Reassessment of the taxonomic position of Burkholderia andropogonis and description of Robbsia andropogonis gen. nov., comb. nov.

The phylogenetic classification of the species Burkholderia andropogonis within the Burkholderia genus was reassessed using 16S rRNA gene phylogenetic analysis and multilocus sequence analysis (MLSA). Both phylogenetic trees revealed two main groups, named A and B, strongly supported by high bootstrap values (100%). Group A encompassed all of the Burkholderia species complex, whi.le Group B only comprised B. andropogonis species, with low percentage similarities with other species of the genus, from 92 to 95% for 16S rRNA gene sequences and 83% for conserved gene sequences. Average nucleotide identity (ANI), tetranucleotide signature frequency, and percentage of conserved proteins POCP analyses were also carried out, and in the three analyses B. andropogonis showed lower values when compared to the other Burkholderia species complex, near 71% for ANI, from 0.484 to 0.724 for tetranucleotide signature frequency, and around 50% for POCP, reinforcing the distance observed in the phylogenetic analyses. Our findings provide an important insight into the taxonomy of B. andropogonis. It is clear from the results that this bacterial species exhibits genotypic differences and represents a new genus described herein as Robbsia andropogonis gen. nov., comb. nov.

Draft Genome Sequence of Burkholderia andropogonis Type Strain ICMP2807, Isolated from Sorghum bicolor.

Here, we report the draft genome sequence of Burkholderia andropogonis ICMP2807, a phytopathogenic bacterium isolated from Sorghum bicolor plants in the United States.

Comparative metagenomic analysis of coral microbial communities using a reference-independent approach.

By comparing the SEED and Pfam functional profiles of metagenomes of two Brazilian coral species with 29 datasets that are publicly available, we were able to identify some functions, such as protein secretion systems, that are overrepresented in the metagenomes of corals and may play a role in the establishment and maintenance of bacteria-coral associations. However, only a small percentage of the reads of these metagenomes could be annotated by these reference databases, which may lead to a strong bias in the comparative studies. For this reason, we have searched for identical sequences (99% of nucleotide identity) among these metagenomes in order to perform a reference-independent comparative analysis, and we were able to identify groups of microbial communities that may be under similar selective pressures. The identification of sequences shared among the metagenomes was found to be even better for the identification of groups of communities with similar niche requirements than the traditional analysis of functional profiles. This approach is not only helpful for the investigation of similarities between microbial communities with high proportion of unknown reads, but also enables an indirect overview of gene exchange between communities.