Ng Ming Sheng, Soon Nathaniel, Chin Min Yi, Ho Sze Koy, Drescher Lynn, Sani Mohamad Azlin Bin, Lim Kiah Eng, Wainwright Benjamin J, Chang Ying
Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore, 117558, Singapore.
Yale-NUS College, National University of Singapore, 16 College Avenue West, Singapore, 138527, Singapore.
Environ Microbiome. 2025 Mar 25;20(1):34. doi: 10.1186/s40793-025-00686-6.
Microbial communities in mangrove sediments play vital ecological roles that underpin the functioning of the overall mangrove ecosystem. Fungal communities, in particular, are known to play crucial roles across sediment systems, yet their roles in mangrove sediments, especially in deeper layers, remain poorly understood without a comprehensive inter-domain characterization. To better understand fungal roles in sediment horizons, 10 sediment cores extending down to a depth of 1 m were taken in three mangrove sites to characterise the archaeal, bacterial, and fungal communities at 10 cm depth intervals.
We demonstrate that sediment depth has distinct effects on the three microbial communities. While fungal community compositions were similar across sediment depths, bacterial and archaeal community compositions were stratified into three distinct layers, surface (10-30 cm), subsurface (40-60 cm), and deep (70-100 cm). Co-occurrence networks were then constructed to investigate the roles of fungi in these sediment layers, where fungi were consistently identified as keystone taxa in maintaining the microbial network topology, with co-domain interactions constituting more than half of all interactions. Even in the deepest layer, fungal nodes still retained high betweenness centralities, acting as network hubs to potentially augment microbial interactions vital for the functioning of the overall ecosystem.
Overall, our results emphasise the important role of fungi in mediating microbial interactions across sediment depths even in deep, anoxic sediment layers, and highlight the importance of cross-domain interactions as integral to a more holistic understanding of the mangrove microbiome.
红树林沉积物中的微生物群落发挥着至关重要的生态作用，是整个红树林生态系统功能的基础。特别是真菌群落，已知在整个沉积物系统中发挥着关键作用，然而，在缺乏全面的跨域特征描述的情况下，它们在红树林沉积物中的作用，尤其是在较深层中的作用，仍知之甚少。为了更好地了解真菌在沉积物层中的作用，在三个红树林地点采集了10个深度达1米的沉积物岩芯，以每隔10厘米的深度间隔对古菌、细菌和真菌群落进行特征描述。
我们证明沉积物深度对这三个微生物群落有明显影响。虽然真菌群落组成在不同沉积物深度相似，但细菌和古菌群落组成被分层为三个不同的层，即表层（10 - 30厘米）、次表层（40 - 60厘米）和深层（70 - 100厘米）。然后构建共现网络来研究真菌在这些沉积物层中的作用，其中真菌一直被确定为维持微生物网络拓扑结构的关键类群，跨域相互作用占所有相互作用的一半以上。即使在最深层，真菌节点仍保持较高的介数中心性，充当网络枢纽，可能增强对整个生态系统功能至关重要的微生物相互作用。
总体而言，我们的结果强调了真菌在介导不同沉积物深度的微生物相互作用中的重要作用，即使在深层缺氧沉积物层中也是如此，并突出了跨域相互作用对于更全面理解红树林微生物组的重要性。
