Microbial Turnover of Photosynthetic Carbon in the Rhizosphere and SIP Technology-A Review

As a major source of soil organic carbon, photosynthetic carbon is an important component in the carbon cycle in the atmosphere-plant-soil system. Soil microorganisms are essential in the turnover of photosynthetic carbon in the rhizosphere. Stable isotope probing(SIP), an isotope labeling technology combined with molecular biological approach, can be used to identify the structure of microbial communities and their functions in organic C turnover, and to examine functional linkages among microbes in biogeochemical processes in various environmental systems. The SIP technology exhibits great potential for wide applications in relevant areas in the future, since it can provide more accurate information on microbial interactions and metabolic functions in communities. In this paper, the allocation of photosynthetic carbon of crops below ground during growth period, and the relationship between root exudates and microorganisms were reviewed. The advantages and disadvantages of PLFA-SIP, RNA-SIP, and DNA-SIP in the study of microorganisms associated with carbon conversion were discussed. We proposed that the combination of these technologies would be useful in future studies on microbial ecology.