不同镉积累基因型烟草根系镉螯合能力差异及相关基因分析  

Differences of Root System's Cadmium Chelating Ability Between Two Tobacco Genotypes of Different Cd Accumulating Pattern and Analysis of Related Genes Thereof

作　　者：商慧文 陈江华 郭园园[1] 程功[2] 周会娜[1] 戴华鑫[1] 翟妞[1] 张艳玲[1] 

机构地区：[1]中国烟草总公司郑州烟草研究院,郑州450001 [2]许昌市烟草专卖局,河南省许昌市461000 [3]中国烟叶公司,北京市100055

出　　处：《烟草科技》2014年第12期62-66,共5页Tobacco Science & Technology

基　　金：中国烟草总公司郑州烟草研究院科技项目“典型烟区土壤环境质量评价及监测监控研究”(112008CZ0310)

摘　　要：为探讨烟草根系镉液泡截留的基因型差异机理,采用苗期水培试验,研究了不同镉积累模式的两种基因型烟草[普通烟草品种K326和黄花烟草(N.rustica)]根系镉螯合能力和相关基因的表达差异。结果表明:1镉处理前后还原型谷胱甘肽(GSH)和植物螯合肽(Phytochelatins,PCs)出现此消彼长的现象。与对照相比,1μmol/L镉诱导处理导致K326和黄花烟草根系总非蛋白巯基(NPT)含量(质量分数)和PCs含量(质量分数)分别升高45.89%,57.75%和55.58%,84.00%,GSH含量(质量分数)降低10.70%和62.09%。镉处理前后黄花烟草GSH和PCs的变幅明显高于K326。21μmol/L镉诱导处理促进烟草根系中的镉由交换态向螯合态转变,并且促使PCs向高分子量结合态转变。黄花烟草的转化能力高于K326。3对照处理中两基因型烟草根系螯合物中高分子量螯合物(High-molecular-weight chelation,HMW)和低分子量螯合物(Low-molecular-weight chelation,LMW)组分约各占一半。1μmol/L镉诱导条件下,K326中HMW含量(体积分数)占总量的77.43%,黄花烟草中镉几乎全部以HMW形态存在。在镉诱导条件下黄花烟草根系镉向螯合态转化能力和结合能力均明显高于K326,说明根系镉螯合能力的差异是导致黄花烟草和普通烟草镉积累差异的原因之一。4黄花烟草根系植物螯合肽合成酶1基因(Phytochelatin synthase 1,PCS1)的表达对镉具有高度敏感性,与对照相比,1μmol/L镉处理下PCS1的表达量增加257.33%,而镉处理对K326中PCS1的表达影响不大。In order to explore the genotype difference mechanism of Cd vacuole interception in tobacco root systems, hydroponic seedling experiments with different Cd treatments were carried out to study the differences of root system Cd chelating ability and related genes expression between two tobacco genotypes （K326 and N. rustica）. The results showed that： 1） After Cd treatments, GSH decreased, while phytochelatins （PCs） increased. Comparing with the control, the contents of total non-protein thiol （NPT） and PCs in the roots of K326 and N. rustica in the treatment of 1 μmol/L Cd increased by 45.89%, 57.75% and 55.58%, 84.00%, while GSH content decreased by 10.70% and 62.09%, respectively. The change of GSH and PCs caused by Cd treatment was more significant in N.rustica than in K326. 2） Cd treatment promoted Cd in roots transforming from exchangeable state into chelated state, and promoted PCs transforming into high-molecular-weight bound state （HMW）. Notably in N. rustica. 3） In the control, HMW and LMW each accounted roughly for half of the root system chelates in K326 or N. rustica. However, induced by the treatment of 1 gmol/L Cd, HMW accounted for 77.43% of root chelates in K326, and almost all Cd was in the form of HMW state in N.rustica. Under Cd inducing conditions, the transition ability of Cd to chelated state and the binding ability were significantly higher in N. rustica than in K326, it indicated that the difference of roots＇ Cd chelating ability was one of the reasons causing the difference of Cd accumulation between K326 and N. rustica. 4） PCS1 expression in the roots of N. rustica was highly sensitive to Cd, and increased by 257.33% in the treatment of 1 tamol/L Cd; while PCS1 expression in K326 was not affected significantly by Cd treatment.

关 键 词：镉 普通烟草 黄花烟草 根系 植物螯合肽 PCS1 

分 类 号：S572.01[农业科学—烟草工业]