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Aim: Soil‐borne pathogens severely affect crop production, but the present distribution of agricultural soil‐borne pathogens and their response to global changes are unexplored at large spatial scales. Here, we examine the nationwide‐scale distribution patterns, dominant taxa and environmental drivers of fungal soil‐borne pathogens, and their response to warming, nutrient enrichment and their interaction. Location: China. Time period: July and August 2019. Major taxa studied: Fungal plant pathogens. Methods: Through nationwide field surveys of 711 top‐ and subsoil samples in 51 cropland locations, we investigated the distribution patterns, environmental drivers and dominant taxa of fungal plant pathogens. We then conducted a mesocosm experiment with soils collected at 40 survey locations to evaluate the response patterns of fungal pathogens to global changes, including warming, nutrient enrichment and their interaction. Results: We observed that the abundance and richness of potential soil‐borne pathogens were higher in the topsoil than in the subsoil. Mean annual temperature and mean annual precipitation as the main drivers had a stronger effect on the abundance, richness and community of pathogens in the topsoil than subsoil. Two phylotypes, belonging to genus Fusarium, were the dominant soil‐borne pathogens accounting for approximately one third of total abundance, and their abundances (e.g. relative and absolute abundance via quantitative polymerase chain reaction) were negatively correlated with precipitation and temperature. The mesocosm experiment simulating global changes further revealed that the abundance and richness distributions of soil pathogens predicted the direction of their response to global changes, with a positive response in pathogen‐poor soil and negative in pathogen‐rich soil. We further constructed spatial atlases of the dominant soil‐borne pathogens and their responses to global changes in agricultural fields. Main conclusions: Our findings suggest that the current distribution of potential soil‐borne pathogens is regulated by climate, which could affect their future dynamics and is vital to agricultural practices for pathogen control and crop production. [ABSTRACT FROM AUTHOR]

Aim: Climate change is the foremost cause of terrestrial biodiversity decline, but the microbial communities from different habitats do not respond equally to environmental change. However, our understanding of the response patterns of microbial diversity to climate change remains limited in distinct agriculture ecosystems across large spatial scales. Here, we explore the response patterns of soil bacterial community structure and function to dry–wet cycles in dryland (maize) and paddy (rice) agricultural ecosystems throughout eastern China. Location: Eastern China. Time period: November 2019 to May 2020. Major taxa studied: Bacterial communities. Methods: Incubation experiments with dry–wet cycles were carried out on the soil samples collected from 25 paired maize and rice fields across eastern China. Bacterial community structure was estimated via high‐throughput sequencing techniques. We applied quantitative polymerase chain reaction to evaluate the effect of the dry–wet cycle on the change of functional genes. Phylogenetic signals were examined based on Blomberg's K to test the phylogenetic conservatism of maize and rice bacterial communities during dry–wet cycles. Results: Dry–wet cycles significantly decreased bacterial alpha diversity in both maize and rice soils, and bacterial communities from warmer regions were more sensitive to dry–wet cycles. The bacterial responses to dry–wet cycles were phylogenetically conserved, with greater phylogenetic conservation in the former. The abundance of functional genes that were related to carbon decomposition, nitrogen fixation, nitrification, denitrification and organophosphorus mineralization decreased during dry–wet cycles, and the resistances of such functional genes to disturbance were stronger in rice soils than in maize soils. In addition, the relative abundances of stable amplicon sequence variants during dry–wet cycles had a significant positive linear relationship with functional gene abundance in the maize and rice soils, indicating their essential roles in the stability of microbial function. Main conclusions: We conclude that soil bacterial community structure and function in dryland agricultural ecosystems are less stable and exhibit greater phylogenetic conservation in response to dry–wet cycles when compared with paddy fields. In addition, our study reveals, for the first time, the response patterns of bacterial communities to dry–wet cycles in dryland and wetland agroecosystems. [ABSTRACT FROM AUTHOR]

Aim: A predictive understanding of the mechanisms underlying microbial biogeographical patterns is of great interest, particularly with respect to phylogenetic distributions of their ecological adaptations. Here, we test whether phylogenetic information can predict the biogeographical distributions, community assembly and species co‐occurrence of soil archaea. Location: Northern China. Time period: July and August 2017. Major taxa studied: Archaeal communities. Methods: By conducting a large‐scale (transect intervals of 1,257.6 km) study across agricultural field, forest, wetland, grassland and desert biomes, we applied the phylogenetic framework of niche conservatism to investigate archaeal biogeography, community assembly and network topology. We examined the phylogenetic signal based on Blomberg's K to test whether the environmental preference of a given archaeal taxon was related to the phylogeny, corresponding to the degree of phylogenetic conservatism for environmental niches across complex environmental gradients. We evaluated the assembly processes of archaeal communities based on null model and Sloan neutral model analyses. We then explored the major factors that influenced the species coexistence and assembly processes of soil archaeal communities. Results: Soil archaeal taxa exhibited strong climate‐related niche conservatism of ecological preferences. Mean annual precipitation (MAP) had the strongest phylogenetic signal, and this mediated both community assembly processes and species coexistence, with stronger deterministic assembly and less species coexistence in environments with lower precipitation. Phylogenetic diversity was closely linked to the balance of community assembly processes; that is, stochastic assembly processes were dominant in low‐diversity communities, whereas variable selection of deterministic processes promoted high phylogenetic diversity. Main conclusions: We conclude that strong phylogenetic niche conservatism of soil archaea drives their biogeographical distributions. Our findings represent a considerable advance in linking phylogenetic niche conservatism to soil archaeal biogeography, community assembly and species coexistence, and therefore forecasting soil archaeal evolutionary adaptations in response to ongoing environmental changes. [ABSTRACT FROM AUTHOR]

Aim Location Time period Major taxa studied Methods Results Main conclusions Revealing the role of regional species pool size in community assembly rules is essential for extending the species‐pool framework to large‐scale community ecology, and thus for more comprehensive understanding of biodiversity formation. However, little has been done to couple the regional species‐pool effect into local ecological processes in soil fungal communities, which play essential roles in ecosystems worldwide. Here, we performed large‐scale soil surveys of fungal communities to examine the linkage between regional species pool size and Dispersal–Selection Relationships (DSRs), and their relations to community structure.China.July–August 2019.Fungal communities.By conducting the nationwide soil survey of ~1200 samples from various ecosystems across China, including agricultural, forest, grassland, and wetland soils, we examined the linkage between regional species pool size and DSRs, and their relationship to fungal community structure.We found that selection was negatively related to dispersal, which was consistent with the general view that the strength of selection is weakened by dispersal homogenization, and that this relationship was stronger in regions with larger species pools. Moreover, an increase in community dispersion was correlated with stronger effect size of DSRs, implying greater heterogeneity among fungal communities under larger species pools.Our study clearly illustrates the association of regional species pool size with local assembly rules and community formation of soil fungi across terrestrial ecosystems. [ABSTRACT FROM AUTHOR]