根际环境对超累积植物东南景天内生细菌的多样性和定殖的影响

项目名称： 根际环境对超累积植物东南景天内生细菌的多样性和定殖的影响

项目编号： No.41471264

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 地质学

项目作者： 龙新宪

作者单位： 华南农业大学

项目金额： 89万元

中文摘要： 在长期的选择和进化过程中，内生细菌与宿主植物形成一种和谐联合的关系，共同抵抗不利环境条件。当土壤重金属浓度增加时，超积累植物是否会选择性让土壤中某些金属抗性和（或）促植物生长细菌进入体内，或植物体内原有的内生菌大量增殖，进而协同超积累植物完成对重金属吸收、积累、解毒过程呢？本项目以典型的锌镉超积累植物东南景天为研究对象，通过培养方法和非培养方法（PCR-DGGE和高通量测序）分析其体内内生菌多样性及其随土壤环境条件变化；采用pDSK-GFPuv基因标记技术、荧光显微镜技术和共聚焦激光扫描显微镜技术跟踪特定内生菌对东南景天的侵染、定殖和分布特征，深入认识东南景天与内生细菌在超积累重金属过程中的相互关系，从植物与内生细菌相互作用的角度来补充解释东南景天对锌、镉的吸收、积累及解毒的生理生态机制。

中文关键词： 重金属；超累积植物；植物修复；修复机理；生态毒理

英文摘要： The characteristics of endophytic bacterial diversity and distribution are conditioned by biotic and abiotic factors. Under heavy pollution environment, plants might select endophytic bacteria which can assist their host plants in overcoming phytotoxic effects and promoting plant growth. Our previous study proved that the ability of uptake and accumulation of Zn/Cd differed significantly between hyperaccumulator ecotype and non-hyperaccumulator ecotype of Sedum alfredii. Furthermore, the cultureable endophytic bacteria number and community structure were affected by soil environment. However, we know little about the biodiversity, infection and colonization of endophytic bacteria in hyperaccumulator plant S. alfredii. In this study, the differences of genetic diversity and community of endophytic bacteria between hyperaccumulator ecotype and non-hyperaccumulator ecotype of S. alfredii were assessed using a combination of dilution plating of plant macerates followed by isolation and characterization of isolates and the restriction enzyme 16S fragment rDNA polymorphism (16SrDNA-RFLP), denaturing gradient gel electrophoresis (DGGE)and 454 pyrosequencing on the basis of DNA extracted from plants. The influence of soil environment, soil Zn and Cd pollution level and endophytic bacteria of seedling on the community structures and biological roles of endophytic bacterial in the root, stem and leaf tissues of two ecotypes of S. alfredii at different growth and development stage were also investigated. Colonization dynamics of plant growth promoting endopytic bacteria Pseudomonas fluorescens labeled with GFP (pDSK-GFPuv) in rhizosphere soils and the root, stem and lef tissues of S. alfredii plants were investigated by the use of GFP-tagged strains in combination with spread plate method，fluorescence microscopy and confocal laser scanning microscopy (CLSM). The results will reveal the endophyte communities of S. alfredii , clarify the relationships among S. alfredii, soil environment and the endophytic bacterial diversity and community structures and discover new endophytic bacteria resouces, in order to lay a good scientific foundation for developing technogy of endophytic bacteria assisting phytoremediation of heavy metal contaminated soils.

英文关键词： heavy metal;hyperaccumulator;phytoremediation;mechanism of phytoremediation;ecotoxicolog