Trichoderma spp. as a bioindicator of soil quality in the Yungas region in NW Argentina.

VORGRIG J; CHIOCCHIO V; MONTECCHIA MS; PUCHEU NL; CORREA OS

Puerto Madryn, Argentina

Congreso; XLVI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

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

This study analyzes the use of Trichoderma spp. in pristine and agricultural soils as a potential microbiological indicator of soil quality. Soils from a 23-year (S23) and two 3-year soybean monocultures (PR3 and I13, respectively), a pristine pedemontane forest (M) and a montane forest (SMR) were sampled. To remove fungal spores from soil, samples were washed following the methodology of Bissett and Widden (1972). Washed soil particles were placed on PDA-rose bengal agar plates and the number of Trichoderma spp. colonies was determined after 8-day at 25ºC and a 8 h of day light period (2,300 lux). High Trichoderma number was observed in the largest (>1.2 mm) soil aggregates. The number of Trichoderma spp. was similar in the two pristine soils (SMR and M), while in agricultural soils only S23 and PR3 showed significant (p<0.05) differences between them, being higher in PR3 than in S23. The frequency of Trichoderma spp. was significantly (p<0.05) lower in S23 than that in PR3 and M. Our results suggest that the frequency of Trichoderma spp. in these soils is affected by the length of time under agricultural use. Nevertheless, further studies on Trichoderma diversity are necessary to determine if one or more species might be used as soil quality indicators in this region.