Molecular and physiological basis of Rubisco turnover and its relation to nitrogen nutrition

Rubisco转换的分子和生理基础及其与氮营养的关系

基本信息

批准号：
15380046
负责人：
MAE Tadahiko
金额：
$ 10.11万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2006
项目状态：
已结题

项目摘要

Effects of nitrogen nutrition on the relationships between the levels of rbcS and rbcL mRNAs and the amount of Rubisco synthesized in rice leaves from emergence through senescence.The levels of rbcS and rbcL mRNAs, the amount of Rubisco synthesized, and the N influx greater for the 4 mM treatment than for the 1 mM treatment throughout the experiment. The mount of Rubisco synthesized was well correlated with the levels of both mRNAs during leaf expansion, but not after the completion of leaf expansion in both N treatments. The ratio of the amount of Rubisco synthesized to the levels of both mRNAs dramatically declined after full expansion. On the other hand, the amount of Rubisco synthesized was well correlated with the N influx in both N treatments. These results indicate that the N influx, namely, N availability, rather than the levels of rbcS and rbcL mRNAs, is more closely related to the amount of Rubisco synthesized in the leaf blade of rice throughout the life span of a leaf.Exclu … More sion of Rubisco from chloroplasts by specific bodies in naturally senescing leaves of wheatImmunocytochemical electron-microscopic observation indicated that Rubisco and/or its degradation products are localized in small spherical bodies having a diameter of 0.4-1.2 μm in naturally senescing leaves of wheat. These Rubisco containing bodies (RCBS) were found in the cytoplasm and in the vacuoles,. RCBs contained another stromal protein, chloroplastic glutamine synthetase, but not thylaloid proteins. Ultrastructural analysis suggested that RCBs had double membranes, which seemed to be derived from the chloroplast envelop, and that RCBS were further surrounded by the other membrane structures in the cytoplasm. The appearance of RCBs was the most remarkable when the amount of Rubisco started to decrease at the early phase of leaf senescence. These results suggest that RCBS might be involved in the degradation process of Rubisco out side of chloroplasts during leaf senescence.In vivo frgmentation of the large subunit of Rubisco by reactive oxygen species in an intact leaf of Cucumber under chilling conditions.When lea discs of chilling-sensitive cucumber were illuminated at 4-℃, five major fragments of the LSU were observed. This fragmentation was completely inhibited by ROS scavengers and Tiron stimulated this fragmentation, whereas an iron-specific chelator, deforoxamine, suppressed it. Further, such fragments were identical to those generated from the purified Rubisco by an-OH-generating system in vitro on two-dimensional PAGE. These results indicate that the direct fragmentation of Rubisco by reactive oxygen species also occurs in an intact leaf. Less

氮素营养对水稻出苗至衰老叶片rbcS和rbcL mRNA水平与Rubisco合成量关系的影响。rbcS和rbcL mRNA水平、Rubisco合成量以及氮流入量越大在整个实验过程中，4 mM 处理与 1 mM 处理相比，合成的 Rubisco 量与叶展开过程中两种 mRNA 的水平密切相关，但在叶完成后则不然。两种 N 处理中的 Rubisco 合成量与两种 mRNA 水平的比率在完全扩张后急剧下降。表明氮流入，即氮利用率，而不是 rbcS 和 rbcL mRNA 的水平，与水稻叶片在整个叶子生命周期中合成的 Rubisco 量更密切相关。排除 … 更多小麦自然衰老叶片中特定体从叶绿体中分离Rubisco免疫细胞化学电子显微镜观察表明，Rubisco和/或其自然降解产物位于这些小麦衰老叶片中直径为0.4-1.2μm的小球体中。在细胞质和液泡中发现了含有体（RCBS），RCB 含有另一种基质蛋白，叶绿体谷氨酰胺。超微结构分析表明，RCB 具有双层膜，似乎源自叶绿体包膜，并且 RCBS 进一步被细胞质中的其他膜结构包围。 Rubisco 的量在叶片衰老早期开始减少，这些结果表明 RCBS 可能参与了叶片叶绿体外 Rubisco 的降解过程。在寒冷条件下，黄瓜完整叶片中的活性氧对 Rubisco 大亚基进行体内断裂。当对寒冷敏感的黄瓜的 lea 盘在 4℃ 下照射时，观察到了 LSU 的 5 个主要片段。 ROS 清除剂完全抑制了碎片化，Tiron 刺激了这种碎片化，而铁特异性螯合剂去福罗沙明则抑制了这种碎片化。此外，这些碎片与生成的碎片相同。这些结果表明，活性氧对 Rubisco 的直接裂解也发生在完整的叶子中。