【作者】 徐忠俊；

【导师】 赵凤云；

【作者基本信息】 山东理工大学 ， 生物化学与分子生物学， 2010， 硕士

【摘要】 用不同浓度Cd(NO3)2 (0、0.1、0.3 mM)处理转GST (glutathione-S-transferase)和CAT1 (catalasel)双抗氧化酶基因水稻(Oryza sativa L.,中花11号)和非转基因对照并测定了其根和地上部的抗氧化酶如CAT、GST、SOD (superoxide dismutase)、APX (ascorbate peroxidase)、DHAR (dehydroascorbate reductase)和GR (glutathione reductase)的活性变化。结果显示,转基因水稻的根和地上部的抗氧化酶的变化与非转基因对照的存在明显差异,转基因水稻抗氧化能力的提高是多种抗氧酶之间协调作用的结果。本文进一步分析了,在0.1 mM Cd(NO3)2处理条件下,生长素(IBA)、H2O2(添加AT或DMTU分别增加或减少H2O2)和O2·-(添加DDC或Tiron分别增加或减少O2·-)对水稻(Oryza sativa L.,中花11号)根系生长发育的影响。结果显示,添加IBA和增加H2O2及O2·-含量,都能够促进初生根、不定根和侧根的伸长生长,并增加侧根的数量；然而,抑制生长素的极性运输(添加TIBA)和减少ROS含量,则抑制初生根、不定根和侧根的伸长生长,并减少侧根的数量。利用半定量RT-PCR从基因组水平检测了在这些处理条件下,根系生长素运输(OsPIN 9个)、应答(OsARF25个)、调节(OsPID1个)以及细胞周期(63个)基因家族在转录水平的变化。结果表明,在所检测的98个基因中,有44、48、66和59个基因分别受镉、H2O2、O2·-和生长素的调节。其中受镉和H2O2共同调节的基因有33个；有38个基因既受镉调节又受生长素调节；有44个基因受镉和O2·-的共同调节；有53个基因受生长素和O2·-的共同调节；有36个基因受镉、生长素和O2·-的共同调节；还有29个基因受镉、生长素、H2O2和O2·-的共同调节。这些结果表明,镉胁迫下根系生长发育的变化是一个复杂的过程,与ROS、生长素和细胞周期都有密切联系。根系基因表达谱的变化,暗示在调节镉胁迫水稻根系生长发育过程中镉、生长素、H2O2和O2·-彼此之间存在交互作用。更多还原

【Abstract】 Changes of antioxidant enzymes in cadmium (Cd)-stressed transgenic rice (Oryza sativa L. cv. Zhonghua No.11) carrying glutathione-S-transferase (GST) and catalasel (CAT1) and non-transgenics roots and shoots were analyzed. Data showed that the activities of all antioxidant enzymes such as, CAT, GST, SOD, APX, DHAR and GR measured in the stressed transgenics roots and shoots were significantly different from those of non-transgenics. The mitigated oxidative damage induced by Cd in the transgenics resulted from the coordination of multi-antioxidant enzymes.The effect of IBA, H2O2 and O2-on root development in Cd-stressed rice (Oryza sativa L. cv. Zhonghua No.11) was analyzed. Results showed that the length of primary, adventitious and lateral roots as well as lateral root number is increased by single Cd, Cd supplemented with IBA or AT or DDC treatments, but reduced by Cd plus TIBA or DMTU or Tiron applications. A genome-wide expression analysis of OsPINs, OsPID, OsARFs, and cell cycle genes in difference-treated roots was conducted by using semi-quantitative reverse transcription-PCR. A total of 44,48,66 and 59 out of all 98 tested genes were regulated by Cd, H2O2, O2- and auxin, respectively. In these 98 genes, cadmium regulated 33 genes were also induced by H2O2; while 38 genes regulated by Cd were also induced by auxin; whereas 44 genes were regulated either by Cd or by O2-; there were 53 genes induced by both auxin and O2-; there were 36 genes regulated not only by Cd but also by auxin or O2-; and 29 genes were simultaneously regulated by Cd, auxin, H2O2 and O2-. Our data indicated that the regulation of root system in Cd-stressed rice is a complex process involving plant hormone, reactive oxygen species (ROS) and cell cycle. The altered gene expression profiles caused by Cd, H2O2,02- and auxin implied that a tight connection/crosstalk between Cd, axuin, ROS and cell cycle may be existence during regulation of Cd-stressed root growth.更多还原