Contrasting adaptations of soil prokaryotes and arbuscular mycorrhizal fungi in saline wildland and non-saline farmland

Understanding the environmental adaptation of microbiota is essential for ecosystem management. However, the difference in community structure of prokaryotes and arbuscular mycorrhizal (AM) fungi between saline wildland and non-saline farmland remains unclear. Here, we performed 18S rDNA sequencing to detect AM fungi and 16S rDNA sequencing to detect prokaryotes for soils collected in wildlands (bareland, Suaeda, and Tamarix lands) and farmlands (cotton and maize lands) in Uzbekistan. Higher beta diversity, stronger effects of ecological drift, and a simplified co-occurrence network were detected for AM fungal community in farmland compared to wildland, likely due to the formation of patchy communities with a small number of individuals (low abundance) caused by tillage and reduced universality of AM fungal community dynamics, i.e., interactions among AM fungi and their environment, might be stable in wildland but not in farmland. In contrast, lower beta diversity, weaker effects of ecological drift and dispersal limitation, and a complexified co-occurrence network were detected for prokaryotic community in farmland than in wildland, likely due to community homogenization caused by tillage that increases the odds of encounters between different prokaryotic taxa. Besides, larger average genome size and higher community-weighted rDNA copy number were detected for prokaryotes in wildland than in farmland, alongside the rise of Acinetobacter members and functional enrichment of stress (salinity) tolerance. Our findings suggest that prokaryotic and AM fungal communities are actively responsive to the changes in salinity, resources, and disturbance, and this pattern could be harnessed for saline land reclamation practices.