Biodiversity of Mimosa pudica rhizobial symbionts (Cupriavidus taiwanensis, Rhizobium mesoamericanum) in New Caledonia and their adaptation to heavy metal-rich soils

Abstract

Rhizobia are soil bacteria able to develop a nitrogen-fixing symbiosis with legumes. They are taxonomically spread among the alpha and beta subclasses of the Proteobacteria. Mimosa pudica, a tropical invasive weed, has been found to have an affinity for beta-rhizobia, including species within the Burkholderia and Cupriavidus genera. In this study, we describe the diversity of M. pudica symbionts in the island of New Caledonia, which is characterized by soils with high heavy metal content, especially of Ni. By using a plant-trapping approach on four soils, we isolated 96 strains, the great majority of which belonged to the species Cupriavidus taiwanensis (16S rRNA and recA gene phylogenies). A few Rhizobium strains in the newly described species Rhizobium mesoamericanum were also isolated. The housekeeping and nod gene phylogenies supported the hypothesis of the arrival of the C. taiwanensis and R. mesoamericanum strains together with their host at the time of the introduction of M. pudica in New Caledonia (NC) for its use as a fodder. The C. taiwanensis strains exhibited various tolerances to Ni, Zn and Cr, suggesting their adaptation to the specific environments in NC. Specific metal tolerance marker genes were found in the genomes of these symbionts, and their origin was investigated by phylogenetic analyses.

Genetic Variability and Symbiotic Efficiency of Erythrina velutina Willd. Root Nodule Bacteria from the Semi-Arid Region in Northeastern Brazil

“…Amplification of an intragenic nodA gene fragment using a NodAforB and NodArevB primer set can exhibit positive results, with sizes ranging from 245 to 800 bp (Klonowska et al, 2012;Taulé et al, 2012). So, the amplification of different molecular size amplicons found in the present study can be considered positive for both bacteria, indicating that ESA 71 exhibits a nodA gene copy with some similarity to that found in the Paraburkholderia.…”

“…PCR for amplification of nodC gene from β-rhizobia was carried out using the primers NodCforB (CTCAATGTACACARNGCRTA) and NodCrevB (GAYATGGARTAYTGGYT) (Elliott et al, 2007). For amplification of the nodA gene from β-rhizobia, the primers NodAforB (CRGTGGARGGTBYGYTGGGA) and NodArevB (TCAYARCTCDGGBCCGTTBCG) (Klonowska et al, 2012) were applied. For the PCR of the nodC gene for α-rhizobia, the primers NodCF (AYGTHGTYGAYGACGGTTC) and NodCR(I) (CGYGACAGCCANTCKCTATTG) were used (Laguerre et al, 2001).…”

Novel Cupriavidus Strains Isolated from Root Nodules of Native Uruguayan Mimosa Species

“…Interestingly, these endemics have little or no capacity to interact with Mimosa symbionts from other centers of Mimosa diversity, suggesting coevolution with their particular microsymbionts, which is likely to be a consequence of the soil microbiota pertaining to their very specialized (mainly highland) environments. In contrast to the endemic Mimosa species, the invasive ones are capable of nodulating with a wide range of symbiont types, both alpha-and beta-rhizobial (7,9,16,27,28).…”

Ocorrência, caracterização e identificação de bactérias diazotróficas em simbiose com Mimosa spp. em áreas de solo ultramáfico

“…Dentre as beta-proteobactérias Burkholderia e Cupriavidus estão agrupadas entre os gêneros capazes de formar nódulos em leguminosas, apresentando diversas espécies hospedeiras dentro do gênero Mimosa (MOULIN et al, 2001;CHEN et al, 2001;VANDAME;COENYE , 2004;FERREIRA, 2012;KLONOWSKA, 2012 (BENHIZIA et al, 2004;SHIRAISHI et al, 2010). Para os isolados do presente estudo, outros tipos de análises devem ser realizadas, podendo-se levar em consideração técnicas de microscopia ótica e eletrônica, além de técnicas imunológicas e genéticas, que podem ser usadas para rastrear bactérias, genes, enzimas e/ou metabólitos induzidos pela interação bactéria-planta (REIS, 2006 …”

“…Nenhum dos isolados avaliados nesse trabalho pode ser caracterizado como tolerante a Ni, ou seja, capaz de crescer em concentrações maiores que 5 mM desse metal (KLONOWSKA et al, 2012 Pseudomonas spp. Além disso, outros trabalhos também têm mostrado que dentro do gênero Burkholderia nem todos os isolados podem ser capazes de produzir essa molécula de baixo peso molecular (CABALLERO-MELLADO et al, 2007;SUÁREZ-MORENO et al, 2012;COMPANT et al, 2008).…”