Latitudinal patterns and phosphorus-driven regulation of abundant and rare fungal communities in coastal wetlands

Fungal community typically consist of a few abundant and numerous rare taxa, both of which are crucial for supporting plant growth and maintaining ecosystem functions in coastal wetlands. However, the biogeographic patterns and the ecological drivers of abundant and rare fungi remain elusive, hampering our understanding of their functional roles in these ecosystems. Here, we studied the latitudinal patterns of abundant and rare fungi and their determinants via a large-scale investigation (over 2500 km) in coastal wetlands across eastern China. Abundant and rare fungi exhibited distinct latitudinal patterns. The relative abundance of abundant fungi increased with increasing latitude, whereas the diversity and relative abundance of rare fungi decreased with increasing latitude. Multiple regression models revealed that spatial factor (latitude) predominantly determined the variation of both subcommunities; soil traits had a greater influence on abundant fungi, whereas plant traits were more influential on rare fungi. After accounting for the spatial and climatic factors in the structural equation models, our results further showed that soil C:P, N:P drive abundant fungi, while root N:P drive rare fungi. Taken together, our study revealed the differentiated responses of abundant and rare fungi to soil and root P, highlighting the importance of plant-fungi interactions on biogeographic pattern of soil fungi in coastal wetland ecosystems.