Pseudomonas glareae sp. nov., a marine sediment-derived bacterium with antagonistic activity

Infestation of Rice by Gall Midge Influences Density and Diversity of Pseudomonas and Wolbachia in the Host Plant Microbiome

Background: The virulence of phytophagous insects is predominantly determined by their ability to evade or suppress host defense for their survival. The rice gall midge (GM, Orseolia oryzae), a monophagous pest of rice, elicits a host defense similar to the one elicited upon pathogen attack. This could be due to the GM feeding behaviour, wherein the GM endosymbionts are transferred to the host plant via oral secretions, and as a result, the host mounts an appropriate defense response(s) (i.e., up-regulation of the salicylic acid pathway) against these endosymbionts. Methods: The current study aimed to analyze the microbiome present at the feeding site of GM maggots to determine the exchange of bacterial species between GM and its host and to elucidate their role in rice-GM interaction using a next-generation sequencing approach. Results: Our results revealed differential representation of the phylum Proteobacteria in the GM-infested and -uninfested rice tissues. Furthermore, analysis of the species diversity of Pseudomonas and Wolbachia supergroups at the feeding sites indicated the exchange of bacterial species between GM and its host upon infestation. Conclusion: As rice-GM microbial associations remain relatively unstudied, these findings not only add to our current understanding of microbe-assisted insect-plant interactions but also provide valuable insights into how these bacteria drive insect-plant coevolution. Moreover, to the best of our knowledge, this is the first report analyzing the microbiome of a host plant (rice) at the feeding site of its insect pest (GM).

Shifts in Pseudomonas species diversity influence adaptation of brown planthopper to changing climates and geographical locations

The brown planthopper (BPH) is a monophagous sap-sucking pest of rice that causes immense yield loss. The rapid build-up of pesticide resistance combined with the ability of BPH populations to quickly overcome host plant resistance has rendered conventional control strategies ineffective. One of the likely ways in which BPH adapts to novel environments is by undergoing rapid shifts in its microbiome composition. To elucidate the rapid adaptation to novel environments and the contributions of Pseudomonas toward insect survival, we performed Pseudomonas-specific 16S rRNA gut-microbiome profiling of BPH populations. Results revealed the differential occurrence of Pseudomonas species in BPH populations with changing climates and geographical locations. Further, the observed variation in Pseudomonas species composition and abundance correlated with BPH survivability. Collectively, this study, while adding to our current understanding of symbiont-mediated insect adaptation, also demonstrated a complex interplay between insect physiology and microbiome dynamics, which likely confers BPH its rapid adaptive capacity.

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BPH, a major pest of rice, undergoes seasonal shifts in its microbiome composition

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Pseudomonas sp. in BPH microbiome varied with seasons and geographical locations

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Pseudomonas sp. composition and abundance correlated with BPH survivability

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Environment-guided microbial shifts drive rapid stress adaptations in BPH

Alginate and fucoidan changes the bacterial community in different directions and the alginate or fucoidan degrading bacteria isolated from paddy soil promotes the plant growth

Seaweed and its extracts have been developed as fertilizers because they possess plant-growth-promoting and antibacterial compounds. For use as fertilizers, the major carbohydrates in seaweed, including fucoidan and alginate, need to be efficiently digested in the soil. We isolated fucoidan/alginate degrading bacteria from paddy soil and verified its use as a biofertilizer. Results show that Stenotrophomonas pavanii has a high alginate degrading activity, and also stimulating melon, pepper, and tomato growth. The growth stimulation effect of the bacteria was enhanced by alginate treatment. Bacillus sp. was isolated as a fucoidan degrading bacterium and this bacterium was also able to stimulate melon growth. Using 16S ribosomal DNA analysis, fucoidan/alginate resistant or susceptible bacteria were successively selected. Bacteria with increased population due to fucoidan and alginate had specificity to each carbohydrate, whereas those with decreased population showed susceptibility to both carbohydrates. This report demonstrates some bacteria for their use as biofertilizers with seaweed and demonstrated that a high throughput method is efficient in identifying bacteria with specific properties.

Biochemical and Genomic Characterization of the Cypermethrin-Degrading and Biosurfactant-Producing Bacterial Strains Isolated from Marine Sediments of the Chilean Northern Patagonia

Pesticides cause severe environmental damage to marine ecosystems. In the last ten years, cypermethrin has been extensively used as an antiparasitic pesticide in the salmon farming industry located in Northern Patagonia. The objective of this study was the biochemical and genomic characterization of cypermethrin-degrading and biosurfactant-producing bacterial strains isolated from cypermethrin-contaminated marine sediment samples collected in southern Chile (MS). Eleven strains were isolated by cypermethrin enrichment culture techniques and were identified by 16S rDNA gene sequencing analyses. The highest growth rate on cypermethrin was observed in four isolates (MS13, MS15a, MS16, and MS19) that also exhibited high levels of biosurfactant production. Genome sequence analyses of these isolates revealed the presence of genes encoding components of bacterial secondary metabolism, and the enzymes esterase, pyrethroid hydrolase, and laccase, which have been associated with different biodegradation pathways of cypermethrin. These novel cypermethrin-degrading and biosurfactant-producing bacterial isolates have a biotechnological potential for biodegradation of cypermethrin-contaminated marine sediments, and their genomes contribute to the understanding of microbial lifestyles in these extreme environments.

The biotechnological potential of marine bacteria in the novel lineage of Pseudomonas pertucinogena

Marine habitats represent a prolific source for molecules of biotechnological interest. In particular, marine bacteria have attracted attention and were successfully exploited for industrial applications. Recently, a group of Pseudomonas species isolated from extreme habitats or living in association with algae or sponges were clustered in the newly established Pseudomonas pertucinogena lineage. Remarkably for the predominantly terrestrial genus Pseudomonas, more than half (9) of currently 16 species within this lineage were isolated from marine or saline habitats. Unlike other Pseudomonas species, they seem to have in common a highly specialized metabolism. Furthermore, the marine members apparently possess the capacity to produce biomolecules of biotechnological interest (e.g. dehalogenases, polyester hydrolases, transaminases). Here, we summarize the knowledge regarding the enzymatic endowment of the marine Pseudomonas pertucinogena bacteria and report on a genomic analysis focusing on the presence of genes encoding esterases, dehalogenases, transaminases and secondary metabolites including carbon storage compounds.

The current status on the taxonomy of Pseudomonas revisited: An update

The genus Pseudomonas described in 1894 is one of the most diverse and ubiquitous bacterial genera which encompass species isolated worldwide. In the last years more than 70 new species have been described, which were isolated from different environments, including soil, water, sediments, air, animals, plants, fungi, algae, compost, human and animal related sources. Some of these species have been isolated in extreme environments, such as Antarctica or Atacama desert, and from contaminated water or soil. Also, some species recently described are plant or animal pathogens. In this review, we revised the current status of the taxonomy of genus Pseudomonas and the methodologies currently used for the description of novel species which includes, in addition to the classic ones, new methodologies such as MALDI-TOF MS, MLSA and genome analyses. The novel Pseudomonas species described in the last years are listed, together with the available genome sequences of the type strains of Pseudomonas species present in different databases.

List of new names and new combinations previously effectively, but not validly, published

The purpose of this announcement is to effect the valid publication of the following effectively published new names and new combinations under the procedure described in the Bacteriological Code (1990 Revision). Authors and other individuals wishing to have new names and/or combinations included in future lists should send three copies of the pertinent reprint or photocopies thereof, or an electronic copy of the published paper to the IJSEM Editorial Office for confirmation that all of the other requirements for valid publication have been met. It is also a requirement of IJSEM and the ICSP that authors of new species, new subspecies and new combinations provide evidence that types are deposited in two recognized culture collections in two different countries. It should be noted that the date of valid publication of these new names and combinations is the date of publication of this list, not the date of the original publication of the names and combinations. The authors of the new names and combinations are as given below. Inclusion of a name on these lists validates the publication of the name and thereby makes it available in the nomenclature of prokaryotes. The inclusion of a name on this list is not to be construed as taxonomic acceptance of the taxon to which the name is applied. Indeed, some of these names may, in time, be shown to be synonyms, or the organisms may be transferred to another genus, thus necessitating the creation of a new combination.