镉胁迫对拟南芥幼苗基因组DNA多态性的影响

Effects of cadmium stress on DNA polymorphism of genome in Arabidopsis thaliana seedlings

应用随机扩增多态性DNA(RAPD)技术,检测了镉(Cd)胁迫对拟南芥幼苗叶片DNA多态性的影响,并结合其形态和生理指标,选取Cd污染敏感的生物标记物。结果表明:0.125～3.0mg·L-1Cd处理21d后,拟南芥幼苗叶片的可溶性蛋白质含量随Cd浓度的增加呈倒U字型曲线变化,但其鲜重和叶绿素含量变化均不明显;12条寡核苷酸引物中,有5条引物扩增出稳定、特异的PCR产物;拟南芥幼苗叶片基因组的RAPD图谱中,对照组RAPD图谱中分辨出44条清晰的条带;Cd胁迫使拟南芥幼苗叶片基因组的RAPD图谱发生了改变,包括条带的增加、缺失和条带荧光强度的改变,且与Cd剂量相关。实验证明,Cd影响基因组模板的稳定性,即DNA多态性对Cd污染敏感,可以作为检测Cd污染及其相关生物学效应的潜在生物标记物。

By using random amplified polymorphic DNA （RAPD） technique,the DNA polymorphism of genome in Arabidopsis thaliana seedlings leaves under Cd stress was studied,and,in combining with leaf morphological and physiological indices,the sensitive biomarkers indicative of Cd stress were chosen.After treated with 0.125-3.0 mg Cd·L-1 for 21 days,the soluble protein content in A.thaliana seedlings leaves had an inverted U-shape increase with increasing Cd concentration,but no significant changes were observed in leaf fresh weight and chlorophyll content.Of the 12 decamer oligonucleotide primers tested,only 5 gave specific and stable results.In the control,44 bands of the RAPD fingerprints from the leaves were easily distinguished.The changes in the RAPD fingerprints under Cd stress included the variation of band intensity,loss of normal bands,and appearance of new bands,in comparison with the control.In addition,the changes were dose-dependent.The above results showed that the genomic template stability was significantly affected by Cd stress,and the DNA polymorphism was sensitive to Cd stress.Thereby,the DNA polymorphism detected by RAPD technique could be used as a potential biomarker assay for the detection of Cd pollution and its related biological effects.