Distinct taxonomic composition of soil bacterial community across a native gradient of Cerrado-Ecotone-Caatinga

Abstract Biodiversity underlies ecosystem functioning, and the soil microbiome plays a crucial role in these functional processes. A better understanding of the soil microbiome and the relationship between microbial diversity and environmental parameters would increase our ability to set conservation priorities. In recent years, ecotones have been considered an important issue in ecological studies since they are ecosystems located in the transition between two biomes where communities meet and integrate. Here, we hypothesized that each area of the environmental gradient Cerrado-Ecotone-Caatinga would harbor a distinct bacterial community mainly shaped by the differential environmental factors. To test this hypothesis, the bacterial community was assessed using the 16S rRNA gene sequencing and correlated with environmental parameters. Our analysis revealed that each area presented a distinct community structure and composition that was related to changes in environmental parameters such as pH, Al, and temperature. Although we did not find significant differences in the microbial diversity, the network analysis showed a gradient with a decreased complexity from the Cerrado to Caatinga also as a response of the soil characteristics, with changes in the number of correlations and the proportion of co-occurrence and competition. Also, the compositional analysis revealed that the most abundant bacterial group in each area is related to functional adaptation to soil properties. Overall, our findings expand our knowledge about the microbiome of these areas and add important information that can be suitable for future ecosystem exploration and the development of preservation strategies.