迫较敏感,可以作为检测Cu污染对植物遗传毒性效应的生物标记物。
By using semi-quantitative reverse transcriptionpolymerase chain reaction (RT-PCR), and with 18S rRNA as the internal standard gene, this paper studied the effects of copper (Cu) stress on the expression of DNA mismatch repair genes (MLH1, MSH2, MSH3, MSH6, and MSH7) in Arabidopsis thaliana plantlets, and, in combining with the morphological and physiological indices of the plantlets, the sensitive biomarkers of Cu stress were selected. The results showed that under Cu stress (0.5, 1.0, and 2.0 mg·L-1) for 10 days, no significant changes were observed in the seed germination percentage, shoot fresh mass, and chlorophyll content, but the root length was obviously inhibited, and the shoot total soluble protein content and mismatch repair genes expression decreased with increasing concentration of Cu. An obvious dose-effect relationship existed between the Cu concentration and the above-mentioned indicators of A. thaliana plantlets. The results indicated that the change trend of the shoot total soluble protein content was similar to that of the mismatch repair genes expression, which were all sensitive to the Cu stress and could be served as the potential and useful biomarkers for the detection of genotoxic effects of Cu pollution on plants.