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Recent advancements in semiconductor technologies have stimulated the growth of ultra-low power wearable devices. However, these devices often pose critical constraints in usability and functionality because of the on-device battery as the primary power source [1]. For example, periodic charging of wearable devices hampers the continuous monitoring of users' fitness or health conditions [2], and batteries and charging equipment have been identified as one of the most rapidly growing electronic waste streams [3]. To counteract the above-mentioned complications associated with the management of on-device batteries, wireless power transmission technologies capable of charging wearable devices in a completely unobtrusive and seamless manner have become an emerging topic of research over the past decade [4]. Researchers have instrumented daily objects or the surrounding environment with equipment that can wirelessly transfer energy from a variety of sources, such as Radio Frequency (RF) signals, laser, and electromagnetic fields [5]. However, these solutions require large and costly infrastructure and/or need to transmit a significant amount of power to support reasonable power harvesting at the wearable devices, which conflict with the vision of ubiquitously available and scalable charging support.

Plasmids drive bacterial evolutionary innovation by transferring ecologically important functions between lineages, but acquiring a plasmid often comes at a fitness cost to the host cell. Compensatory mutations, which ameliorate the cost of plasmid carriage, promote plasmid maintenance in simplified laboratory media across diverse plasmid-host associations. Whether such compensatory evolution can occur in more complex communities inhabiting natural environmental niches where evolutionary paths may be more constrained is, however, unclear. Here we show a substantial fitness cost of carrying the large conjugative plasmid pQBR103 in Pseudomonas fluorescens in the plant rhizosphere. This plasmid fitness cost could be ameliorated by compensatory mutations affecting the chromosomal global regulatory system gacA/gacS, which arose rapidly in plant rhizosphere communities and were exclusive to plasmid carriers. These findings expand our understanding of the importance of compensatory evolution in plasmid dynamics beyond simplified lab media. Compensatory mutations contribute to plasmid survival in bacterial populations living within complex microbial communities in their natural environmental niche.

Many strains of Pseudomonas colonise plant surfaces, including the cherry canker pathogens, Pseudomonas syringae pathovars syringae and morsprunorum. We have examined the genomic diversity of P. syringae in the cherry phyllosphere and focused on the role of prophages in transfer of genes encoding Type 3 secreted effector (T3SE) proteins contributing to the evolution of virulence. Phylogenomic analysis was carried out on epiphytic pseudomonads in the UK orchards. Significant differences in epiphytic populations occurred between regions. Nonpathogenic strains were found to contain reservoirs of T3SE genes. Members of P. syringae phylogroups 4 and 10 were identified for the first time from Prunus. Using bioinformatics, we explored the presence of the gene encoding T3SE HopAR1 within related prophage sequences in diverse P. syringae strains including cherry epiphytes and pathogens. Results indicated that horizontal gene transfer (HGT) of this effector between phylogroups may have involved phage. Prophages containing hopAR1 were demonstrated to excise, circularise and transfer the gene on the leaf surface. The phyllosphere provides a dynamic environment for prophage-mediated gene exchange and the potential for the emergence of new more virulent pathotypes. Our results suggest that genome-based epidemiological surveillance of environmental populations will allow the timely application of control measures to prevent damaging diseases.

Point-of-care ultrasound has become an integral aspect of critical care training. The Bedside Assessment by Sonography In Critical Care Medicine Curriculum was established at the University of Toronto to train critical care trainees in basic echocardiography and general critical care ultrasound. During the coronavirus disease (COVID-19) pandemic, our program needed to adapt quickly to ensure staff safety and adherence to infection-control protocols. In this article, we share our experience and reflect on the challenges and benefits of shifting from a primarily in-person teaching model to a hybrid model of remote and in-person teaching. Curricular changes were threefold: the transition to entirely web-based interactive didactic teaching and online imaging interpretation modules, the recruitment of sonographers at multiple academic sites as instructors to facilitate in-person practices with lower instructor to trainee ratio, and the use of a mobile application for informal group case-based discussions. Challenges included lost opportunities for scanning healthy volunteers, variability in attendance at online lectures, and a lower number of study submissions for review. However, curricular changes enabled maintenance of directly observed practice, high levels of engagement with recorded content, and an expansion of our reach to a global audience. We believe that future curricula should combine high-quality online curriculum and resources with the ongoing in-person delivery of key elements of curriculum to allow for direct observation and feedback as well as the maintenance of self-directed point-of-care ultrasound portfolios.

Beyond their role in horizontal gene transfer, conjugative plasmids commonly encode homologues of bacterial regulators. Known plasmid regulator homologues have highly targeted effects upon the transcription of specific bacterial traits. Here, we characterise a plasmid translational regulator, RsmQ, capable of taking global regulatory control in Pseudomonas fluorescens and causing a behavioural switch from motile to sessile lifestyle. RsmQ acts as a global regulator controlling the host proteome through direct interaction with host mRNAs and interference with the host’s translational regulatory network. This mRNA interference leads to largescale proteomic changes in metabolic genes, key regulators and genes involved in chemotaxis, thus controlling bacterial metabolism and motility. Moreover, comparative analyses found RsmQ on a large number of divergent plasmids isolated from multiple bacterial host taxa, suggesting the widespread importance of RsmQ for manipulating bacterial behaviour across clinical, environmental, and agricultural niches. RsmQ is a widespread plasmid global translational regulator primarily evolved for host chromosomal control to manipulate bacterial behaviour and lifestyle.Significance StatementPlasmids are recognised for their important role in bacterial evolution as drivers of horizontal gene transfer. Less well understood are the effects of plasmids upon bacterial behaviours by manipulating the expression of key bacterial phenotypes. Until now, examples of plasmid manipulation of their bacterial hosts were limited to highly targeted transcriptional control of a few related traits. In contrast, here we describe the first plasmid global translational regulator evolved to control the bacterial behavioural switch from a motile to a sessile lifestyle and bacterial metabolism, mediated through manipulation of the bacterial proteome. Moreover, this global translational regulator is common across divergent plasmids in a wide range of bacterial host taxa, suggesting that plasmids may commonly control bacterial lifestyle in the clinic, agricultural fields, and beyond.

Fluorescent pseudomonads represent one of the largest groups of bacteria inhabiting the surfaces of plants, but their genetic composition in planta is poorly understood. Here, we examined the population structure and diversity of fluorescent pseudomonads isolated from sugar beet grown at two geographic locations (Oxford, United Kingdom and Auckland, New Zealand). To seek evidence for niche adaptation, bacteria were sampled from three types of leaves (immature, mature, and senescent) and then characterized using a combination of genotypic and phenotypic analysis. We first performed multilocus sequence analysis (MLSA) of three housekeeping genes (gapA, gltA, and acnB) in a total of 152 isolates (96 from Oxford, 56 from Auckland). The concatenated sequences were grouped into 81 sequence types and 22 distinct operational taxonomic units (OTUs). Significant levels of recombination were detected, particularly for the Oxford isolates (rate of recombination to mutation (r/m) = 5.23 for the whole population). Subsequent ancestral analysis performed in STRUCTURE found evidence of six ancestral populations, and their distributions significantly differed between Oxford and Auckland. Next, their ability to grow on 95 carbon sources was assessed using the Biolog™ GN2 microtiter plates. A distance matrix was generated from the raw growth data (A660) and subjected to multidimensional scaling (MDS) analysis. There was a significant correlation between substrate utilization profiles and MLSA genotypes. Both phenotypic and genotypic analyses indicated presence of a geographic structure for strains from Oxford and Auckland. Significant differences were also detected for MLSA genotypes between strains isolated from immature versus mature/senescent leaves. The fluorescent pseudomonads thus showed an ecotypic population structure, suggestive of adaptation to both geographic conditions and local plant niches.

Bacterial canker disease is a major limiting factor in the growing of cherry and other Prunus species worldwide. At least five distinct clades within the bacterial species complex Pseudomonas syringae are known to be causal agents of the disease. The different pathogens commonly coexist in the field. Reducing canker is a challenging prospect as the efficacy of chemical controls and host resistance may vary against each of the diverse clades involved. Genomic analysis has revealed that the pathogens use a variable repertoire of virulence factors to cause the disease. Significantly, strains of P. syringae pv. syringae possess more genes for toxin biosynthesis and fewer encoding type III effector proteins. There is also a shared pool of key effector genes present on mobile elements such as plasmids and prophages that may have roles in virulence. By contrast, there is evidence that absence or truncation of certain effector genes, such as hopAB, is characteristic of cherry pathogens. Here we highlight how recent research, underpinned by the earlier epidemiological studies, is allowing significant progress in our understanding of the canker pathogens. This fundamental knowledge, combined with emerging insights into host genetics, provides the groundwork for development of precise control measures and informed approaches to breed for disease resistance., A review of Pseudomonas cherry canker linking genomics to control.

Plants have proficient tools that allow them to survive interactions with pathogens. Upon attack, they respond with specific countermeasures, which are controlled by the immune system. However, defences can fail and this failure exposes plants to fast-spreading devastation. Trees face similar challenges to other plants and their immune system allows them to mount defences against pathogens. However, their slow growth, longevity, woodiness, and size can make trees a challenging system to study. Here, we review scientific successes in plant systems, highlight the key challenges and describe the enormous opportunities for pathology research in trees. We discuss the benefits that scaling-up our understanding on tree-pathogen interactions can provide in the fight against plant pathogenic threats.

Bacterial canker is a major disease of stone fruits and is a critical limiting factor to sweet cherry ( ) production worldwide. One important strategy for disease control is the development of resistant varieties. Partial varietal resistance in sweet cherry is discernible using shoot or whole tree inoculations; however, these quantitative differences in resistance are not evident in detached leaf assays. To identify novel sources of resistance to canker, we used a rapid leaf pathogenicity test to screen a range of wild cherry, ornamental species and sweet cherry × ornamental cherry hybrids with the canker pathogens, pvs , races 1 and 2, and . Several accessions exhibited limited symptom development following inoculation with each of the pathogens, and this resistance extended to 16 . strains pathogenic on sweet cherry and plum. Resistance was associated with reduced bacterial multiplication after inoculation, a phenotype similar to that of commercial sweet cherry towards nonhost strains of . . Progeny resulting from a cross of a resistant ornamental species with susceptible sweet cherry ( . ) exhibited resistance indicating it is an inherited trait. Identification of accessions with resistance to the major bacterial canker pathogens is the first step towards characterizing the underlying genetic mechanisms of resistance and introducing these traits into commercial germplasm. [Abstract copyright: © 2021 The Authors. Plant Pathology published by John Wiley & Sons Ltd on behalf of British Society for Plant Pathology.]

Beyond their role in horizontal gene transfer, conjugative plasmids commonly encode homologues of bacterial regulators. Known plasmid regulator homologues have highly targeted effects upon the transcription of specific bacterial traits. Here, we characterise a plasmid translational regulator, RsmQ, capable of taking global regulatory control in Pseudomonas fluorescens and causing a behavioural switch from motile to sessile lifestyle. RsmQ acts as a global regulator, controlling the host proteome through direct interaction with host mRNAs and interference with the host’s translational regulatory network. This mRNA interference leads to large-scale proteomic changes in metabolic genes, key regulators, and genes involved in chemotaxis, thus controlling bacterial metabolism and motility. Moreover, comparative analyses found RsmQ to be encoded on a large number of divergent plasmids isolated from multiple bacterial host taxa, suggesting the widespread importance of RsmQ for manipulating bacterial behaviour across clinical, environmental, and agricultural niches. RsmQ is a widespread plasmid global translational regulator primarily evolved for host chromosomal control to manipulate bacterial behaviour and lifestyle.

Moko disease, caused by the bacterium Ralstonia solanacearum, is one of the most devastating diseases of Musa spp. in Colombia, where banana and plantain are major crops. The disease epidemiology is poorly understood and little is known about the diversity of the bacterial populations associated with this disease. This study assessed the diversity, phylogenetic relationship and pathogenicity of R. solanacearum strains associated with moko disease in Colombia. For this, the genetic diversity of 65 isolates obtained from four banana/plantain‐growing regions was evaluated by using multiplex PCR and analysing the partial sequences of the mutS, rplB and egl genes. These analyses revealed that all the strains belonged to the R. solanacearum phylotype II, sequevars 4 and 6. In addition, the phylogenetic analysis assorted the strains into three subgroups, which matched the region of isolation: (i) central region (i.e. Eastern plains and Andes, IIB/4); (ii) northwest (i.e. Uraba and a few strains from Magdalena, IIB/4); and (iii) north coast (Magdalena and a few strains from Uraba, IIA/6). In addition, this evolutionary pattern was associated with pathogenicity, as 63 of the 65 isolates caused wilting of banana and plantain plants under greenhouse conditions, whilst only 32, those isolated from the central region, caused such symptoms in tomato plants. In conclusion, this study shows that banana and plantain crops in Colombia foster genetically diverse strains of R. solanacearum that belong to at least three different genetic groups, which show biogeographic and host range association.

Arabinose is a major plant aldopentose in the form of arabinans complexed in cell wall polysaccharides or glycoproteins (AGP), but comparatively rare as a monosaccharide. l-arabinose is an important bacterial metabolite, accessed by pectolytic micro-organisms such as Pectobacterium atrosepticum via pectin and hemicellulose degrading enzymes. However, not all plant-associated microbes encode cell-wall-degrading enzymes, yet can metabolize l-arabinose, raising questions about their use of and access to the glycan in plants. Therefore, we examined l-arabinose metabolism in the food-borne pathogen Escherichia coli O157:H7 (isolate Sakai) during its colonization of plants. l-arabinose metabolism (araBA) and transport (araF) genes were activated at 18 °C in vitro by l-arabinose and expressed over prolonged periods in planta. Although deletion of araBAD did not impact the colonization ability of E. coli O157:H7 (Sakai) on spinach and lettuce plants (both associated with STEC outbreaks), araA was induced on exposure to spinach cell-wall polysaccharides. Furthermore, debranched and arabinan oligosaccharides induced ara metabolism gene expression in vitro, and stimulated modest proliferation, while immobilized pectin did not. Thus, E. coli O157:H7 (Sakai) can utilize pectin/AGP-derived l-arabinose as a metabolite. Furthermore, it differs fundamentally in ara gene organization, transport and regulation from the related pectinolytic species P. atrosepticum , reflective of distinct plant-associated lifestyles.

Bacterial canker is a major disease of stone fruits and is a critical limiting factor to sweet cherry (

At the level of the gene, mutation is the raw material for natural selection. However, at the level of the gene regulatory network (GRN), variation is revealed to selection via promiscuous regulator activity ('crosstalk'), which creates opportunities for genetic innovation that can facilitate adaptation. Many genetic and environmental features can contribute to increasing potential for crosstalk by facilitating non-cognate interactions between regulatory elements. If a novel interaction provides a fitness benefit, rewired GRNs with strengthened affinity for newly forged connections can be selected. Here, we identify factors that facilitate opportunities for crosstalk and rewiring between GRNs, consider whether features of some GRNs make them more 'rewireable' than others and if these features might constrain evolution towards convergent outcomes. We explore patterns from laboratory and natural microbial populations that show changes within GRNs during adaptation. Finally, we discuss the prospects and open questions in the field.

Bacterial canker of Prunus, affecting economically important stone fruit crops including cherry, peach, apricot and plum, is caused by the plant pathogen Pseudomonas syringae (P.s.). Strains from two pathovars—P.s. pv. syringae (Pss) and P.s. pv. morsprunorum race 1 (PsmR1) and 2 (PsmR2)—in three phylogenetically distant clades have convergently evolved to infect Prunus. The bacteria enter woody tissues through wounds and leaf scars, causing black necrotic cankers. Symptoms are also produced on blossom, fruit and leaves. Little is known about the mechanisms P.s. uses to colonise tree hosts such as Prunus. Here, we created transposon (Tn) mutant libraries in one strain of P.s. from each of the three clades and screened the mutants on immature cherry fruit to look for changes in virulence. Mutants (242) with either reduced or enhanced virulence were detected and further characterised by in vitro screens for biofilm formation, swarming ability, and pathogenicity on leaves and cut shoots. In total, 18 genes affecting virulence were selected, and these were involved in diverse functions including motility, type III secretion, membrane transport, amino acid synthesis, DNA repair and primary metabolism. Interestingly, mutation of the effector gene, hopAU1, led to an increase in virulence of Psm R2.

International audience; Aphids, including the peach-potato aphid, Myzus persicae, are major insect pests of agriculture and horticulture, and aphid control measures are limited. There is therefore an urgent need to develop alternative and more sustainable means of control. Recent studies have shown that environmental microbes have varying abilities to kill insects. We screened a range of environmental bacteria isolates for their abilities to kill target aphid species. Tests demonstrated the killing aptitude of these bacteria against six aphid genera (including Myzus persicae). No single bacterial strain was identified that was consistently toxic to insecticide-resistant aphid clones than susceptible clones, suggesting resistance to chemicals is not strongly correlated with bacterial challenge. Pseudomonas fluorescens PpR24 proved the most toxic to almost all aphid clones whilst exhibiting the ability to survive for over three weeks on three plant species at populations of 5–6 log CFU cm−2 leaf. Application of PpR24 to plants immediately prior to introducing aphids onto the plants led to a 68%, 57% and 69% reduction in aphid populations, after 21 days, on Capsicum annuum, Arabidopsis thaliana and Beta vulgaris respectively. Together, these findings provide new insights into aphid susceptibility to bacterial infection with the aim of utilizing bacteria as effective biocontrol agents.

Bacterial diseases of the edible white button mushroom Agaricus bisporus caused by Pseudomonas species cause a reduction in crop yield, resulting in considerable economic loss. We examined bacterial pathogens of mushrooms and bacteriophages that target them to understand the disease and opportunities for control. The Pseudomonastolaasii genome encoded a single type III protein secretion system (T3SS), but contained the largest number of non-ribosomal peptide synthase (NRPS) genes, multimodular enzymes that can play a role in pathogenicity, including a putative tolaasin-producing gene cluster, a toxin causing blotch disease symptom. However, Pseudomonasagarici encoded the lowest number of NRPS and three putative T3SS while non-pathogenic Pseudomonas sp. NS1 had intermediate numbers. Potential bacteriophage resistance mechanisms were identified in all three strains, but only P. agarici NCPPB 2472 was observed to have a single Type I-F CRISPR/Cas system predicted to be involved in phage resistance. Three novel bacteriophages, NV1, ϕNV3, and NV6, were isolated from environmental samples. Bacteriophage NV1 and ϕNV3 had a narrow host range for specific mushroom pathogens, whereas phage NV6 was able to infect both mushroom pathogens. ϕNV3 and NV6 genomes were almost identical and differentiated within their T7-like tail fiber protein, indicating this is likely the major host specificity determinant. Our findings provide the foundations for future comparative analyses to study mushroom disease and phage resistance.

Bleeding canker of horse chestnut trees is a bacterial disease, caused by the bacterium Pseudomonas syringae pv. aesculi, estimated to be present in ~ 50% of UK horse chestnut trees. Currently, the disease has no cure and tree removal can be a common method of reducing inoculum and preventing spread. One potential method of control could be achieved using naturally occurring bacteriophages infective to the causative bacterium. Bacteriophages were isolated from symptomatic and asymptomatic horse chestnut trees in three locations in the South East of England. The phages were found to be belonging to both the Myoviridae and Podoviridae families by RAPD PCR and transmission electron microscopy. Experimental coevolution was carried out to understand the dynamics of bacterial resistance and phage infection and to determine whether new infective phage genotypes would emerge. The phages exhibited different coevolution patterns with their bacterial hosts across time. This approach could be used to generate novel phages for use in biocontrol cocktails in an effort to reduce the potential emergence of bacterial resistance. Electronic supplementary material The online version of this article (10.1007/s00284-020-01952-1) contains supplementary material, which is available to authorized users.