Response of soil fungal community composition and functions on the alteration of precipitation in the grassland of Loess Plateau

Abstract A change in precipitation caused by climate change is an important factor that affects the biodiversity and ecological function of arid and semi-arid regions, but its influence on the composition and function of the soil fungi community in the grasslands of the Loess Plateau remains unclear. To fill this knowledge gap, we conducted an in-situ simulation experiment using five precipitation gradients (natural precipitation, increased and decreased by 40%, and 80%) in a natural restoration grassland for three years. The composition of soil fungal communities and their functions were analyzed using high-throughput sequencing techniques. Although the change of precipitation did not change the diversity index of soil fungi, it changed the composition and function of dominant fungal community groups. Specifically, decreased precipitation resulted in an increase in the relative abundance of Dothideomycetes and Boeremia by up to 12.17% and 9.93%, respectively, while these decreased with increased precipitation. The abundance of Basidiomycota, Glomeromycota, and Agaricomycetes abundance decreased by up to 11.27%, 6.96%, and 11.46% with decreased precipitation, but also decreased by up to 10.9%, 1.73%, and 10.51% with increased precipitation, respectively. However, the abundance of Ascomycota, Pezizomycetes, and norank_Pezizales increased by up to 22.58%, 7.45%, and 6.95% with decreased precipitation, and increased by up to 12.05%, 8.43%, and 5.81% with increased precipitation, respectively. The number of dominant fungal groups with interactive relationships weakened by 34.93% and 8.7% under decreased precipitation by 80% and increased 80%, respectively. Precipitation change had no significant effect on the proportion of saprotrophs, while a decrease of precipitation increased the endophyte-plant pathogens by up to 58.0% and decreased arbuscular mycorrhizal fungi by up to 92.6%. In brief, the dominant soil fungal communities could adapt and respond to climate change by altering the proportion of different dominant fungal groups by responding to moisture patterns with changes in the interrelationships between microbial communities and the proportional distribution of functional groups.