INGEBI   02650
INSTITUTO DE INVESTIGACIONES EN INGENIERIA GENETICA Y BIOLOGIA MOLECULAR "DR. HECTOR N TORRES"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A polyphasic study of microbial community structure and function in no-till agricultural soils under different managements in Argentina
Autor/es:
ALEJANDRO FERRARI; EVA FIGUEROLA; LUCIANO ANDRÉS GABBARINI; L GUERRERO; BETINA AGARAS; DALILA REYNA; S ROSA; JUAN PABLO FRENE; S RAVNSKOV; CLAUDIO VALVERDE; L ERIJMAN; LUIS GABRIEL WALL
Lugar:
Corfu
Reunión:
Simposio; 11th Symposium on Bacterial Genetics and Ecology; 2011
Institución organizadora:
University of Athens, Greece
Resumen:
The BIOSPAS project aims to understand how the microbial structure and function in soil under no-till farming are related to agricultural practices and soil properties. Three treatments were defined according to land use and sustainable productivity based on farmers? records: 1) Sustainable agricultural management, subjected to intensive crop rotation, rational nutrient amendment (GOOD Practices), 2) Non-sustainable agricultural management with high mono-cropping without nutrient reposition (BAD Practices), 3) Natural environment. Blocks of treatments were replicated 4 times in agricultural fields that had documented history of no-till management, at sites located across a west-east transect in Argentina´s Pampas. Each sample was collected in triplicate, as a composite of 16 soil subsamples from 0-10 cm depth collected at 50 m intervals. Fatty acids in different soil lipid fractions were analyzed by MIDI. The bacterial metapopulation analysis was assayed by tag-16S rDNA pyrosequencing; the relative abundance of major taxonomic groups of bacteria was estimated using primer-specific qPCR; pseudomonads counts and diversity were evaluated in the culturable fraction by molecular analysis of oprF and gacA markers; physiological activity in soil was assessed with phosphatase, chitinase, and cellulase fluorometric enzymatic assays; Glomalin Related Soil Proteins (GRSP) were surveyed along with key soil variables (pH, moisture, organic carbon content, total nitrogen and P). Principal component analysis of fatty acids was able to separate soil management independently of site. Multivariate analysis of 16S rDNA sequences highlights specific bacterial groups present in a particular soil management. Patterns of significant differences between treatments were obtained at the broad level of examined bacterial taxonomic resolution by qPCR, but for most taxonomic groups the differences were site-specific. The use of gacA primers show pseudomonads population diversity grouping according to geographical sites. Pseudomonads populations varied with soil management within each site. Physiologically, soil enzymatic activities and GRSP data separated soil management independently of sites. The results indicate that no-till systems support distinctive bacterial community composition and function, and highlight the potential of these tools to identify biological data that may serve as potential indicators of agricultural soil management.