单细胞水平解析土壤固氮鱼腥藻的碳氮固存过程研究进展

固氮鱼腥藻作为光能自养型微生物，具备良好的碳氮固存能力。施加固氮鱼腥藻能够提升土壤肥力并减少化肥施用量。然而，解析固氮鱼腥藻在土壤中的碳氮固存机制以及不同菌株固存效率差异仍有待深入研究。因此，从单细胞水平对土壤固氮鱼腥藻菌株进行筛选和碳氮固存过程的研究至关重要。针对固氮鱼腥藻在单细胞水平上发生的复杂而动态的元素变化过程，本研究综述了土壤固氮鱼腥藻碳氮固存过程，并探讨了利用纳米二次离子质谱法与稳定同位素标记结合(nano-secondary ion mass spectrometry-stable isotopic probing, NanoSIMS-SIP)技术和拉曼光谱成像与稳定同位素标记结合(Raman spectroscopy imaging-stable isotopic probing, Raman-SIP)技术解析单细胞水平上的碳氮元素的时空分布的原理、进展与难点。重点关注了单细胞稳定同位素技术定量可视化固氮鱼腥藻碳氮固存的最新技术发展与应用。同时，对该类可视化技术的未来研究进行了展望。本研究对于理解固氮鱼腥藻在土壤中的碳氮固存机制和固氮效率差异具有重要的科学意义，为农业生产中减少化肥使用、提高土壤肥力提供理论依据。

Research progress in the mechanisms of carbon and nitrogen sequestration by Anabaena azotica in soil at the single-cell level

Anabaena azotica, as a photoautotrophic microorganism, has good carbon and nitrogen sequestration abilities. The application of A. azotica could improve soil fertility and reduce the application of chemical fertilizers. However, the mechanism of carbon and nitrogen sequestration in soil by A. azotica and the sequestration efficiency of different strains remain to be studied. Therefore, it is important to screen A. azotica strains and probe into the processes of C and N sequestration in soil by the strains at the single-cell level. In view of the complex and dynamic process of element changes in A. azotica at the single-cell level, this study introduced the carbon and nitrogen sequestration process in soil by A. azotica. In addition, we expounded the principle, progress, and difficulties of using nano-secondary ion mass spectrometry combined with stable isotopic probing (NanoSIMS-SIP) and Raman spectroscopy imaging combined with stable isotopic probing (Raman-SIP) to analyze the spatiotemporal distribution of carbon and nitrogen at the single-cell level. This review focuses on the latest technological development and application of single-cell stable isotope technology for quantitative visualization of carbon and nitrogen sequestration in A. azotica. At the same time, future research on the visualization technology is prospected. This review is of great scientific significance for understanding the mechanism of carbon and nitrogen sequestration and the difference in nitrogen fixation efficiency of different A. azotica strains in soil. It provides a theoretical basis for reducing the use of chemical fertilizers and improving soil fertility in agricultural production.