【摘要】 本研究以拟南芥野生型(WT)、AtJ8缺失突变体(j8)和过表达株系为材料,探究AtJ8蛋白在拟南芥响应铜胁迫过程中的生理功能和分子机制。结果表明, AtJ8基因受铜胁迫诱导表达。铜胁迫下,与WT和j8突变体相比,过表达AtJ8植株具有较高的萌发率、叶绿素含量和鲜重,且根和幼苗生长发育的抑制程度较小。铜胁迫下,不同株系叶片内铜的含量没有明显差异,而过表达植株体内过氧化氢(H2O2)和超氧阴离子(O2.-)的含量显著低于WT和j8突变体,超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性则显著高于WT和j8突变体。同时,蛋白免疫印迹结果显示,铜胁迫下,过表达植株中D1蛋白含量显著高于其他两个株系。由此说明, AtJ8通过维持铜胁迫下较高的抗氧化酶活性来缓解活性氧(ROS)的过量积累,进而缓解光系统II (PSII)所受的光抑制,以此来增强拟南芥的铜胁迫抗性。更多还原

【Abstract】 In this study, Arabidopsis thaliana wild-type, AtJ8 deletion mutant(j8) and overexpressed lines were used as materials to explore the physiological function and molecular mechanism of AtJ8 in response to copper stress. The results showed that AtJ8 gene was induced by copper stress. Under copper stress, compared with WT and j8 mutants, overexpressed lines had higher germination rates, chlorophyll contents and fresh weight, and lower inhibition degrees of root and seedling growth and development. Under copper stress, there was no significant difference in copper contents among WT, j8 and overexpressed lines, and the contents of hydrogen peroxide(H2 O2) and superoxide anion(O2.-) in overexpressed plants were significantly lower than those of WT and j8 mutants, but the activities of superoxide dismutase(SOD) and catalase(CAT) were significantly higher than those of WT and j8 mutants. Meanwhile, Western blot results showed that D1 protein contents in overexpressed lines were significantly higher than those of WT and j8 mutants under copper stress. Therefore, AtJ8 alleviates the excessive accumulation of reactive oxygen species(ROS) by maintaining high antioxidant enzyme activities under copper stress, and then alleviates the photoinhibition of photosystem II(PSII), so as to enhance the copper stress tolerance of Arabidopsis.更多还原