基于label-free技术的青杨3个叶位叶片比较蛋白质组学分析
Label-free approach based comparative proteomics analyses of three leaf positions in Populus spp.(Sectiontacamahaca) 为了研究青杨不同叶位叶片蛋白质组的表达变化规律和青杨叶片衰老的蛋白质组学机制，采用非标记蛋白质组学（label-free）方法对杂交青杨子代3个叶位叶片蛋白质组变化进行了分析。结果表明:3个不同叶位叶片共检测到111个差异表达蛋白质,其中55%的差异蛋白质仅在25叶位与5叶位的比较中差异显著;差异表达蛋白质功能分析表明,青杨叶片成熟到衰老过程中与光合作用、生长发育相关蛋白在10和25叶位多呈现下调表达，逆境反应、营养分解转运相关蛋白在10和25叶位多上调表达，而一些转录翻译与修饰调控相关蛋白质则主要呈现波动趋势;青杨3个叶位中，10叶位光合作用和物质合成比5叶位活跃，25叶位叶片由于衰老营养物质分解转运加强，物质合成减弱。蛋白质是细胞功能执行者，可见，青杨叶片成熟到衰老是受蛋白质表达变化有序调控的过程。

In order to reveal rules of proteomic changes in different leaf positions of Populus spp.(Section tacamahaca) and senescence mechanism of the leaves,proteins expression profile at three leaf positions of Populus spp. (S. tacamahaca) hybrids were studied with label free proteomics.The proteins of three different leaf position were detected using label free method.111 proteins with differential expression were found,only 55% proteins expressed significantly differently in comparison with the 5th and 25th leaf position.Functional analysis of differentially expressed proteins showed that the proteins involved in photosynthesis,growth and development were mostly down regulated at 10th and 25th leaf position,while proteins involved in stress,nutrient decomposition and transport were mostly up regulated among the leaf senescence process.However,some proteins related to transcriptional,translation and protein modification regulation had fluctuations among the leaf senescence process.Among the three leaf positions of Populus spp.(S. tacamahaca),photosynthesis and nutrient synthesis process at 10th leaf position were more active than that at 5th leaf position.The 25th leaf leaves are enhanced by the decomposition and transport of aging nutrients,and the synthesis of the material is weakened.The decomposition and transport of senescence nutrient at 25th leaf position were enhanced and synthesis of nutrient was decreased.Protein is a cell function performer,which shows that the maturity of young leaves to senescence is a process of orderly regulating protein expression changes.