Publications by authors named "Juanita Avontuur"

comprises a diverse group of bacteria with various lifestyles. Although best known for their nodule-based nitrogen-fixation in symbiosis with legumes, a select group of bradyrhizobia are also capable of photosynthesis. This ability seems to be rare among rhizobia, and its origin and evolution in these bacteria remain a subject of substantial debate.

View Article and Find Full Text PDF

Since the discovery of Paraburkholderia tuberum, an indigenous South African species and one of the first beta-rhizobia described, several other South African rhizobial Paraburkholderia species have been recognized. Here, we investigate the taxonomic status of 31 rhizobial isolates from the root nodules of diverse South African legume hosts in the Core Cape Subregion, which were initially identified as P. tuberum.

View Article and Find Full Text PDF

Africa is known for its rich legume diversity with a significant number of endemic species originating in South Africa. Many of these legumes associate with rhizobial symbionts of the genus Bradyrhizobium, of which most represent new species. Yet, none of the Bradyrhizobium species from South Africa have been described.

View Article and Find Full Text PDF

Previous studies have recognized South and Central/Latin American mimosoid legumes in the genera Mimosa, Piptadenia and Calliandra as hosts for various nodulating Paraburkholderia species. Several of these species have been validly named in the last two decades, e.g.

View Article and Find Full Text PDF

Twelve nodulating Paraburkholderia strains isolated from indigenous South African fynbos legume Hypocalyptus sophoroides were investigated to determine their taxonomic status. Genealogical concordance analysis, based on six loci (16S rRNA, atpD, recA, rpoB, lepA and gltB), revealed that they separate into two consistent and exclusive groups. Average nucleotide identity and DNA-DNA hybridisation comparisons indicated that they were sufficiently divergent from their closest known phylogenetic relatives (Paraburkholderia caledonica and Paraburkholderia terrae, respectively) to be regarded as novel species.

View Article and Find Full Text PDF

Bradyrhizobium is thought to be the largest and most diverse rhizobial genus, but this is not reflected in the number of described species. Although it was one of the first rhizobial genera recognised, its taxonomy remains complex. Various contemporary studies are showing that genome sequence information may simplify taxonomic decisions.

View Article and Find Full Text PDF

With the increased availability of genome sequences for bacteria, it has become routine practice to construct genome-based phylogenies. These phylogenies have formed the basis for various taxonomic decisions, especially for resolving problematic relationships between taxa. Despite the popularity of concatenating shared genes to obtain well-supported phylogenies, various issues regarding this combined-evidence approach have been raised.

View Article and Find Full Text PDF

The Erwiniaceae contain many species of agricultural and clinical importance. Although relationships among most of the genera in this family are relatively well resolved, the phylogenetic placement of several taxa remains ambiguous. In this study, we aimed to address these uncertainties by using a combination of phylogenetic and genomic approaches.

View Article and Find Full Text PDF

Although the taxonomy of has been extensively scrutinized, significant uncertainty remains regarding the generic boundaries and composition of this large and heterogeneous taxon. Here we used the amino acid and nucleotide sequences of 106 conserved proteins from 92 species to infer robust maximum likelihood phylogenies with which to investigate the generic structure of sensu lato. These data unambiguously supported five distinct lineages, of which four correspond to sensu stricto and the newly introduced genera , , and .

View Article and Find Full Text PDF

Despite the diversity of Burkholderia species known to nodulate legumes in introduced and native regions, relatively few taxa have been formally described. For example, the Cape Floristic Region of South Africa is thought to represent one of the major centres of diversity for the rhizobial members of Burkholderia, yet only five species have been described from legumes occurring in this region and numerous are still awaiting taxonomic treatment. Here, we investigated the taxonomic status of 12 South African root-nodulating Burkholderia isolates from native papilionoid legumes (Hypocalyptus coluteoides, H.

View Article and Find Full Text PDF