Complete ammonia oxidation (comammox) bacteria can complete the whole nitrification process independently, which not only challenges the classical two-step nitrification theory but also updates long-held perspective of microbial ecological relationship in nitrification process. Although comammox bacteria have been found in many ecosystems in recent years, there is still a lack of research on the comammox process in rhizosphere of emergent macrophytes in lakeshore zone. Sediment samples were collected in this study from rhizosphere, far-rhizosphere, and non-rhizosphere of emergent macrophytes along the shore of Lake Liangzi, a shallow lake. The diversity of comammox bacteria and amoA gene abundance of comammox bacteria, ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) in these samples were measured. The results showed that comammox bacteria widely existed in the rhizosphere of emergent macrophytes and fell into clade A.1, clade A.2, and clade B, and clade A was the predominant community in all sampling sites. The abundance of comammox amoA gene (6.52 × 10⁶–2.45 × 10⁸ copies g⁻¹ dry sediment) was higher than that of AOB amoA gene (6.58 × 10⁴–3.58 × 10⁶ copies g⁻¹ dry sediment), and four orders of magnitude higher than that of AOA amoA gene (7.24 × 10²–6.89 × 10³ copies g⁻¹ dry sediment), suggesting that the rhizosphere of emergent macrophytes is more favorable for the growth of comammox bacteria than that of AOB and AOA. Our study indicated that the comammox bacteria may play important roles in ammonia-oxidizing processes in all different rhizosphere regions.

完全氨氧化（comammox）细菌可以独立完成整个硝化过程，这不仅挑战了经典的两步硝化理论，而且更新了长期以来对硝化过程中微生物生态关系的看法。尽管近年来在许多生态系统中发现了comammox细菌，但对湖滨区挺水植物根际comammox过程的研究仍然缺乏。本研究从浅湖梁子湖沿岸挺水植物的根际、远根际和非根际收集沉积物样品。测量了这些样品中comammox细菌的多样性以及comammox细菌、氨氧化古菌(AOA)和氨氧化细菌(AOB)的amoA基因丰度。结果表明，comammox细菌广泛存在于挺水植物根际，分为进化枝A.1、进化枝A.2和进化枝B，其中进化枝A是所有采样点的优势群落。comammox amoA基因（6.52 × 10 ⁶ –2.45 × 10 ⁸拷贝 g ⁻¹干沉积物）的丰度高于 AOB amoA基因（6.58 × 10 ⁴ –3.58 × 10 ⁶拷贝 g ⁻¹干沉积物），并且比AOA amoA基因（7.24×10 ² –6.89×10 ³拷贝g ^-1干沉积物）高4个数量级，表明挺水植物的根际比AOB和AOB更有利于comammox细菌的生长。迎角。我们的研究表明，comammox 细菌可能在所有不同根际区域的氨氧化过程中发挥重要作用。