Abstract

HERNANDEZ FORTE, Ionel et al. Phenotypical characterization of rhizobia isolates from forage legume Canavalia ensiformis. cultrop [online]. 2012, vol.33, n.4, pp. 21-28. ISSN 0258-5936.

The objective of this work was to characterize phenotypically rhizobia isolates from forage legume Canavalia ensiformis. Twelve isolates (five possible members of the Rhizobium genus, seven possible members of Bradyrhizobium genus) and two commercial strains, BR 2001 and BR 2003a were characterized. For the phenotypic characterization of the bacterial isolates, their capacity to use six carbohydrates as carbon source, their tolerance to acid condition and different levels of NaCl, and the resistence to six antibiotic, were studied; as well as their growing in three incubation temperatures. In addition, the capacity of these isolates to produce polyhidroxibutirates (PHB) was determinated. All rhizobia isolates used lactose, glucose and mannitol as carbon source. One rapid growing isolate was the most tolerant to pH 4.5. The isolates possible members of the Rhizobium/Sinorhizobium genus were more tolerant to NaCl than the isolates possible members of Bradyrhizobium genus. Three of the rapid growing isolates were resistent to six antibiotics. When the isolates were incubated at 370C, all of them except the CP3 isolate and one commercial strain, BR 2001, grown similar to control. The CP10 slow growing isolate had the capacity to produce the biggest PHB concentration (0.023 g.L-1).

Keywords : Rhizobium; Bradyrhizobium; acidity; salinity.

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