根系分泌物影响原位根际磷酸三(2-氯乙基)酯降解功能微生物群落的机制研究

土壤中的磷酸三(2-氯乙基)酯（TCEP）对生态环境和人体健康构成了严重威胁。根际环境，尤其是根系分泌活动，可以加速土壤微生物对TCEP的降解和转化，但其机理尚不清楚。本项目拟以黑麦草和紫花苜蓿为模型植物，通过比较TCEP在根际和非根际样品中降解过程的差异，揭示根际效应对TCEP降解效率及降解途径的影响；采用DNA-稳定性同位素探针技术对根际、非根际土壤进行标记，直接鉴定在原位环境中参与TCEP降解的功能微生物物种，结合宏基因组分析降解功能微生物基因组及降解基因特征，明确根际效应在功能微生物群落演化中的作用；借助傅里叶变换离子回旋共振质谱获得根系分泌物指纹图谱，解析不同根系分泌物与TCEP降解功能微生物群落、降解微生物基因之间的关系，揭示根系分泌物作用原理，阐明根际效应的潜在机制。本研究旨在探究根系分泌物在根际效应中的作用，为微生物根际调控提供理论依据，并服务于TCEP污染土壤修复。

Tris(2-chloroethyl) phosphate (TCEP) in soil threatens environment and human health heavily. Rhizosphere, especially the root exudates, can promote TCEP microbial degradation and transformation. However, its mechanism is still unknown. In the present study, the role of rhizosphere effects on the TCEP metabolizing will be elaborated by comparing the TCEP degradation kinetic characteristics in non-rhizosphere with rhizosphere samples. DNA stable isotope probing will be employed to directly link unknown functional microbes to TCEP degradation in the non-rhizosphere and ryegrass/alfalfa rhizosphere soils. With the aid of metagenome sequencing, the genomic information of TCEP degraders will be characterized and the degradation mechanism will be revealed. The composition of root exudates will be further resolved by Fourier transform ion cyclotron resonance mass spectrometer, and their roles on TCEP degraders’ community and genes will be disclosed, which is important for revealing the mechanism of rhizosphere effects. Our research will resolve the role of root exudates on rhizosphere effect, which is crucial for constructing the efficient plant-microbe system to enhance TCEP contamination remediation.