Genetic diversity of Azospirillum brasilense in the sugracane cropping area of Tucumán, Argentina

PEDRAZA, RAÚL OSVALDO; DIAZ RICCI, JUAN CARLOS; BELLONE, CARLOS HORACIO

Rio de Janeiro. Brasil

Conferencia; 22º Latin-american Conference on Rhizobiology. RELAR 2004; 2004

RELAR

Native Azospirillum strains are well adapted to the soil environment, although ecological factors that affect the promotion or inhibition of natural populations are not entirely understood. The  aim of this study was to assess the diversity of Azospirillum associated with sugarcane roots as influenced by environmental characteristics. The sampled area corresponded to approximately 200,000 hectares, divided into three regions: West, Central and East, according to their environmental characteristics (e.g.: soil type, texture, pH, organic matter content, rainfall, evapotranspiration). Twelve localities were considered within the West region, five within the Central, and thirteen localities within the East region. From each place, ten local strains were isolated. The bacterial isolation was from surface sterilized roots, according to Döbereiner et al. (1995). The strain identification was carried out according to Döbereiner et al. (1995) and by the amplification and enzyme restriction of a fragment of the gene 16SrDNA, according to Grifoni et  al. (1995). To validate the bacterial identification, reference strains of Azospirillum, obtained from CNPq-EMBRAPA, Rio de Janeiro, were used.