Rhizospheric soil bacteria and arbuscular mycorrhizal fungi diversity along altitudinal gradient in South American Puna grassland

M. A. LUGO, E. MENOYO, D. FERNÁNDEZ, C. ESTÉVEZ, M. FERRERO, F. A. SIÑERIZ.

La Plata

Congreso; II Congreso Argentino de Microbiología General (SAMIGE); 2005

Sociedad Argentina de Microbiología General

Arbuscular mycorrhizal fungi (AMF) are main component of the microbial soil community and its diversity is associated with plant community structure and functioning. They are highly effective at capture and translocation of soil nutrients as phosphorus from soil to the plant. AMF interactions with bacteria have synergistic beneficial effect on plant growth, but little is known about these interactions in pot and crop systems. Puna is a South American stressed biogeographic región with unique features. Rhizospheric soil samples were taken along altitudinal gradient and fungal diversity and culturable bacteria associated were analyze using morphological and molecular methods. Five sample sites were placed along an altitudinal gradient between 3320 and 3870 masl in the Puna mountain grassland samples were collected from each 6 grass species as host, in each site. The AMF spores were extracted from soil by wet sieving and sucrose centrifugation and their diversity (density and richness) was quantified at 500X magnification under dissecting microscope using the gridline methods. Bacterial count was determined as CFU/g of soil by serial dilution of suspended soil and further grown over R2A médium piales. The genomic DNA extracted from several bacteria colonies grown over these piales was used as target in PCR reactions, using universal primer for Bacteria. Amplicons of 16S rRNA gene were subsequent purified and sequenced for identification of bacteria.