Despite the advantages of the next generation sequencing (NGS) techniques, one of their caveats is that they do not differentiate between microbes that are actively participating in carbon cycling in the rhizosphere and microbes performing other functions in the soils. Here we combined DNA-SIP with NGS to investigate which rhizosphere fungi actively assimilate plant-derived carbon. We provided ¹³CO₂ to plants in intact soil cores collected from a grassland and sampled the rhizosphere in a time series to follow the fate of carbon in the rhizosphere mycobiome. We detected a difference between active rhizosphere fungi using plant-derived carbon and the total mycobiota: 58% of fungal species were using fresh rhizodeposits, and an additional 22% of fungal species received carbon several weeks later while 20% were not involved in cycling of freshly photosynthesized carbon. We show that members of Ascomycota, Mucoromycota, and basidiomycete yeasts were first users of freshly photosynthesized carbon, while fungi not using recently fixed carbon consisted mainly of mycelial (non-yeast) Basidiomycota. We conclude that a majority of fungi inhabiting the rhizosphere in this grassland ecosystem are actively using plant derived carbon either directly or via food-web interactions.

尽管下一代测序（NGS）技术具有优势，但它们的告诫之一是它们无法区分在根际中积极参与碳循环的微生物和在土壤中发挥其他功能的微生物。在这里，我们将DNA-SIP与NGS结合使用，以研究哪种根际真菌能有效吸收植物来源的碳。我们提供了¹³ CO ₂采集从草地收集的完整土壤核心中的植物，并按时间序列对根际取样，以追踪根际菌群中碳的命运。我们检测到使用植物来源的碳的活性根际真菌与总真菌菌群之间的差异：58％的真菌物种使用新鲜的根茎沉积菌，另外22％的真菌物种在几周后获得碳，而20％的真菌不参与循环新鲜光合作用的碳。我们显示，子囊菌，毛霉菌和担子菌的成员是新鲜光合作用碳的首次使用者，而未使用最近固定碳的真菌主要由菌丝体（非酵母）担子菌组成。