盐及干旱胁迫对油菜抗氧化系统和RbohC、RbohF基因表达的影响

以白菜型油菜‘陇油6号’和‘天油2号’为试验材料,经MAPK抑制剂U0126、H₂O₂清除剂DMTU、NADPH氧化酶抑制剂DPI和IMD预处理后再分别进行盐胁迫、PEG-6000模拟干旱胁迫,研究其对两种油菜幼苗活性氧、抗氧化酶活性和RbohC、RbohF基因表达的影响.结果表明: 盐胁迫和PEG-6000模拟干旱胁迫下,两种白菜型油菜中H₂O₂积累量上升,O₂^-·积累量下降,抗氧化酶(超氧化物歧化酶SOD、过氧化氢酶CAT、抗坏血酸过氧化物酶APX和谷胱甘肽还原酶GR)活性和RbohC、RbohF基因表达均升高.与单独胁迫处理相比,两种油菜O₂^-·积累、抗氧化酶活性和RbohC、RbohF基因的表达量均明显降低,经DMTU、DPI和IMD预处理后再分别进行盐和干旱胁迫,H₂O₂积累量下降,但U0126预处理后再进行胁迫处理,H₂O₂积累量上升.说明NADPH氧化酶、MAP激酶级联途径、H₂O₂参与了盐、干旱胁迫下活性氧产生、抗氧化酶活性变化和RbohC、RbohF基因表达的调控.

Effects of salt and drought stresses on antioxidant system and RbohC and RbohF genes expression in Brassica campestris

To investigate the effects of salt stress and PEG-6000 simulating drought stress on the active oxygen and antioxidant enzyme activities, as well as the expression level of RbohC and RbohF genes, the seedlings of two Brassica campestris, Longyou 6 and Tianyou 2, were treated with U0126 (a MAPKK inhibitor), DMTU (a H₂O₂ scavenger), as well as DPI and IMD (NADPH oxidase inhibitors). The results showed that under both stresses, H₂O₂ accumulation as well as antioxidant enzyme (SOD, CAT, APX, GR) activities and the expression of RbohC and RbohF genes increased, while O₂^-· accumulation decreased. The O₂^-· accumulation, antioxidant enzyme activity and RbohC and RbohF genes expression in both varieties all significantly decreased. Compared to seedlings with on pretreatment before salt and PEG-6000 simulating drought stress, the accumulation of H₂O₂ decreased in seedlings pretreated with DMTU, DPI and IMD. However, the accumulation of H₂O₂ increased in those pretreated with U0126. Those results indicated that the NADPH oxidase, MAP kinase cascade and H₂O₂ were involved in the regulation of active oxygen production and antioxidant enzyme activity, as well as the expression of RbohC and RbohF under salt stress and drought stress.