Abiotic Factors and Plant Communities Shape the Distribution of Soil Pathogenic Oomycetes in Chinese Grasslands.

The outbreaks of emerging phytopathogens constrain socioeconomic development globally and are expected to intensify in the future along with climate change. Oomycetes, a group of fungus-like eukaryotes, include many phytopathogenic species, making it critical to understand the drivers of their diversity and distribution. This work analyzes 972 soil samples from three major grassland types in China and found that soil phosphorus availability drove oomycete richness, while humidity and nitrogen content affected community composition. Pathogenic oomycete abundance is mostly influenced by precipitation, temperature seasonality, and plant species richness. This work creates a distribution atlas of pathogenic oomycete richness and abundance in Chinese grasslands, using space-for-time methods to predict future outbreak areas under climate change. Model predictions indicate a potential increased risk of oomycete disease in ≈42% of the grassland area under SSP 1-2.6 and SSP 5-8.5 climate scenarios, particularly in portions of typical and meadow grasslands. This study enhances the understanding of the drivers behind the distribution of pathogenic oomycetes and highlights the need for disease management strategies in the face of climate change.