Analysis of the Redox Regulation System and its Application of Molecular breeding in Higher Plants

1)光合作用电子传递的H_2O_2积累和氧化还原状态对细胞质抗坏血酸过氧化物酶(CapX)表达的影响。以叶绿体中表达过氧化氢酶和类囊体膜结合APX的转基因烟草为材料，研究了光氧化胁迫条件下PET氧化还原状态的变化和过氧化氢积累与CapX诱导的关系。这些结果表明，在衰老过程中，叶片氧化应激耐受能力下降的机制是不同年龄段叶片中各种抗氧化剂和抗氧化酶水平的差异。结果表明，在衰老过程中，抗氧化剂和抗氧化剂EN…水平的下降可能是由PQ库的氧化还原作用引起的2)AOS信号分子在调节包括环境胁迫反应在内的许多生理过程中的作用。我们以两个经-2转化的烟草细胞系CapX-S2和CapX-S3为材料，研究了转基因烟草BY-2细胞中CapX活性降低的影响。有趣的是，APX抑制的细胞对高温和盐度等环境压力表现出不同的反应和耐受性。抑制消减杂交显示，在CapX-S3细胞中有几个热和盐胁迫诱导基因的表达上调。3)转基因植物的分子育种。为了鉴定高等植物中与氧化还原调控相关的基因，我们试图获得表达氧化还原调控因子的转基因植株。较少

1)The influence of H_2O_2 accumulation and redox status of the photosynthetic electron transport on the expression of cytosolic ascorbate peroxidase (cAPX).Transgenic tobacco plants expressing catalase and thylakoid-membrane bound APX in chloroplasts, both of which had increased tolerance to photooxidative stress, were utilized for evaluation of the relationship between H_2O_2 accumulation or change of redox status of the PET and cAPX induction under photooxidative stress condition. These results suggest that the induction of cAPX expression is caused by a redox change in the PET, probable PQ pool at an early stage and-thereafter by an increase in the cellular H_2O_2 level.Next, to clarify the mechanism of the decline in oxidative stress tolerance of leaves during the course of senescence, we studied the differences in the levels of various antioxidants and antioxidant enzymes in leaves of different ages.The data suggest that the decline in the levels of antioxidants and antioxidant en … More zymes associated with leaf senescence lead to lower photooxidative-stress tolerance, which might in turn accelerate the propagation of senescence.2)The effect of AOS, signal molecules on the regulation of many physiological processes, including environmental stress responses.We investigated the effect of lowered cAPX activity in transgenic tobacco BY-2 cells, using two transformed BY-2 cell lines, cAPX-S2 and cAPX-S3. Interestingly, the APX-suppressed cells showed different responses and tolerances to environmental stresses, such as heat and salinity. Suppression subtractive hybridization revealed that several heat and salt-stress inducible genes were upregulated in cAPX-S3 cells. HSP70, DnaJ-like protein and purple acid phosphatase were among the constitutively induced genes.3)Molecular breeding of transgenic plants introducing the genes involved in the redox regulation.To identify the genes involved in the the redox regulation in higher plants, we are trying to generate transgenic plants expressing a redox regulatory factor. Less