Krishnaveni Palaniappan

Genome data provides high support for generic boundaries in Burkholderia sensu lato

Although the taxonomy of Burkholderia 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 Burkholderia sensu lato. These data unambiguously supported five distinct lineages, of which four correspond to Burkholderia sensu stricto and the newly introduced genera Paraburkholderia, Caballeronia, and Robbsia. The fifth lineage was represented by P. rhizoxinica. Based on these findings, we propose 13 new combinations for those species previously described as members of Burkholderia but that form part of Caballeronia. These findings also suggest revision of the taxonomic status of P. rhizoxinica as it is does not form part of any of the genera currently recognized in Burkholderia sensu lato. From a phylogenetic point of view, Burkholderia sensu stricto has a sister relationship with the Caballeronia+Paraburkholderia clade. Also, the lineages represented by P. rhizoxinica and R. andropogonis, respectively, emerged prior to the radiation of the Burkholderia sensu stricto+Caballeronia+Paraburkholderia clade. Our findings therefore constitute a solid framework, not only for supporting current and future taxonomic decisions, but also for studying the evolution of this assemblage of medically, industrially and agriculturally important species.

Draft Genome Sequence of Frankia sp. Strain DC12, an Atypical, Noninfective, Ineffective Isolate from Datisca cannabina

ABSTRACT Frankia sp. strain DC12, isolated from root nodules of Datisca cannabina, is a member of the fourth lineage of Frankia, which is unable to reinfect actinorhizal plants. Here, we report its 6.88-Mbp high-quality draft genome sequence, with a G+C content of 71.92% and 5,858 candidate protein-coding genes.

Absence of genome reduction in diverse, facultative endohyphal bacteria.

Fungi interact closely with bacteria, both on the surfaces of the hyphae and within their living tissues (i.e. endohyphal bacteria, EHB). These EHB can be obligate or facultative symbionts and can mediate diverse phenotypic traits in their hosts. Although EHB have been observed in many lineages of fungi, it remains unclear how widespread and general these associations are, and whether there are unifying ecological and genomic features can be found across EHB strains as a whole. We cultured 11 bacterial strains after they emerged from the hyphae of diverse Ascomycota that were isolated as foliar endophytes of cupressaceous trees, and generated nearly complete genome sequences for all. Unlike the genomes of largely obligate EHB, the genomes of these facultative EHB resembled those of closely related strains isolated from environmental sources. Although all analysed genomes encoded structures that could be used to interact with eukaryotic hosts, pathways previously implicated in maintenance and establishment of EHB symbiosis were not universally present across all strains. Independent isolation of two nearly identical pairs of strains from different classes of fungi, coupled with recent experimental evidence, suggests horizontal transfer of EHB across endophytic hosts. Given the potential for EHB to influence fungal phenotypes, these genomes could shed light on the mechanisms of plant growth promotion or stress mitigation by fungal endophytes during the symbiotic phase, as well as degradation of plant material during the saprotrophic phase. As such, these findings contribute to the illumination of a new dimension of functional biodiversity in fungi.

Permanent draft genome of Thermithiobacillus tepidarius DSM 3134T, a moderately thermophilic, obligately chemolithoautotrophic member of the Acidithiobacillia

Thermithiobacillus tepidarius DSM 3134T was originally isolated (1983) from the waters of a sulfidic spring entering the Roman Baths (Temple of Sulis-Minerva) at Bath, United Kingdom and is an obligate chemolithoautotroph growing at the expense of reduced sulfur species. This strain has a genome size of 2,958,498 bp. Here we report the genome sequence, annotation and characteristics. The genome comprises 2,902 protein coding and 66 RNA coding genes. Genes responsible for the transaldolase variant of the Calvin-Benson-Bassham cycle were identified along with a biosynthetic horseshoe in lieu of Krebs’ cycle sensu stricto. Terminal oxidases were identified, viz. cytochrome c oxidase (cbb3, EC 1.9.3.1) and ubiquinol oxidase (bd, EC 1.10.3.10). Metalloresistance genes involved in pathways of arsenic and cadmium resistance were found. Evidence of horizontal gene transfer accounting for 5.9 % of the protein-coding genes was found, including transfer from Thiobacillus spp. and Methylococcus capsulatus Bath, isolated from the same spring. A sox gene cluster was found, similar in structure to those from other Acidithiobacillia – by comparison with Thiobacillus thioparus and Paracoccus denitrificans, an additional gene between soxA and soxB was found, annotated as a DUF302-family protein of unknown function. As the Kelly-Friedrich pathway of thiosulfate oxidation (encoded by sox) is not used in Thermithiobacillus spp., the role of the operon (if any) in this species remains unknown. We speculate that DUF302 and sox genes may have a role in periplasmic trithionate oxidation.

Complete Genome Sequences of Caldicellulosiruptor sp. Strain Rt8.B8, Caldicellulosiruptor sp. Strain Wai35.B1, and “Thermoanaerobacter cellulolyticus”

ABSTRACT The genus Caldicellulosiruptor contains extremely thermophilic, cellulolytic bacteria capable of lignocellulose deconstruction. Currently, complete genome sequences for eleven Caldicellulosiruptor species are available. Here, we report genome sequences for three additional Caldicellulosiruptor species: Rt8.B8 DSM 8990 (New Zealand), Wai35.B1 DSM 8977 (New Zealand), and “Thermoanaerobacter cellulolyticus” strain NA10 DSM 8991 (Japan).

High-quality genome sequence of the radioresistant bacterium Deinococcus ficus KS 0460

The genetic platforms of Deinococcus species remain the only systems in which massive ionizing radiation (IR)-induced genome damage can be investigated in vivo at exposures commensurate with cellular survival. We report the whole genome sequence of the extremely IR-resistant rod-shaped bacterium Deinococcus ficus KS 0460 and its phenotypic characterization. Deinococcus ficus KS 0460 has been studied since 1987, first under the name Deinobacter grandis, then Deinococcus grandis. The D. ficus KS 0460 genome consists of a 4.019 Mbp sequence (69.7% GC content and 3894 predicted genes) divided into six genome partitions, five of which are confirmed to be circular. Circularity was determined manually by mate pair linkage. Approximately 76% of the predicted proteins contained identifiable Pfam domains and 72% were assigned to COGs. Of all D. ficus KS 0460 proteins, 79% and 70% had homologues in Deinococcus radiodurans ATCC BAA-816 and Deinococcus geothermalis DSM 11300, respectively. The most striking differences between D. ficus KS 0460 and D. radiodurans BAA-816 identified by the comparison of the KEGG pathways were as follows: (i) D. ficus lacks nine enzymes of purine degradation present in D. radiodurans, and (ii) D. ficus contains eight enzymes involved in nitrogen metabolism, including nitrate and nitrite reductases, that D. radiodurans lacks. Moreover, genes previously considered to be important to IR resistance are missing in D. ficus KS 0460, namely, for the Mn-transporter nramp, and proteins DdrF, DdrJ and DdrK, all of which are also missing in Deinococcus deserti. Otherwise, D. ficus KS 0460 exemplifies the Deinococcus lineage.

Draft Genome Sequence of Methylocapsa palsarum NE2T, an Obligate Methanotroph from Subarctic Soil

ABSTRACT Methylocapsa palsarum NE2T is an aerobic, mildly acidophilic, obligate methanotroph. Similar to other Methylocapsa species, it possesses only a particulate methane monooxygenase and is capable of atmospheric nitrogen fixation. The genome sequence of this typical inhabitant of subarctic wetlands and soils also contains genes indicative of aerobic anoxygenic photosynthesis.

Draft Genome Sequence of Pseudomonas azotifigens Strain DSM 17556T (6H33bT), a Nitrogen Fixer Strain Isolated from a Compost Pile.

ABSTRACT Pseudomonas azotifigens strain 6H33bT is a nitrogen fixer isolated from a hyperthermal compost pile in 2005 by Hatayama and collaborators. Here we report the draft genome, which has an estimated size of 5.0 Mb, exhibits an average G+C content of 66.73%, and is predicted to encode 4,536 protein-coding genes and 100 RNA genes.

Genome Sequence of Polycyclovorans algicola Strain TG408, an Obligate Polycyclic Aromatic Hydrocarbon-Degrading Bacterium Associated with Marine Eukaryotic Phytoplankton

ABSTRACT Polycyclovorans algicola strain TG408 is a recently discovered bacterium associated with marine eukaryotic phytoplankton and exhibits the ability to utilize polycyclic aromatic hydrocarbons (PAHs) almost exclusively as sole sources of carbon and energy. Here, we present the genome sequence of this strain, which is 3,653,213 bp, with 3,477 genes and an average G+C content of 63.8%.

Application of Long Sequence Reads To Improve Genomes for Clostridium thermocellum AD2, Clostridium thermocellum LQRI, and Pelosinus fermentans R7

ABSTRACT We and others have shown the utility of long sequence reads to improve genome assembly quality. In this study, we generated PacBio DNA sequence data to improve the assemblies of draft genomes for Clostridium thermocellum AD2, Clostridium thermocellum LQRI, and Pelosinus fermentans R7.