Distribution, assembly, and interactions of soil microorganisms in the bright coniferous forest area of China's cold temperate zone

Spatiotemporal patterns of soil myxomycetes in subtropical managed forests and their potential interactions with bacteria

Soil myxomycetes are crucial soil protists with important ecological functions. Yet, our understanding of their diversity patterns in managed forests and the interactions with their food is far behind other taxa. This study investigates the spatiotemporal patterns of soil myxomycetes in four northern subtropical managed forest types across seasons and aims to identify assembly processes, main predictors of myxomycete communities, and the potential interactions between myxomycetes and bacteria. Results showed that no significant difference in α diversity of myxomycete communities among forest types was observed, but a significant difference was observed in community structures. Significant differences were observed in α diversity and community structures of myxomycetes among seasons. Deterministic processes in each forest type and season dominated myxomycete community assemblies. Soil physicochemical properties and bacterial communities have a significant direct impact on the myxomycete community, while forest types, seasons, and enzyme activities have an indirect effect. There is a significant synergistic covariation between the soil myxomycete community and bacterial community. The genera of the phyla Acidobacteriota, Actinobacteriota, and Bacteroidota have a strong correlation with the richness of myxomycete genera. Overall, this study provides new insight into the diversity of soil myxomycetes and their influence by bacteria, crucial for myxomycetes ecology.IMPORTANCESoil myxomycetes are an important component of soil protists. Our study revealed for the first time the community structure of soil myxomycetes in managed forests of the northern subtropical regions and systematically investigated the seasonal variation patterns of soil myxomycetes. Meanwhile, we further investigated the potential interactions between soil myxomycetes and bacteria. This study will greatly enhance our understanding of the ecology of soil myxomycetes and their biological roles.

Community structure and assembly of myxomycetes in northern Chinese forests under geographic barriers

The study of myxomycete biogeography has a long-standing history and has consistently drawn scholarly interest. Nevertheless, studies focusing specifically on the spatial and temporal distribution patterns of myxomycete diversity are relatively limited, with even fewer investigating the mechanisms driving the generation and maintenance of myxomycete diversity. Therefore, this study selected two geographically distant sampling sites within northern Chinese forests to investigate myxomycete species composition, community structure, environmental drivers, and assembly patterns under geographic barriers. We established plots in the Altai Mountains (ALE) and the Greater Khingan Mountains (GKM), gathered bark and litter, and conducted 80-day moist chamber cultures of myxomycetes. Additionally, myxomycete specimens were collected in the field simultaneously to supplement the data set. This study collected 541 myxomycete specimens belonging to 73 species from 28 genera, spanning 12 families and eight orders. The ALE and the GKM had 20 identical species, accounting for 27% of the total species. Myxomycetes from both regions exhibited abundant occurrence 18 days after cultivation, with the quantity on bark substrates notably higher than on litter. Arcyria pomiformis and Comatricha elegans were the most common species in moist chamber cultures. Mantel test outcomes revealed that environmental factors had no significant impact on myxomycete community similarity between the two areas, aligning with findings from the neutral community model analysis, indicating a predominant influence of stochastic processes on myxomycete community structure in moist chamber cultures. This study represents the first application of a quantitative framework to analyze myxomycete community assembly cultivated in moist chambers.

Unraveling the distribution pattern and driving forces of soil microorganisms under geographic barriers

The Altai Mountains (ALE) and the Greater Khingan Mountains (GKM) in northern China are forest regions dominated by coniferous trees. These geographically isolated regions provide an ideal setting for studying microbial biogeographic patterns. In this study, we employed high-throughput techniques to obtain DNA sequences of soil myxomycetes, bacteria, and fungi and explored the mechanisms underlying the assembly of both local and cross-regional microbial communities in relation to environmental factors. Our investigation revealed that the environmental heterogeneity in ALE and GKM significantly affected the succession and assembly of soil bacterial communities at cross-regional scales. Specifically, the optimal environmental factors affecting bacterial Bray-Curtis similarity were elevation and temperature seasonality. The spatial factors and climate change impact on bacterial communities under the geographical barriers surpassed that of local soil microenvironments. The assembly pattern of bacterial communities transitions from local drift to cross-regional heterogeneous selection. Environmental factors had a relatively weak influence on myxomycetes and fungi. Both soil myxomycetes and fungi faced considerable dispersal limitation at local and cross-regional scales, ultimately leading to weak geographical distribution patterns.IMPORTANCEThe impact of environmental selection and dispersal on the soil microbial spatial distribution is a key concern in microbial biogeography, particularly in large-scale geographical patterns. However, our current understanding remains limited. Our study found that soil bacteria displayed a distinct cross-regional geographical distribution pattern, primarily influenced by environmental selection. Conversely, the cross-regional geographical distribution patterns of soil myxomycetes and fungi were relatively weak. Their composition exhibited a weak association with the environment at local and cross-regional scales, with assembly primarily driven by dispersal limitation.

Advancements in the taxonomic study of myxomycetes (Myxogastrea) in China

Species in the class Myxomycetes (or Myxogastrea) are essential components of biodiversity and play important ecological roles in terrestrial ecosystems, especially in forests. Studies on the taxonomy and diversity of these organisms started late in China. However, significant progress in China has been made in modern taxonomic studies on myxomycetes based on long-term species surveying and specimen collecting. The existing achievements have shown that comprehensive and continuous studies on the taxonomy and diversity of myxomycetes in China have the potential to enhance global biodiversity and improve the geographic distribution pattern of myxomycetes. Therefore, building on the current research foundation and expanding myxomycete research in a wider and more in-depth approach is imperative.