【作者】 吴敏鸿；

【导师】 林文雄；

【作者基本信息】 福建农林大学 ， 生物化学与分子生物学， 2006， 硕士

【摘要】 植物化感作用(Allelopathy)是指一种活体植物(供体)产生并通过挥发(Volatilization)、淋溶(Leaching)、分泌(Exudates)和分解(Decomposition)等方式向环境释放某些化学物质而影响其他植物(受体)的生长和发育的化学生态学现象。近年来生态学和环境学也将其列为研究热点问题之一。 众多研究表明，在环境胁迫下大多数草本和木本植物的酚酸含量显著提高。鉴于植物体在释放化学物质中，供体根系与土壤，水分，受体植物如稗草等接触较为直接，其蛋白质变化更敏感，据此实验以供体水稻根系为主要研究对象。运用差异蛋白质组学和生物信息学研究手段，标记了非化感水稻和化感水稻对不同因子胁迫响应的分子机制。为将来水稻化感作用的分子生态学机理提供依据。 本实验利用两个N素处理水平即正常N水平(1N，20mg／L)和低N水平(1／4N，5mg／L)，和两个稗草处理密度，即有共培稗草(稻：草=35：5)和无稗草共培(稻：草=40：0)。在处理7天侯提取2个水平(1／4氮水平和1氮水平)，2个处理(有稗草共培和无稗草共培)的不同水稻的根系全蛋白对其进行2-DE电泳，经银染后进行蛋白质图谱分析，共发现1000-1200个蛋白质点。其中45个蛋白质在不同条件下表达有差异，通过MALDI-TOF／MS分析方法和数据库的检索，鉴定出其中43个蛋白。这些蛋白可分为4大类，它们参与了水稻抗性防卫、信号传导、碳氮代谢和蛋白质骨架形成。研究还发现化感水稻和非化感水稻根系蛋白构成几乎相同，在各自代谢中都存在着一个复杂的信号应答和代谢调控网络，并通过差异表达的蛋白质反映出各自生理生化的特征。分析结果发现化感水稻在逆境胁迫中抗性和防卫相关蛋白的表达丰度明显增强，这是化感水稻重要的分子生态学特性。 本研究中还发现了若干水稻抗性防卫相关蛋白，在进行鉴定和初步评价后，认为它们就是当前化感作用研究中的关键蛋白。据此，作者对这些关键蛋白进行3D结构预测和功能分析，为进一步分析克隆奠定了工作基础。文中还就存在的问题与主攻的方向做了较为深入的探讨。更多还原

【Abstract】 The allelopathy effect are due to inhibitory substances that are released directly or indirectly from living plants (donor) into the environment through root exudation, leaching, volatilization and residual decomposition of the donor plant. These phytotoxic substances are termed as allelochemicals. The partential of allelopathy has been a particularly intense study area of ecology and environment science.Numerous research indicated that the content of phenolic acid in the herbaceous and wood plants increased in the environment stress. Because when plant exudated chemicals to environment, root is more directly contact with soil, water and received plant such as barnyardgrass(BYG), the changes of root protein would be more sensitive. We regard rice root as a main research boject to discover the molecular mechanism responding to different stresses in allelopathic and nonallelopathic rice accessions by using differential proteomics and bioinformatics as a tool. The expriment composed of two N supplies (1N,20mg/L,1/4N, 5mg/L) and two desities of barnyardgrass (rice:BYG=35:5,rice:BYG=40:0). After treatment for 7 days, we extracted the protein in two treatments with two level. Then two-dimensional gel electrophoresis (2-DE) of the proteins was performed. Image analysis revealed about 1000-1200 protein spots on each 2-DE gel after stained with silver nitrate.It was found that 45 proteins expressed differentially in different treatments, forty-three proteins were identified by MALDI-TOF/MS and database searching. These proteins were divided into 4 catagories : defense, signal transduction, metabolism and protein stabilization. The composition of proteins in the two rice accessions PI312777 ( allelopathy) and Lemont (nonallelopathy) is almost the same, each of them has a complex resistant signal transduction and metabolic regulative network, and the physicochemical properties were charactierized by the proteins showing differential expression pattern. The abudance of resistent and defensive proteins increased significantly with the environment stress enhancing, which could be considered the properties of molecular ecology in allelopathic rice.Several resistent-related proteins were also found in this research, after evaluating, we considered they might be the key resistent proteins accomplished with allelopathy. Accordingly, 3D structure of the key proteins and its function were predicted and further analysed. The result would provide helpful information to our further research on molecular cloning. Finally,the existing problems and the direction to further study were discussed in the paper.更多还原