Structure, composition and metagenomic profile of soil microbiomes associated to agricultural land use and tillage systems in the Argentine Pampas

B. CARBONETTO; N. RASCOVAN; R. ALVAREZ; A. MENTABERRY; M. VAZQUEZ

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2014 vol. 9 p. 1 - 11

1932-6203

griculture is facing a major challenge nowadays: to increase crop production for food and energy while preservingecosystem functioning and soil quality. Argentine Pampas is one of the main world producers of crops and one of the mainadopters of conservation agriculture. Changes in soil chemical and physical properties of Pampas soils due to differenttillage systems have been deeply studied. Still, not much evidence has been reported on the effects of agricultural practiceson Pampas soil microbiomes. The aim of our study was to investigate the effects of agricultural land use on communitystructure, composition and metabolic profiles on soil microbiomes of Argentine Pampas. We also compared the effectsassociated to conventional practices with the effects of no-tillage systems. Our results confirmed the impact on microbiomestructure and composition due to agricultural practices. The phyla Verrucomicrobia, Plactomycetes, Actinobacteria, andChloroflexiwere more abundant in non cultivated soils whileGemmatimonadetes, Nitrospiraeand WS3 were more abundantin cultivated soils. Effects on metabolic metagenomic profiles were also observed. The relative abundance of genes assignedto transcription, protein modification, nucleotide transport and metabolism, wall and membrane biogenesis andintracellular trafficking and secretion were higher in cultivated fertilized soils than in non cultivated soils. We also observedsignificant differences in microbiome structure and taxonomic composition between soils under conventional and notillage systems. Overall, our results suggest that agronomical land use and the type of tillage system have inducedmicrobiomes to shift their life-history strategies. Microbiomes of cultivated fertilized soils (i.e. higher nutrient amendment)presented tendencies to copiotrophy while microbiomes of non cultivated homogenous soils appeared to have a moreoligotrophic life-style. Additionally, we propose that conventional tillage systems may promote copiotrophy more than notillage systems by decreasing soil organic matter stability and therefore increasing nutrient availability.Citation:Carbonetto B, Rascovan N, A´lvarez R, Mentaberry A, Va ´zquez MP (2014) Structure, Composition and Metagenomic Profile of S