Diversidad de los rizobios simbiontes de Desmodium incanum que crecen en Argentina

TONIUTTI, MA; ALBICORO, F.J.; FORNASERO, LV; PENSIERO JF; LAGARES A.; DEL PAPA, M. F

Mar del Plata

Congreso; SAMIGE; 2014

Desmodium incanum is an herbaceous legume native to Argentina. Its perennial characteristics and good adaptability make this legume interesting for animal nutrition and introduction in agricultural management practices. Research on native legumes species well adapted to diverse ecological conditions is an important subject for the agronomic potential that many species show. Little information is available about the symbionts of Desmodium species. To study the genetic diversity of rhizobia associated with Desmodium incanum grown in our country, isolates from temperate and subtropical regions were collected and analysed. A collection of Desmodium nodulating isolates from Argentina was obtained and characterized. A total of 75 rhizobial isolates from 4 Desmodium incanun populations from different geographic locations (Chaco, Santa Fe, Tucuman and Corrientes) were selected and analyzed. The phenotypical characterization included the determination of growth ability under different stressed conditions, whereas the genetic and phylogenetic diversity was assessed through MBOREP, BOXA-PCR, nifH and nodC amplification as well as sequencing of the 16SRNA in selected isolates. Most microsymbionts of Desmodium species belonged to Bradyrhizobium closely related to Bradyrhizobium elkanii, Bradyrhizobium japonicum, Bradyrhizobium liaoningense and Bradyrhizobium yuanmingense. Some small groups or single strain were related to Rhizobium sp. The results indicated high diversity among symbiotic rhizobia. These results offered the first systematic information about the microsymbionts of Desmodium incanum grown in the temperate regions of Argentina. These results open a new line of research on native rhizobia which could be useful for the forage inoculants industry.