高磷设施菜地土壤微生物群落结构及活性表达的分子生物学特征

The greenhouse vegetable field is a special ecosystem with characteristics of heavy anthropogenic disturbance and excess phosphorus (P) accumulation in soil. Thus soil microbial community structure and activity expression must have its special features which are quietly different from other natural ecosystems. We will firstly investigate the characteristics of soil microbial diversity and its relationship to soil properties under different level of P enrichment greenhouse vegetable soil through filed sampling and lab experiment. Then advanced metagenomics and metatranscriptomics tools of Illumina sequencing are adopted to illuminate the characteristics of soil microbial community structure and function of greenhouse vegetable field. The activity express of soil microbial community will preliminarily understand by meta-metabolomics. We try to reveal the specificity of soil microbial community structure and activity and its relationship to soil P status by the analysis of bioinformatics and statistics, coupling the dynamics of soil organic carbon mineralization and P fractions and so on. In this study, the method of system biology will be applied into greenhouse vegetable ecosystem for the first time, which will facilitate to comprehensively reveal the characteristics of the composition and function of soil microbial community in this ecosystem. The results in this project will improve the nutrient cycle theory of agricultural ecosystem, and also offer the important scientific basis for the sustainable development of facility agriculture.

设施菜地土壤是受人为干扰严重、土壤磷素高度富集的特殊生态系统，其微生物群落结构及活性表达必然有不同于自然生态系统的特殊性。本项目以设施菜地为研究对象，以磷素高度富集为切入点，采用野外采样与室内模拟相结合的方法，通过不同磷素水平对比研究高磷设施土壤微生物多样性特征及其与土壤性质的关系；通过宏基因组学和宏转录组学技术研究土壤微生物群落结构与功能特征，在此基础上尝试用宏代谢组学方法初步了解土壤微生物群落的代谢活性表达；通过生物信息学和统计学分析，耦合土壤有机碳矿化动态、磷素组分等指标，揭示高磷设施菜地土壤微生物群落结构及代谢活性的特异性及其与磷素之间的关系。本项目首次将系统生物学的方法应用于设施菜地，有助于全面深入地揭示设施菜地生态系统中土壤微生物群落组成及其功能特征，研究结果将完善农业生态系统中养分循环理论，为设施农业的可持续发展提供重要科学依据。

设施菜地土壤是受人为干扰严重、土壤磷素高度富集的特殊生态系统，其微生物群落结构及活性表达必然有不同于自然生态系统的特殊性。本项目以设施菜地为研究对象，监测了高磷设施土壤微生物多样性特征及其与土壤性质的关系；研究了设施土壤有机碳组分与磷组分的相互作用，通过酶学、宏基因组学和碳代谢指纹等技术在室内模拟条件下研究磷影响秸秆分解的微生物学机制，揭示了高磷设施菜地土壤微生物群落结构及代谢活性的特异性及其与磷素之间的关系。结果表明：土壤有效磷（AP）是引起群落发生改变的最主要因子，高磷土壤微生物多样性显著降低。小麦秸秆降解过程中随着有效磷增加及培养时间的延长，土壤CO2释放速率、微生物量碳氮均在第5天时达最大值。土壤磷水平增加可显著提高秸秆分解过程中细菌的AWCD值，在秸秆分解过程中微生物优先利用糖类作为碳源，之后利用羧酸类、氨基酸类碳源。添加秸秆和土壤磷水平提高均可显著提高土壤细菌和真菌的碳代谢功能多样性。基于宏基因组学方法研究发现，随着磷增加，参与碳代谢的相关酶活性显著增高，并于 20天时酶活性达峰值，此时功能基因丰度也显著提高。参与秸秆降解的微生物主要是细菌，尤其是在前期，中后期真菌的参与增加。土壤酶活性、微生物群落组成、功能基因丰度等随土壤磷水平的提高、秸秆的施用而发生明显改变。该研究结果有助于揭示设施菜地生态系统中土壤微生物群落结构特征，深刻理解不同土壤磷水平下秸秆降解过的程微生物学机制，对调控设土壤肥力水平、维持农业的可持续发展和改善生态环境均具有重要的理论和实践意义。