Bradyrhizobia associated with Laburnum anagyroides, an exotic legume grown in Poland

Monika Elżbieta Jach,Ewa Sajnaga

doi:10.1007/s13199-020-00668-x

Abstract

We isolated 18 rhizobial strains from root nodules of a leguminous shrub Laburnum anagyroides (common laburnum) grown in Southeast Poland as an exotic plant. With the use of BOX-PCR fingerprinting, the isolates were clustered into 2 main groups and one separate lineage, which was congruent with the ITS-RFLP results. The phylogenetic trees constructed based on 16S rRNA and combined atpD, dnaK, glnA, and recA gene sequence data separated the representative strains into three evolutionary lineages within the Bradyrhizobium jicamae supergroup, with Bradyrhizobium algeriense and Bradyrhizobium valentinum as the closest relatives. The nodA and nifH gene phylogenies proved that the L. anagyroides symbionts carry a symbiotic gene variant known as Clade IV, representing the symbiovar retamae. Phenotypic characteristics of the isolates and reference strains are also reported. Our study of the rhizobia nodulating L. anagyroides growing in Poland complements earlier few findings on the symbiotic associations of this Genisteae species.

Highlights

Bacteria of the genus Bradyrhizobium (Jordan 1982) and at least 11 other rhizobial genera participate in the process of N2fixing symbiosis with legume plants classified in the family Fabaceae (Lindström et al 2015; Shamseldin et al 2017)
18 rhizobial strains were isolated from root nodules sampled from L. anagyroides grown as a decorative plant in two cities of Southeast Poland (Table 1)
The bacterial strains analyzed here are rhizobia obtained from nodules of L. anagyroides growing in Poland

Summary

Introduction

Bacteria of the genus Bradyrhizobium (Jordan 1982) and at least 11 other rhizobial genera participate in the process of N2fixing symbiosis with legume plants classified in the family Fabaceae (Lindström et al 2015; Shamseldin et al 2017). They can establish symbiosis with all major legume lineages of Fabaceae spp. and even non-legume Parasponia andersonii, which suggests that bradyrhizobia may have been the ancestor of all rhizobia (Hungria et al 2015; Parker 2015). A few earlier studies identified the Spanish L. anagyroides microsymbionts as Bradyrhizobium canariense (Ruiz-Díez et al 2009) and these from Belgium and Croatia as Bradyrhizobium spp. (De Meyer et al 2011; Parker 2015); further investigations are necessary to provide better understanding of the L. anagyroides

Methods

Results

Conclusion