高钙逆境中植物根际微生物与内生菌的生理功能和生态作用研究

Excessive soil calcium content seriously affects the growth of vegetation in karst area. Studies have shown that rhizosphere microorganisms and endophytes can help host plants adapt to salt and drought and other adverse environments. This provides the basis for studying the function of rhizosphere microorganisms and endophytes in the karst high calcium ecosystem. Our preliminary study found that the roots and leaves of Cochlearia henryi commonly seen in karst area wre highly enriched with specific flora, and the multiple operational taxonomic units (OTUs) shared by Cochlearia henryi rhizosphere, roots and leaves were closely related to known resistant strains, so we speculated that Cochlearia henryi rhizosphere and endophytic strains promoted Cochlearia henryi's adaptility to high calcium stress. In this project,we plan to isolate the Cochlearia henryi rhizosphere and endophytic microorganisms, and then inoculate highly sterilized Cochlearia henryi and Arabidopsis thaliana. Plants will be cultivated in high calcium environment. The effects of the infection on the physiological indexes of the plants will be analyzed. The gene expression alternations caused by inoculation will also be detected, so as to analyze the molecular mechanism underlying the physiological function of the strains. The ability of the strain to help the host adapt to the karst ecological environment will be tested by field experiment. The study will reveal the functions of rhizosphere and endophytic microorganisms in high calcium ecosystem, and lay the foundation for the development of microbial agents suitable for high calcium soils.

土壤钙含量过高严重影响喀斯特地区植被的生长。已有研究证明, 根际微生物和内生菌可帮助宿主植物适应盐、旱等多种逆境。这为研究喀斯特高钙逆境中适生植物的根际微生物和内生菌的功能提供了依据。我们的前期工作发现：高钙逆境中常见植物柔毛岩芥的根部和叶片有选择性的富集特定菌群，而且根际、根部和叶片共有的多个 operational taxonomic units (OTUs) 与已知抗逆菌种有很近的亲缘关系，由此推测根际和内生菌与柔毛岩芥适应高钙逆境有关。本项目拟分离柔毛岩芥根际和内生菌株，接种经深层灭菌的柔毛岩芥和模式植物拟南芥，模拟高钙环境培养；检测菌株侵染对宿主生理指标的影响，分析菌株的生理功能；检测宿主的基因表达变化，分析菌株生理功能的分子机理；通过野外栽培实验，检测菌株帮助宿主适应喀斯特生态环境的能力。该研究将揭示高钙逆境中植物根际和内生菌的功能，并为开发适合高钙土壤的微生物菌剂奠定基础。

土壤钙含量过高严重影响喀斯特地区植被生长，是该地区生态环境保护和农业发展的主要限制因素。根系微生物是植物逆境适应性的关键影响因素。本项目的前期工作发现：高钙逆境中常见植物柔毛岩芥的根部和叶片有选择性的富集特定菌群，而且其核心菌株与已知抗逆菌种有很近的亲缘关系。我们由此推测柔毛岩芥根系微生物与喀斯特高钙逆境适应性有关。本项目分离、纯化柔毛岩芥根系微生物并分析其功能，获得了可以提高拟南芥高钙逆境抗性的细菌菌株；该菌株可以改善高钙胁迫下拟南芥根部生长，帮助维持拟南芥根部钠钾离子平衡；转录组分析表明，拟南芥钙代谢相关基因受到了益生菌的调控，在益生菌提高拟南芥高钙逆境抗性过程中起关键作用。全长转录组测序结果表明，lncRNA-miRNA-mRNA调控网络，也在这一过程中起重要作用，并鉴定了关键的lncRNA分子及其调控miRNA和mRNA。本研究揭示了高钙逆境中植物根系微生物的功能，获得可提高植物高钙逆境抗性的菌株，并为开发适合高钙土壤的微生物菌剂奠定基础。