Microbial diversity in pristine, deforested and agricultural soils from the yungas in Argentina

MONTECCHIA, MARCELA S.; CORREA, OLGA S.; PUCHEU, NORMA L.; KERBER, NORMA L.; GARCIA, AUGUSTO F.

Mar del Plata, Buenos Aires, Argentina

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2007

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Although the Yungas ecoregion is well known for its enormous diversity of flora and fauna, no studies looked at the soil microbial diversity. We analyzed soil samples from native forest, mountain and pedemountain forests, a field recently deforested and cultivated with soybean, and fields with sugarcane (40 or 100 years) or soybean (20 years) monoculture. PCR-DGGE analysis of 16S rRNA genes was used to study whether differences exist among bacterial communities inhabiting these soils. Characteristic DGGE fingerprints were obtained for the soil microbial community from each sampling site. Cluster analysis based on DGGE banding patterns indicated that soil bacterial communities from sugarcane fields were similar to each other but different from that characterizing the pristine adjacent soil. Coincidentally, DGGE profiles of bacterial communities of the recently deforested soil were similar to those of a soybean field with 26 years of agriculture and significantly different from those of the adjacent native forest. Microbial communities from forest mountain soils clustered separately from all the others communities and also showed the highest bacterial diversity as revealed by the number of bands in their DGGE profiles. The structure of bacterial communities was different among the soils analyzed and these differences depended on geographical location and their agricultural use.