Draft Genome Sequence of Two Marine Plantactinospora spp. from the Gulf of California

Shotgun Metagenomics Reveals Minor Micro"bee"omes Diversity Defining Differences between Larvae and Pupae Brood Combs

Bees represent not only a valuable asset in agriculture, but also serve as a model organism within contemporary microbiology. The metagenomic composition of the bee superorganism has been substantially characterized. Nevertheless, traditional cultural methods served as the approach to studying brood combs in the past. Indeed, the comb microbiome may contribute to determining larval caste differentiation and hive immunity. To further this understanding, we conducted a shotgun sequencing analysis of the brood comb microbiome. While we found certain similarities regarding species diversity, it exhibits significant differentiation from all previously described hive metagenomes. Many microbiome members maintain a relatively constant ratio, yet taxa with the highest abundance level tend to be ephemeral. More than 90% of classified metagenomes were Gammaproteobacteria, Bacilli and Actinobacteria genetic signatures. Jaccard dissimilarity between samples based on bacteria genus classifications hesitate from 0.63 to 0.77, which for shotgun sequencing indicates a high consistency in bacterial composition. Concurrently, we identified antagonistic relationships between certain bacterial clusters. The presence of genes related to antibiotic synthesis and antibiotic resistance suggests potential mechanisms underlying the stability of comb microbiomes. Differences between pupal and larval combs emerge in the total metagenome, while taxa with the highest abundance remained consistent. All this suggests that a key role in the functioning of the comb microbiome is played by minor biodiversity, the function of which remains to be established experimentally.

Genomic Analysis of a Novel Heavy Metal Resistant Isolate from a Black Sea Contaminated Sediment with the Potential to Degrade Alkanes: Plantactinospora alkalitolerans sp. nov

Microorganisms that grow in poorly studied environments are of special interest when new biotechnological applications are searched. The Melet river offshore sediments at the Black Sea have been described to contain an important number of contaminants from upstream industries which have been accumulating for years. Bacteria of such habitats must be adapted to the presence of those compounds and in some cases, are able to use them as carbon sources. In the analysis of some samples recovered from this environment, an actinobacterial strain was isolated, named as S1510T, and its taxonomic position was determined using a combination of phenotypic and genotypic properties. Strain S1510T presented phenotypic properties typical of members of the family Micromonosporaceae and was assigned to the Plantactinospora genus, based on the phylogenetic analyses of the 16S rRNA gene and whole-genome sequences. Low dDDH (digital DNA-DNA hybridization) values with other members of the genus confirmed that Plantactinospora sp. S1510T represents a novel species, and is proposed with the new name Plantactinospora alkalitolerans. The strain presented characteristics not previously described for other species in the genus, such as its high tolerance to alkaline pHs, the presence of genes related to the production and degradation of alkanes (oleABCD, ssuAD, almA), the degradation of several aromatic compounds, and the tolerance to high heavy metal concentrations. In addition, Plantactinospora sp. S1510T presents several bioclusters to produce nonribosomal peptide-synthetases, terpenes, polyketide synthases, and bacteriocins, that possess low similarities with known compounds.

Isolation, plant growth-promoting traits, antagonistic effects on clinical and plant pathogenic organisms and identification of actinomycetes from olive rhizosphere

Soil actinomycetes are a highly common group of bacteria and frequently studied as having secondary metabolites in the potential of producing the most preferred antagonistic content. Considering the continuous variation in soil structure, there is a potential for encountering different organisms. Almost all of antibiotic contents are produced by these bacteria and their importance increase. In this study, eleven different actinomycetes strain were isolated from the rhizosphere of olive trees investigated for their plant growth-promoting (PGP) traits including ammonia production, indole-3-acetic acid production, phosphate solubilization, and siderophore production with antagonistic activities against a set of pathogenic bacteria, fungi, and yeasts. All actinomycetes were identified according to 16S rRNA regions were recognized in four different Streptomyces species but according to fatty acid analysis, there would be at least six different organisms. The potential for antagonistic and plant growth-promoting traits of olive tree rhizosphere actinomycetes were a promising tool for agricultural applications and clinical antibiotic resistance. Differentiation of organisms with the antagonism of pathogenic activities and PGP features could be a definitive method for future studies.