Recent advances in soil organic carbon (SOC) formation indicate that labile plant C is disproportionately important for stable SOC pool because it is utilized more efficiently by soil microbes. Rhizodeposited C, accounting for 5–20% of photosynthates, are highly bioavailable and readily metabolized substrates for soil microbes. However, it remains poorly understood how different microbial functional groups contribute to transforming rhizodeposited C to SOC. Here, we synthesized 23 studies performing ¹³CO₂ pulse labelling of plants in conjunction with stable isotope probing of microbial phospholipid fatty acids, and explored the fate of rhizodeposited C in different soil microbial functional groups. Among microbial groups, fungi (25.3%) and gram-negative bacteria (GN; 23.5%) took up most of the rhizodeposition-derived C, while the relative abundance of fungi (13.7%) was less than a half of GN (32.7%). These results suggest that fungi have a higher capability of acquiring rhizodeposition-derived C, which may be due to their hyphal growth form allowing them to obtain rhizodeposited C more effectively. The mean turnover rates of rhizodeposited C in microbial groups ranged from 0.04 to 0.13 day⁻¹. We did not detect significant differences in the turnover rates of rhizodeposited C among microbial groups. Based on the distribution and turnover rate of rhizodeposited C in different microbial groups, we further revealed that GN (31.2%) and fungi (25.8%) produced the most microbial residues via rhizodeposition-derived C. Our results provided quantitative information about the roles of different microbial functional groups in competing for and processing rhizodeposition-derived C, which could help refine parameter estimation in modeling microbial transformation of plant C into SOC under global changes.

土壤有机碳（SOC）形成的最新进展表明，不稳定的植物C对于稳定的SOC库至关重要，因为土壤微生物可以更有效地利用它。根状沉积的碳占光合产物的5–20％，具有很高的生物利用度，并且容易被土壤微生物代谢。但是，仍然缺乏了解如何将不同的微生物官能团有助于将根状沉积的C转化为SOC。在这里，我们合成了23个进行¹³ CO _2的研究脉冲标记植物，结合微生物磷脂脂肪酸的稳定同位素探测，并探索了根瘤菌沉积的C在不同土壤微生物功能组中的命运。在微生物组中，真菌（25.3％）和革兰氏阴性细菌（GN； 23.5％）占据了根茎沉积来源的大部分碳，而真菌的相对丰度（13.7％）不到GN（32.7％）的一半。 ）。这些结果表明真菌具有更高的获得根状沉积的C的能力，这可能是由于它们的菌丝生长形式使得它们能够更有效地获得根状沉积的C。微生物组中根状沉积碳的平均周转率介于0.04至0.13天^-1。我们没有发现微生物组之间根状沉积的C的周转率有显着差异。根据根际沉积的C在不同微生物组中的分布和周转率，我们进一步揭示了GN（31.2％）和真菌（25.8％）通过根际沉积的C产生了最多的微生物残留。竞争和加工根状沉积物衍生的碳中的不同微生物功能组，这有助于在全局变化下模拟植物C向SOC的微生物转化过程中优化参数估计。