Metagenômica de solos em paisagens agrícolas no Cerrado

Abstract

The microbial community in the soil is highly diverse and is composed mainly of bacteria and fungi with most of these taxa currently undescribed. Here we aimed to understand the effects of landscape composition on soil microbiota diversity. Specifically, we analyzed the effects of landscape and soil variables in the composition, taxonomic, phylogenetic and functional microbial diversity in Cerrado agricultural landscapes. Kraken 2 was able to classify a mean of 7,600 species with more 10 thousand OTU classification per site and Bracken reclassify it to a mean of approximately 3,800 species per site. Archaea sequences were mostly assigned to the highly diverse phylum Euryarchaeota and bacterial sequences were predominancy assigned to the phyla Proteobacteria and Actinobacteria. MG-RAST classification using the SEED subsystems database classified over 8.2 million reads per site within the 28 functional categories. Regarding alpha diversity indexes, soil and landscape variables negatively influenced Archaea and Bacteria species Shannon diversity index, Margalef richness index, MPD and MNTD phylogenetic diversities, richness and abundance. For beta diversity, we found significant interaction with landscape variables of (APSI), percentage of pasture, habitat and forest, and local variable chromium (Cr). Taken together, our results show a taxonomical profile for Archaea and Bacteria of disturbed soils caused by changes in the landscape use. Also, the high values of alpha diversity indexes contrasting with the low values of beta diversity indexes indicate changes in species richness and its heterogeneity. Lastly, APSI and Cr are the two predictive variables that better explained the diversity and richness of Archaea and Bacteria in the Cerrado agricultural landscapes. We found that intensive land use for agriculture increases the species richness and abundance of soil microorganisms while reducing their diversity.