盐胁迫下花花柴miR398对Cu/Zn超氧化物歧化酶基因的调控研究

植物miRNA能够参与盐胁迫下基因表达的调控。在盐胁迫条件下盐生植物花花柴miR398(KcmiR398)呈现显著性差异表达,为了探讨miR398的靶基因及其对靶基因的调控方式,通过生物信息学分析(http://plantgrn.noble.Org/psRNATarget/),预测KcmiR398的靶基因分别为Cu/Zn超氧化物歧化酶(SOD)基因CSD1和CSD2。利用RACE技术从花花柴中克隆到CSD1和CSD2基因全长序列,分别命名为KcCSD1和KcCSD2。qRT-PCR结果表明:(1)KcmiR398在盐胁迫的花花柴茎中上调表达,在新叶中下调表达;KcCSD1在盐胁迫的老叶中上调表达,而在老茎和根中下调表达;KcCSD2在盐胁迫的老茎和根中上调表达。(2)300mmol/L NaCl胁迫24~48h,KcmiR398与对照无显著差异;KcCSD1的表达为对照的3倍以上,而KcCSD2的表达没有显著差异。研究表明,花花柴的KcmiR398和KcCSD1、KcCSD2有组织差异性表达,盐胁迫可以影响KcmiR398和KcCSD1、KcCSD2基因的表达以适应盐胁迫产生的氧化危害。

Regulation of Copper-zinc Superoxide Dismutase Gene Expression by miR398 in Karelinia caspica under Salt Stress

Some plant miRNAs are involved in gene expression regulation under salt stress.KcmiR398,a miRNA from halophytic Karelinia caspica,presented a significant differential expression under salt stress.In order to investigate the target genes of KcmiR398 and its regulatory effect to the target genes,we performed online bioinformatics analysis (http://plantgrn.noble.Org/psRNATarget/),and Cu/Zn superoxide dismutase (SOD) genes CSD1 and CSD2 were predicted as the target genes of KcmiR398.Full length sequences of CSD1 and CSD2 (named KcCSD1 and KcCSD2 respectively) were cloned by using RACE technology.qRT-PCR results showed that:(1)The expression of KcmiR398 was up-regulated in the stems of the salt-stressed K.caspica,but down-regulated in the new leaves;The expression of KcCSD1 was up-regulated in the old leaves of the salt stressed plant,but down-regulated in the old stems and roots;The expression of KcCSD2 was up-regulated in both old stems and roots of the stressed plant.(2)When plant stressed with 300 mmol/L NaCl for 24~48 h,the expression of KcmiR398 showed no significant difference compared to the control;the expression of KcCSD1 was more than 3-fold of that of control;whereas the expression of KcCSD2 showed no significant difference with salt treatment.These results indicated that the expression of KcmiR398,KcCSD1 and KcCSD2 were tissue differential,and the expression of KcmiR398,KcCSD1 and KcCSD2 was influenced by salt stress,which makes K.caspica resist to the damage of oxidation caused by salt stress.