转GST和CAT1基因水稻根系抗氧化系统对干旱高温胁迫的响应(英文)

Response of Antioxidant System to Drought and Heat Stress in Transgenic Rice Roots Carrying GST and CAT1

以携带谷胱甘肽转移酶(GST)和过氧化氢酶(CAT1)的转基因水稻和非转基因水稻(Oryza sativa L.)品种‘中花11’的根系为材料,比较分析了二者在PEG6000、38℃及PEG6000和38℃复合胁迫下抗氧化系统特别是抗坏血酸-谷胱甘肽循环系统的变化。结果显示,6%PEG处理时,转基因水稻的CAT、GST、超氧化物歧化酶(SOD)、谷胱甘肽还原酶(GR)和脱氢抗坏血酸还原酶(DHAR)的活性都显著高于非转基因水稻;38℃处理时,前者的CAT、GST、SOD和GR的活性则显著低于后者;6%PEG和38℃复合处理时,前者的CAT、GST、抗坏血酸过氧化物酶(APX)和DHAR的活性也都显著高于后者,但前者的SOD和GR活性则显著低于后者。6%PEG诱导的转基因水稻根系的抗坏血酸氧还状态显著低于非转基因水稻,但二者的谷胱甘肽氧还状态无显著差异;而6%PEG和38℃同时处理时,转基因水稻的谷胱甘肽氧还状态则显著高于非转基因水稻,但二者的抗坏血酸氧还状态差异不显著。研究发现,干旱和高温复合胁迫时,转基因水稻和非转基因水稻的抗氧化组分的变化均不等于这2种单一胁迫的叠加;GST和CAT1基因的转入对水稻抗氧化系统内源功能相关组分尤其是抗坏血酸-谷胱甘肽循环系统产生了一定的影响,两种水稻的根系可能利用不同的抗氧化组分调节机制对这些胁迫做出应答。

A comparative study on changes of antioxidant system,in particular,the ascorbate-glutathione cycle in transgenic rice carrying glutathione-S-transferase（GST,EC.2.5.1.18）and catalase1（CAT1,EC.1.11.1.6）and non-transgenic rice（Oryza sativa L.Zhonghua No.11）roots exposed to heat（38°C）or drought（PEG 6000）and their combination was conducted.Data showed that the activities of CAT,GST,superoxide dismutase（SOD,EC.1.15.1.1）,glutathione reductase（GR,EC.1.6.4.2）and dehydroascorbate reductase（DHAR,EC.1.8.5.1）were significantly higher in the transgenics than that in non-transgenics after being treatment with 6% PEG.In contrast,significantly lower activities of CAT,GST,SOD and GR were observed in the transgenics compared with non-transgenics following heat（38℃）stress.When subjected to the combined 6% PEG and heat stress,the CAT,GST,ascorbate peroxidase（APX,EC.1.11.1.11）and DHAR activities were significantly higher but the SOD and GR activities were lower in the transgenics than that in non-transgenics.Moreover,6% PEG induced significantly lower redox state of ascorbate in the transgenics in comparison with non-transgenics,but no significant difference of the glutathione redox state was found between them.However,the combined 6% PEG and heat stress caused significantly higher redox state of glutathione in the transgenics than that in non-transgenics,while no significant difference of the ascorbate redox state occurred between them.It was found that the changes of the antioxidant components caused by the combined PEG and heat stress are not simply the sum of the changes induced by the two stresses applied individually,whatever in the transgenic or in non-transgenic rice roots.These results indicated that the GST and CAT1 transgene influences the function-linked antioxidant components especially the whole ascorbate-glutathione cycle following the applied these stresses.Our results also implied that different regulatory mechanisms of the antioxidant components may be used by the transgenic and non-transgenic rice roots for these stress responses.