Deciphering soil environmental regulation on reassembly of the soil bacterial community during wetland restoration.

Soil bacteria are vital to regulate biogeochemical processes in wetlands, however, little is known about the patterns and mechanisms of soil bacterial re-organization during wetland restoration. Here, we used a space-for-time substitution approach and examined the ecological processes that drive soil bacterial assembly from cultivated to restored to natural wetlands. Results showed a decrease of soil bacterial α diversity and increase of bacterial community similarity and bacterial interaction (cooperation vs. competition) with years of restoration, which was dominantly influenced by deterministic processes. Identified bacterial keystone taxa (e.g. Variibacter, Acidibacter) with nutrient metabolism capacity exerted strong positive effect on bacterial interaction. Furthermore, changes of soil water condition and nutrient status showed dominantly direct positive effects on soil bacterial reassembly, while falling soil pH significantly promoted bacterial reassembly by increasing keystone taxa and bacterial interaction during wetland restoration. Overall, findings highlighted the crucial role of environmental filtering and its pathway in influencing keystone bacterial taxa that promotes the reassembly of bacterial community during wetland restoration. Our work thus provides a new crucial and timely insight for improving the management of soil bacterial community assembly within the plethora of current and future wetland restoration projects.