Symbiotic efficiency and genetic characteristics of Bradyrhizobium sp. strain UFSM LA 1.3 isolated from Lupinus albescens (H. et Arn)

Marcos Roberto Dobler Stroschein,Adriana Giongo,Luciano Kaiser Vargas,Flávio Luiz Foletto Eltz,Mateus Padoin Pontelli,Zaida Inês Antoniolli,Manoeli Lupatini

doi:10.1590/s0103-90162010000600012

Marcos Roberto Dobler Stroschein, Adriana Giongo + Show 5 more

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https://doi.org/10.1590/s0103-90162010000600012

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Abstract

Legume species belonging to the genus Lupinus are annual herb plants. The majority of them are indigenous to the Americas. They are known for nitrogen-fixing symbioses with soil bacteria collectively called rhizobia. The aim of this study was to characterize a rhizobium strain isolated from Lupinus albescens using phenotypic, symbiotic and molecular approaches. Strain UFSM LA 1.3 was tested in vitro according to several parameters: colony size, color and growing rate; acid or alkaline reaction in yeast mannitol media supplemented with bromothymol blue; gum production. Molecular characterization was evaluated by PCR technique using primers BOX A1-R and sequence analysis of the 16S-23S rDNA intergenic region (ITS). ITS sequencing fragments showed genetic similarity with Bradyrhizobium sp. The polymorphism observed by BOX-PCR have shown that strain differs from the reference strain SEMIA 928 and SEMIA 938. The symbiotic efficiency under axenic conditions of UFSM LA 1.3 was 94.6%, without statistical differences compared to the mineral nitrogen fertilized control, to which was applied solution of 400 mg of ammonium nitrate.

Highlights

The Southwest region of the state of Rio Grande do Sul (RS), Brazil, has about 5.2% of the area occupied by sandy soils
Constructing the phylogeny with the aligned UFSM LA 1.3 sequence and sequences obtained from GenBank showed that the lupine isolate was closely related to Bradyrhizobium sp
Jarabo-Lorenzo et al (2003) studied bradyrhizobia species isolated from Lupinus spp. and indicated that the Bradyrhizobium strains nodulating this legume represent a huge heterogeneity and their phylogenetic relationships is far from being solved

Summary

Introduction

The Southwest region of the state of Rio Grande do Sul (RS), Brazil, has about 5.2% of the area occupied by sandy soils. Lupinus albescens H. et Arn, a wild species, has been used in the recovery of sandy soils due to its strong adaptability to sandy soils, reducing eolic erosion and fixing nitrogen when associated to rhizobia (Rovedder and Eltz, 2008). Rhizobia can be distinguished based on morphology and growth in yeast mannitol agar (Fred and Waksman, 1932), and using molecular biology techniques for strain characterization. Primers corresponding to consensus repetitive sequences dispersed in the eubacteria genome, known as BOX (enterobacterial repetitive sequences) create characteristic patterns when separated in agarose gels, providing discrimination on strain level (Versalovic et al, 1991)

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