我国具有大面积的碳酸盐土地，筛选耐碳酸盐生物资源并探究其生存机制，对碳酸盐土地生物修复和作物改良具有重要意义。我们前期筛选得到了一种耐极端碳酸盐的小球藻JB6，其耐高浓度NaHCO3的能力是同属小球藻的20倍，电镜观察发现，JB6的细胞壁厚度和在高浓度NaHCO3胁迫中的稳定性远远超过同属对照小球藻。基于此，本项目拟利用电镜三维重构和GC-MS/MS等技术，解析JB6细胞壁的三维结构和鉴定细胞壁的组成成分以及其在NaHCO3胁迫下的变化，以揭示JB6细胞壁特殊的结构和成分；通过酶解细胞壁相应成分和构建细胞壁关键基因敲除突变体和过表达突变体，并进行碳酸盐耐受性实验，明确JB6细胞壁与JB6适应极端碳酸盐胁迫能力的关系。以上结果将为进一步揭示JB6在碳酸盐胁迫中的生存机制提供新的科学依据。

There is a large-scale carbonate soil in China. Screening carbonate-tolerant biological resources and exploring their survival mechanism are of great significance for the biological restoration of carbonate soil and crop cultivation. Our previous studies have characterized one high concentrations of NaHCO3-tolerant Chlorella JB6, which is 20 times more tolerant to NaHCO3 than the reference Chlorella from the same genus. TEM revealed that the thickness and stability of JB6 cell wall under NaHCO3 stress far exceed that of the reference Chlorella. In this project, we intend to use three-dimensional reconstruction technologies and GC-MS/MS to reveal the three-dimensional architecture and composition of JB6 cell wall, as well as the changes of cell wall under NaHCO3 stress. Additionally, the relationship between JB6 cell wall and tolerance of JB6 to extreme carbonate stress will be determined by tolerance analysis of cells after enzymatic hydrolysis of cell wall corresponding components and knockout /overexpression mutants of key cell wall genes. These results would provide new insights for further understanding the survival mechanism of JB6 under NaHCO3 stress.