烟草叶片衰老期过程中的蛋白质组学分析

大田烟叶生产过程中因打顶打叉的处理，改变了烟叶正常的衰老模式。为研究这一特殊的衰老机制，我们自旺长期开始，对‘云烟87’不同发育阶段烟株的中部叶片，进行形态观测、生理生化分析及蛋白质组学检测。结果显示：随着烟叶的逐渐成熟和衰老，烟草的叶色逐渐变黄，叶片逐渐变短、变窄，厚度减少；解剖结构清晰看到栅栏组织和海绵组织从最初的整齐排列到逐渐排列紊乱，组织细胞间轮廓不明显，细胞间隙明显增大；亚显微观测表明，淀粉粒在叶绿体中逐渐积累，类囊体片层结构被挤散，叶绿体膜被撑破。生理与生化分析表明衰老过程伴随着光合作用速率下降，光合色素降解加速，呼吸代谢的增加，这可能与衰老叶片中叶绿体逐渐崩塌和细胞膜透性增加相一致。iTRAQ标记方法共检测到不同发育阶段432个差异表达蛋白质，其中注释到308个与多种生命过程相关。蛋白差异富集分析表明，烟草叶片衰老过程中与光合作用等合成代谢相关蛋白多下调表达，而逆境反应及呼吸作用等分解代谢相关蛋白多上调表达。

Proteomic Analysis of Senescing Leaf of Tobacco

During period of tobacco field cultivation, the topping procedure changes normal aging mode of to- bacco leaf into special senescing process. For the research of this particular aging mechanism of tobacco leaf, the middle part leaves of ＇Yunyan87＇ from prosperous phase to post matured stage were used to analyze the changes of morphology, metabolism and proteome. The results showed that leaves gradually turn yellow with slightly reducing size in length, width and thickness during the maturing; anatomical structures of both palisade and spongy tissue of leaves changed from the neatly arranged to progressively disorganized with significantly increased cell gap; electric microscopically observation showed that the gradual accumulation of starch grains in chloroplast, crowded the thylakoid lead to bursting of membrane of chloroplast. The rate of photosynthesis was reduced with the aging process, companying with the degradation of photosynthetic pigments due to chlo- roplasts collapse, while rate of respiration is increased due to permeability increasing of cell membrane. The total 432 differentially expressed proteins form different developmental stages leaves were detected with iTRAQ labeling, among which 308 were annotated to associate with a various metabolic pathways. Analysis of differential expressed proteins shown that proteins related to anabolic process, such as photosynthesis are down regulated; while the ones related to stress response and catabolism such as respiratory metabolism, are up regulated.