深色有隔内生真菌(DSE)增强玉米重金属耐性机制研究

深色有隔内生真菌（DSE）普遍定殖于重金属胁迫生境中植物的根内，然而其与宿主植物的生态学关系尚无明确定论；特定DSE菌株接种玉米后能增强玉米的重金属耐性，但其作用机制也不清楚。本研究拟在镉（Cd）胁迫下，给玉米接种DSE，利用数字基因表达谱（DGE）分析技术，明确Cd和DSE诱导玉米重金属耐性相关基因，并对耐性基因的表达模式和所涉及的代谢途径进行生物信息学分析；利用荧光定量PCR技术研究不同Cd浓度和接种DSE对玉米重金属耐性基因表达的影响；利用电子显微镜-Ｘ射线能谱仪和原子吸收光谱仪对DSE影响Cd在培养基质、DSE和玉米不同器官中的存在形式和富积量进行亚细胞定位、定量分析；检测在Cd胁迫下玉米抗氧化系统对接种DSE的生理学应答；从分子、细胞和生理学水平阐明DSE增强宿主植物重金属耐性机制，为理解DSE与宿植物的生态学关系和将DSE应用于农田重金属污染土壤修复提供科学依据。

Dark septate endophytes (DSE) are ubiquitously colonizing in the plant roots growing in heavy metal (HM) stressed environments. While the ecological relationships between DSE and their host plants are not clear. Our previous studies have found that a DSE strain comes from HM mining area can enhance maize of HM tolerance when it colonized in maize roots, but it's mechanism is also not clear. In the presenting project, we want to identify HM tolerance related genes of maize induced by　cadmium (Cd) and DSE under Cd stressed condition using digital gene expression profile (DGE) analysis. The expression patterns and metabolic pathways involved of these genes will be analyzed by bioinformatic techniques.The influences of differnet concentrations of Cd and DSE innoculation time on the expression of these maize HM tolerant genes will also be detected by RT-PCR.The impacts of DSE on the chemical forms of Cd in the cultivation matrix,extraradical mycelia of DSE,different organs of maize,and their subcellular localization and accumulation will be analyzed by SEM-EDS (scanning electronic microscope-energy disperive X-ray spectrometer) and atomic adsorption spectrometer(AAS). The antioxidant system responses of maize to the inoculation of DSE under Cd stressed condition will be detected. The aims of the presenting project are to document the mechanisms of HM tolerance of maize enhanced by DSE from molecular, cellular and physiological progresses,to provide a scientific basis for explaining the ecological relationships between DSE and their host plants, and the application of DSE in the remediation of HM polluted farmland soil.