Morphophysiological characterization of rhizobia isolated from wild genotypes of the common bean

Fernanda Bueno Sampaio,Claudia Cristina Garcia Martin-Didonet,Adriano Moreira Knupp,Enderson Petrônio De Brito Ferreira,Eliana Paula Fernandes

doi:10.14393/bj-v32n6a2016-33084

Abstract

This study aimed to characterize, based on the morphology and on the use of carbon sources, rhizobial isolates obtained from nodules of wild common bean genotypes cultivated on soil samples from the states of Goias, Minas Gerais and Parana. Based on morphological and carbon source use, similarity matrixes were generated to perform clustering analysis based on the Jaccard index. A total of 523 isolates were obtained with the predominance of isolates that acidify the culture medium and showed fast growth. Isolates from the soils of Araucaria and Prudentopolis produced a greater amount of mucus than those from Jussara, Nova Veneza, Uberlândia and Unai soils. The rhizobia isolates obtained from soils of Goias and Minas Gerais showed greater phenotypic diversity than those from the soils of Parana. Analysis based on the use of different carbon sources revealed that rhizobia isolates obtained from soils of Goias have higher metabolic diversity. Overall, the most part of isolates grouped with the reference strains, especially with the Rhizobium tropici and R. freirei strains used as inoculants for the common bean.

Highlights

The common bean (Phaseolus vulgaris L.) shows great social and economic importance worldwide (BUILES et al, 2011), in addition to being the main source of protein for the poor population
This study aimed to characterize, based on the morphology and on the use of carbon sources, rhizobial isolates obtained from nodules of wild common bean genotypes cultivated on soil samples from the states of Goiás, Minas Gerais and Paraná
The most part of isolates grouped with the reference strains, especially with the Rhizobium tropici and R. freirei strains used as inoculants for the common bean

Summary

INTRODUCTION

The common bean (Phaseolus vulgaris L.) shows great social and economic importance worldwide (BUILES et al, 2011), in addition to being the main source of protein for the poor population. Brazil is the third common bean producer of the world (FAO, 2015), with a harvested area of 2.94 million hectares and grain yield of 1070 kg ha-1 (IBGE, 2015) This crop is able, when associated with soil bacterial known as rhizobia, to perform the biological nitrogen fixation (BNF), which takes place on specialized structures named nodules. According to Vargas and Hungria (1997), studies about the host-specificity of rhizobia strains obtained from the common bean, carried out under Cerrado conditions, provided good information about the amplitude of adaptation of local native rhizobia to a wide range of hosts. This same approach can be applied to other producing regions of the common bean. This work aimed to obtain and to characterize based on morphophysiological parameters, rhizobia isolates from soils of Goiás, Minas Gerais and Paraná states cultivated with wild genotypes of the common bean

MATERIAL AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS