Original Host Research Articles

Genetic characterization of Trichomonas gallinae (Rivolta, 1878) in companion birds in Japan and the genotypical relationship in the Asia region.

Avian trichomonosis is a parasitic infection that affects a wide range of avian species, including free-ranging and pet birds worldwide, and Trichomonas gallinae has been considered as the only causative agent for decades. The sequence of the 5.8S ribosomal RNA with internal transcribed spacer (ITS) regions was widely used for identifying genotypes and determining inter-specific and intra-specific diversity. Moreover, the sequence of Fe-hydrogenase (FeHyd) was proposed as the second genetic marker for providing improved resolution of strain subtyping discrimination. Though the correlation between genetic variability and strain virulence is controversial, FeHyd analyses seemed to be useful to investigate the host or geographic origin of isolates. This study aimed to investigate the genetic characteristics of avian Trichomonas spp. Forty-seven oral swabs and crop lavage fluids were collected from 9 avian genera, which were diagnosed as Trichomonas-positive by microscopy in animal hospitals in Japan, were analyzed. Genetic analysis of clonal isolates revealed the prevalence of the single genotype, ITS-OBT-Tg-1, by ITS region analysis, while two different subtypes, A2 and novel A3, were suggested by FeHyd gene analysis among Japanese companion birds. Phylogenetic analyses of available ITS sequences obtained from the Asia region (China, Iran, Iraq, and Saudi Arabia) were also preformed, revealing endemic ITS-OBT-Tg-1, ITS-OBT-Tg-2, ITS-OBT-Ttl-1, genotype III, and Saudi Arabia's unique lineages. Furthermore, ITS-OBT-Tg-2 predominance in these countries indicates different strains origination from Japan. This is the first report of the genetic characterization of T. gallinae in Japan with discovery of novel subtype A3.

First description of a multisystemic and lethal SARS-CoV-2 variant of concern P.1 (Gamma) infection in a FeLV-positive cat

BackgroundPhylogenetic studies indicate bats as original hosts of SARS-CoV-2. However, it remains unclear whether other animals, including pets, are crucial in the spread and maintenance of COVID-19 worldwide.MethodsIn this study, we analyzed the first fatal case of a SARS-CoV-2 and FeLV co-infection in an eight-year-old male cat. We carried out a clinical evaluation and several laboratory analyses.ResultsAs main results, we observed an animal presenting severe acute respiratory syndrome and lesions in several organs, which led to the animal’s death. RT-qPCR analysis showed a SARS-CoV-2 as the causative agent. The virus was detected in several organs, indicating a multisystemic infection. The virus was found in a high load in the trachea, suggesting that the animal may have contribute to the transmission of the virus. The whole-genome sequencing revealed an infection by SARS-CoV-2 Gamma VOC (P.1), and any mutations indicating host adaptation were observed.ConclusionOur data show that FeLV-positive cats are susceptible to SARS-CoV-2 infection and raise questions about the potential of immunocompromised FeLV-positive cats to act as a reservoir for SARS-CoV-2 new variants.

In vitro functional characterization predicts the impact of bacterial root endophytes on plant growth.

Utilizing beneficial microbes for crop improvement is one strategy to achieve sustainable agriculture. However, identifying microbial isolates that promote crop growth is challenging, in part because using bacterial taxonomy to predict an isolate's effect on plant growth may not be reliable. The overall aim of this work was to determine whether in vitro functional traits of bacteria were predictive of their in planta impact. We isolated 183 bacterial endophytes from field-grown roots of two tomato species, Solanum lycopersicum and S. pimpinellifolium. Sixty isolates were screened for six in vitro functional traits: auxin production, siderophore production, phosphate solubilization, antagonism to a soilborne pathogen, and the presence of two antimicrobial metabolite synthesis genes. Hierarchical clustering of the isolates based on the in vitro functional traits identified several groups of isolates sharing similar traits. We called these groups 'functional groups'. To understand how in vitro functional traits of bacteria relate to their impact on plants, we inoculated three isolates from each of the functional groups on tomato seedlings. Isolates within the same functional group promoted plant growth at similar levels, regardless of their host origin or taxonomy. Together, our results demonstrate the importance of examining root endophyte functions for improving crop production.

Inducing Tolerance to Abiotic Stress in Hordeum vulgare L. by Halotolerant Endophytic Fungi Associated With Salt Lake Plants.

A characteristic trait of plants living in harsh environments is their association with fungal endophytes, which enable them to survive under extreme stress. Abiotic stress resistance in agro-ecosystems, particularly in arid and semi-arid regions, can be increased by inoculating these fungal endophytes on plants other than their original hosts. The present study is therefore focused on the possible role of three halotolerant endophytic fungi, i.e., Periconia macrospinosa, Neocamarosporium goegapense, and N. chichastianum, isolated from roots of salt lake plants growing in the central desert of Iran, in alleviating the adverse effects of salinity and drought stresses on barley under greenhouse conditions. To perform this experiment, a randomized block design was applied with three factors: fungi (four levels including three halotolerant endophytic species and control), salinity (three levels including 8, 12, and 16 dS/m), and drought (four levels including 100, 80, 60, 40 percent field capacity). All plants were measured for growth characteristics, chlorophyll concentration, proline content, and antioxidant enzyme activities. A three-way analysis of variance indicated that all three fungal endophytes, to varying extents, induced the barley plants’ resistance to salinity and drought, and their combined effects. Additionally, we found that fungal endophytes were more effective when the barley plants were subjected to higher levels of salinity and drought. Under the stress of salinity and drought, a strong relationship between inoculation of fungal endophytes and enhancement of biomass, shoot length, chlorophyll concentration, proline content, and activity of catalase, peroxidase, and superoxide dismutase was indicated. We discussed that increased root growth, proline content, and antioxidant enzyme activity are the main physiological and biochemical mechanisms causing stress resistance in barley plants inoculated with endophytes. Our research findings illustrate that fungal endophytes have a substantial potential for increasing abiotic stress tolerance in barley plants, which can be applied in agricultural ecosystems.

Abstract A003: Genome evolution of a transmissible cancer in the soft-shell clam (Mya arenaria)

Abstract A small number of transmissible cancer lineages exist in which cancer cells metastasize repeatedly to new hosts and live past the death of their original hosts. Transmissible cancers have been observed in the dog, Tasmanian devil, and most recently in numerous bivalves species, including one lineage that has spread through the soft-shell clam (Mya arenaria) population along the east coast of North America. We assembled a highly contiguous 1.2 Gb soft-shell clam reference genome and characterized the genome evolution of this transmissible cancer lineage. Our analyses confirm that all cancer samples descended from a single founder clam, but cluster in two geographically separated sub-lineages. In both sub-lineages, we observe high somatic mutation density, widespread copy number gain, structural rearrangement and transposable element activity, all indicative an unstable cancer genome. We also discovered a novel mutational signature generating mutations at a stable rate, predicting the cancer to be 344 to 877 years old and indicating it spread undetected long before it was first observed in the 1970s. Citation Format: Samuel F.M. Hart, Rachael M. Giersch, Marisa A. Yonemitsu, Brian Beal, Stephen P. Goff, Michael J. Metzger. Genome evolution of a transmissible cancer in the soft-shell clam (Mya arenaria) [abstract]. In: Proceedings of the AACR Special Conference on the Evolutionary Dynamics in Carcinogenesis and Response to Therapy; 2022 Mar 14-17. Philadelphia (PA): AACR; Cancer Res 2022;82(10 Suppl):Abstract nr A003.

Dressing like a pathogen: Comparative analysis of different Pseudomonas genomospecies wearing different features to infect Corylus avellana

AbstractDuring the last decade, the European hazelnut (Corylus avellana) has been threatened by several bacterial and fungal infections. In particular, at least four different Pseudomonas species have developed the capability to converge into the same host. However, one of these species, Pseudomonas avellanae, may infect other hosts as well. Here, we newly provide the complete genome sequence of two Pseudomonas avellanae strains obtained by a combination of long Oxford Nanopore Technologies reads (ONT) and short Illumina reads. These have been included in a comparative analysis with all the genomes of Pseudomonas strains known to infect Corylus avellana available on the NCBI database, and the genomes of Pseudomonas avellanae strains infecting other host plants, like Prunus, Actinidia and from the river epilithon. The Pseudomonas strains clustered according to their taxonomy, host and geographic origins. The identification of specific traits related to each population cluster could give us insights regarding the host–pathogen interaction and the host range specificity. Indeed, the Pseudomonas avellanae strains infecting hazelnut have a peculiar set of three type III secretion effectors, while the Pseudomonas avellanae infecting Prunus and Actinidia are carrying the genomic WHOP island, necessary for woody‐host infection. The syringae cluster, instead, contains more phytotoxins, the ice nucleation cluster, but less effectors. Thus, here, we confirmed that the convergence into the same host was possible due to different unrelated mechanisms of infection.

Germanium redistribution during weathering of Zn mine wastes: Implications for environmental mobility and recovery of a critical mineral

Germanium (Ge) is a metal used in emerging energy technologies, communications, and defense, and has been deemed critical by the United States due to its essential applications and scarce supply. Germanium is recovered as a byproduct of zinc (Zn) sulfides, and mining and processing of these materials lead to waste that could act both as a source of extractable Ge and a source for exposure to humans and ecosystems. Yet the distribution, speciation, and mineral hosts of Ge in mining-impacted areas are poorly understood. The Tar Creek Superfund Site, a former Zn mining area and Ge producer, is a natural laboratory to understand the environmental behavior and economic implications of Ge in mine wastes. We studied the distribution and behavior of Ge in solid wastes at the Tar Creek Superfund Site using bulk and microanalytical techniques. In wastes at this site we find that Ge has been redistributed from its original host, sphalerite (ZnS), to the fine-grained weathering product hemimorphite (Zn4Si2O7(OH)2·H2O), which impacts germanium's mobility, bioaccessibility, and potential for recovery. We provide chemical and mineralogical evidence of this redistribution, along with an evaluation of the oxidation state and molecular-scale substitution of Ge into sphalerite, hemimorphite, and quartz. Geochemical modeling shows that hemimorphite is more stable than sphalerite in waste piles and provides a stable secondary repository for Ge. However, hemimorphite is fine-grained, and if ingested or inhaled is readily soluble, with the potential to release Ge. Lastly, we discuss other sites internationally where similar behavior may be important. This study shows that weathering can have a significant impact on the distribution, speciation, and mineral hosts of Ge in mine wastes; directly influence mobilization from waste piles and subsequent availability to humans and ecosystems; and dictate metallurgical strategies to target Ge for recovery.

Activation and Regulation of NLRP3 by Sterile and Infectious Insults.

Nod-Like Receptor (NLR) is the largest family of Pathogen Recognition Receptors (PRRs) that patrols the cytosolic environment. NLR engagement drives caspase-1 activation that cleaves pro-IL-1B which then gets secreted. Released IL-1B recruits immune cells to the site of infection/injury. Caspase-1 also cleaves Gasdermin-D (GSDM-D) that forms pores within the plasma membrane driving inflammatory cell death called pyroptosis. NLRP3 is the most extensively studied NLR. The NLRP3 gene is encoded by 9 exons, where exon 1 codes for pyrin domain, exon 3 codes for NACHT domain, and Leucine Rich Repeat (LRR) domain is coded by exon 4-9. Exon 2 codes for a highly disorganized loop that connects the rest of the protein to the pyrin domain and may be involved in NLRP3 regulation. The NLRP3 inflammasome is activated by many structurally divergent agonists of microbial, environmental, and host origin. Activated NLRP3 interacts with an adaptor protein, ASC, that bridges it to pro-Caspase-1 forming a multi-protein complex called inflammasome. Dysregulation of NLRP3 inflammasome activity is a hallmark of pathogenesis in several human diseases, indicating its highly significant clinical relevance. In this review, we summarize the existing knowledge about the mechanism of activation of NLRP3 and its regulation during activation by infectious and sterile triggers.

What's in a name? Taxonomic and gender biases in the etymology of new species names.

As our inventory of Earth's biodiversity progresses, the number of species given a Latin binomial name is also growing. While the coining of species names is bound by rules, the sources of inspiration used by taxonomists are an eclectic mix. We investigated naming trends for nearly 2900 new species of parasitic helminths described in the past two decades. Our analysis indicates that the likelihood of new species being given names that convey some information about them (name derived from morphology, host or locality of origin) or not (named after an eminent scientist, or for something else) depends on the higher taxonomic group to which the parasite or its host belongs. We also found a consistent gender bias among species named after eminent scientists, with male scientists being immortalized disproportionately more frequently than female scientists. Finally, we found that the tendency for taxonomists to name new species after a family member or close friend has increased over the past 20 years. We end by offering suggestions for future species naming, aimed at honouring the scientific community's diversity and avoiding etymological nepotism and cronyism, while still allowing for creativity in crafting new Latin species names.

Pythium and Phytopythium species associated with weeds collected in vegetable production fields in Brazil.

This study aimed to identify Pythium and Phytopythium species from weeds collected in vegetable fields and test their pathogenicity. Weeds with symptoms of damping-off, root rot or wilt were sampled in the Brazilian states of Ceará, Goiás and Pernambuco, as well as in the Distrito Federal, for isolation and identification of the causal agents. Once isolated, colonies with typical Pythium and Phytopythium characteristics grew in selective V8 medium. Procedures for species identification included morphology and amplification of the ITS and Cox II regions, which were compared with other accessions available at GenBank. The phylogenetic relationships among the isolates and pathogenicity to their original hosts were evaluated. Six Pythium species were identified: P. aphanidermatum, P. oopapillum, P. orthogonon, P. ultimum var. ultimum, P. myriotylum and P. sylvaticum, and two species of Phytopythium, Phy. chamaehyphon and Phy. oedochilum. In the pathogenicity tests, the 10 weed hosts showed symptoms of damping-off or root rot after inoculation, with exception of Portulaca oleraceae in which none of the isolates was pathogenic. Therefore, common weeds in vegetable fields areas can host different Pythium and Phytopythium species and play an important role in the epidemiology of vegetable diseases, in particular on pathogen survival and population increase.

Regulation of Transplanted Fetal Hepatocyte Proliferation by Histone Post‐Translational Modifications

IntroductionHepatic cell transplantation (HCT) offers a potential therapeutic alternative to orthotopic liver transplantation for end‐stage liver disease and could help relax the current reliance on scarce donor livers. While transplanted adult hepatocytes have shown a limited window of post‐transplant efficacy, fetal hepatocytes have been demonstrated to durably persist and proliferate in animal models and human clinical trials. Ethical procurement concerns prevent human fetal cells from being used in the clinic, making it important to characterize the mechanisms responsible for their growth advantage in order to activate this phenotype in adult hepatocytes or induced hepatocyte‐like cells. Our study examines histone post‐translational modification (hPTM) and gene expression profiles of fetal‐derived colonies and paired adult host tissue, compared to primary fetal and adult hepatocytes.MethodsPost‐transplant livers from our rat model were frozen, cryosectioned, and stained for fetal‐derived colonies. Sections of colony and host tissue from the same liver were collected using laser capture microdissection (LCM), and pre‐transplant adult and fetal rat hepatocytes were isolated or immunopurified using hepatic and ductal lineage markers. Histones were extracted from these tissue and cell samples for hPTM abundance quantification by mass spectrometry, and RNA was extracted for next‐gen sequencing. Data was analyzed using R, Gene Ontology (GO), and Ingenuity Pathway Analysis (IPA).Results13 PTMs of Histone H3 were found to have significantly different relative abundance between fetal‐derived colonies and host tissue as well as between fetal and adult hepatocytes, with the majority of marks having consistent abundance trends. RNA‐Seq expression profiles segregated the LCM samples by colony or host origin. Differential expression analysis found ≅1,000 significantly differentially expressed genes (DEGs) between colony and host tissue, and hundreds of these were found to also be similarly differentially expressed between fetal and adult hepatocytes. When analyzed by GO and IPA, the DEGs found to be expressed higher in fetal‐derived colonies revealed enrichment of ion transmembrane transport and calcium signaling pathways.ConclusionsFor at least 10 months following transplantation into an adult liver microenvironment, fetal‐hepatocyte‐derived colonies retain a distinct subset of both hPTM abundance and mRNA expression patterns in common with pre‐transplant fetal cells. These retained differences may drive the competitive growth advantage seen in fetal cells post‐transplant, and could potentially be harnessed to improve HCT outcomes. The differentially‐abundant hPTMs in colony tissue were all on Histone H3 and have known associations with gene transcription activity, and the colony DEGs reflect enrichment of biological processes associated with nutrient uptake, proliferation, and signaling. Our future work will explore the link between specific differentially expressed genes and the differentially abundant hPTMs that may be regulating them via ChIP‐Seq analysis of these histone marks.

Transnational Network and Information Flow in African Refugees and Undocumented Migrants’ International Migration Process

This paper analyses the role of information flow under transnational (social) networks to understand African refugees and undocumented migrants’ migration to Austria. Existing research pointed to the international refugee crisis with industrialised countries targeted border governance that has prompted the emergence of the transnational (social) network, which builds (kinship-based) connectivity and interchangeable acquaintances between migrants in host and country of origin to influence and facilitate migrants’ pre and post mobility process. However, the network often faces weak ties with exploitation and subjugation to human trafficking. Based on twenty qualitative problem-centred face-face interviews, data are collected and analysed with content analysis technique to fill in the gap. The findings indicate that pre-mobility guidance, directive, and legislative decoder regulatory tools influence transnational networks with a lack of well-managed network that may impair pre and post-mobility processes to shape African refugees and undocumented migrant international migratory pathways in an information flow setting. This study demonstrated actor-based network-driven advocacy governance. The outcome points to the strategic mobilization of collective information to resource vulnerable people and refugees or undocumented migrants to meet their needs. This is relevant to collective action in contemporary neoliberal society targeting freedom and movements that may not only constrain ethnic minority group mobility, but the universal human rights principles, public policy learning process, informal institution collaborative actions, and democratic values in times of crisis-related super-diversity societies.

A secondary metabolite drives intraspecies antagonism in a gut symbiont that is inhibited by cell-wall acetylation

The mammalian microbiome encodes numerous secondary metabolite biosynthetic gene clusters; yet, their role in microbe-microbe interactions is unclear. Here, we characterized two polyketide synthase gene clusters (fun and pks) in the gut symbiont Limosilactobacillus reuteri. The pks, but not the fun, cluster encodes antimicrobial activity. Forty-one of 51 L.reuteri strains tested are sensitive to Pks products; this finding was independent of strains' host origin. Sensitivity to Pks was also established in intraspecies competition experiments in gnotobiotic mice. Comparative genome analyses between Pks-resistant and -sensitive strains identified an acyltransferase gene (act) unique to Pks-resistant strains. Subsequent cell-wall analysis of wild-type and act mutant strains showed that Act acetylates cell-wall components, providing resistance to Pks-mediated killing. Additionally, pks mutants lost their competitive advantage, while act mutants lost their Pks resistance in invivo competition assays. These findings provide insight into how closely related gut symbionts can compete and co-exist in the gastrointestinal tract.

Meta-transcriptomic analysis reveals an isolate of aphid lethal paralysis virus from Wisteria sinensis in Iran

Viral metagenomic analysis of wisteria leaf sample in Iran detected one dicistrovirus: aphid lethal paralysis virus (ALPV). The complete genome sequence of ALPV-Ir-Wi was 9824 nucleotides (nt) in length (excluding the 3′-poly(A) tail), and contained two ORFs, an intergenic untranslated region of 197 nt flanked by a 538 nt 5′ UTR and a 576 nt 3′ UTR. Comparison with 21 other ALPV genomic sequences from different parts of the world revealed that it most closely resembled the Turkish and Israeli isolates. Pairwise identity analysis showed significant variability in genome sequences among ALPV isolates with genomic nucleotide identities of 78.35–99.15%. In addition to codon mutations, insertions/deletions and recombination also contributed to genetic variability. To explore the genetic variation and molecular evolution of ALPV, ORF2 gene sequences of 18 non-recombinant isolates were analyzed. The isolates belonged to two principal clades (FST=0.614) and showed a considerable genetic diversity (0.140±0.01). Most populations were polyphyletic, indicating that they had not been isolated long enough to reach reciprocal monophyly. There was no significant correlation between genetic and geographical distances or host origins. Pairwise FST and Nm values showed a meaningful differentiation and relatively infrequent gene flow between two compared populations (the Middle East vs. East Asia, the Middle East vs. Africa), and moderate gene flow for East Asian and African populations. Genes in the ALPV genome were subject to strong purifying selection during evolution, and most codons were under negative selection or neutral evolution. The results indicated a relatively stable and conserved genomic composition with a low codon usage bias in all of the assayed ALPV coding sequences. Recombination, natural selection, gene flow, and founder effects were found to be the main evolutionary factors that can affect the genetic structure of ALPV populations.

Thus spoke peptides: SARS-CoV-2 spike gene evolved in humans and then shortly in rats while the rest of its genome in horseshoe bats and then in treeshrews

ABSTRACT SARS-CoV-2 is suspected to be the product of a natural or artificial recombination of two viruses – one adapted to the horseshoe bat and the other, donor of the spike protein gene, adapted to an unknown species. Here we used a new method to search for the original host of the ancestor of the SARS-CoV-2 virus and for the donor of its gene for the spike protein, the molecule responsible for binding to and entering human cells. We computed immunological T-distances (the number of different peptides that are present in the viral proteins but absent in proteins of the host) between 11 species of coronaviruses and 38 representatives of the main mammal clades. Analyses of pentapeptides, the presumed principal targets of T-cell non-self recognition, showed the smallest T-distance of the spike protein of SARS-CoV-2 to humans, while the rest of SARS-CoV-2 proteome to the horseshoe bat. This suggests that the ancestor of SARS-CoV-2 was adapted to bats, but the spike gene donor was adapted to humans. Further analyses suggest that the ancestral coronavirus adapted to bats was shortly passaged in treeshrews, while the donor of the spike gene was shortly passaged in rats before the recombination event.

Population Structure of Moniliophthora perniciosa in the Main Cacao Producing Departments of Colombia.

The witches' broom (Moniliophthora perniciosa) is considered as one of the main threats for cacao production and, consequently, for chocolate production worldwide. In this work, the genetic diversity and population structure of M. perniciosa were analyzed for 59 isolates collected in five departments of Colombia and using 10 microsatellite markers. Analyses revealed 35 multilocus genotypes and clonal populations structure according to linkage disequilibrium analysis. One of the objectives of this study was to determine whether populations were differentiated by geographic origin or Theobroma cacao host genotype. Analysis of molecular variance, discriminant analysis of principal components, and Bruvo genetic distance suggested that the genetic structure was driven by geographic origin and not by T. cacao genotype. The results of this study were consistent with previous findings obtained in other cocoa-producing countries. Important insights were discussed regarding the dispersal patterns of the pathogen in Colombia and the genetic change of its populations because of different environmental conditions.

Verticillium diseases of vegetable crops in Brazil: Host range, microsclerotia production, molecular haplotype network, and pathogen species determination

AbstractRecent outbreaks of Verticillium wilt diseases in various vegetable crops have been reported in Brazil. This fact was our initial stimulus to carry out a nationwide survey aiming to determine their causal agent(s). Thus far, Verticillium dahliae has been reported as the predominant species based solely on morphological traits. As other Verticillium species can be associated with wilt diseases, we characterized a collection of 80 isolates, collected across 10 agricultural Brazilian regions, by combining morphological, biological, and molecular traits. A multilocus approach was employed for identification of Verticillium species with information from three genomic regions (ribosomal internal transcribed spacer region, glyceraldehyde‐3‐phosphate dehydrogenase, and actin genes). Only 21 out of the 80 isolates were unable to produce microsclerotia in culture. The analyses of all genomic regions indicated V. dahliae as the sole species associated with vascular wilt of distinct hosts, including major solanaceous vegetables and other hosts such as strawberry, okra, and cacao. Pathogenicity tests confirmed the infection by the V. dahliae isolates and the development of typical disease symptoms on their original hosts. This is the first nationwide characterization of Verticillium isolates associated with major vegetable crops in Neotropical areas. This provides valuable information to design sound management strategies for these diseases, mainly for establishing efficient rotation systems and for the development of resistant cultivars.

Fitness consequences of host colonization in two generalist fleas: Context-dependency and the effect of spatial co-occurrence.

We studied the fitness consequences of colonizing a novel host by experimental lines of fleas (Synosternus cleopatrae and Xenopsylla ramesis) maintained for 18-22 generations on the principal or novel (sympatric or allopatric) hosts via number, developmental success and size of the offspring of the fleas exploiting these hosts. We asked whether (a) fitness on non-principal hosts increases after prolonged maintenance; (b) the colonization success depends on the spatial co-occurrence of a flea and a host and (c) colonization of a novel host is accompanied by a decreased ability to exploit an original host. The ability of fleas to colonize novel hosts differed between species, with S. cleopatrae, but not X. ramesis, increasing its offspring production on novel hosts. Spatial co-occurrence did not affect colonization success. Maintenance on an alternative host was not accompanied by decreased adaptation to the original host. When fleas returned to the original host, their reproductive output was higher than that of their ancestors. We conclude that the success of colonizing a novel host is (a) context-dependent and varies between flea and host species and (b) not accompanied by the loss of ability to exploit an ancestral host but may lead to an increase in this ability.

A wMel Wolbachia variant in Aedes aegypti from field-collected Drosophila melanogaster with increased phenotypic stability under heat stress.

SummaryMosquito‐borne diseases remain a major cause of morbidity and mortality. Population replacement strategies involving the wMel strain of Wolbachia are being used widely to control mosquito‐borne diseases. However, these strategies may be influenced by temperature because wMel is vulnerable to heat. wMel infections in Drosophila melanogaster are genetically diverse, but few transinfections of wMel variants have been generated in Aedes aegypti. Here, we successfully transferred a wMel variant (termed wMelM) originating from a field‐collected D. melanogaster into Ae. aegypti. The new wMelM variant (clade I) is genetically distinct from the original wMel transinfection (clade III), and there are no genomic differences between wMelM in its original and transinfected host. We compared wMelM with wMel in its effects on host fitness, temperature tolerance, Wolbachia density, vector competence, cytoplasmic incompatibility and maternal transmission under heat stress in a controlled background. wMelM showed a higher heat tolerance than wMel, likely due to higher overall densities within the mosquito. Both wMel variants had minimal host fitness costs, complete cytoplasmic incompatibility and maternal transmission, and dengue virus blocking under laboratory conditions. Our results highlight phenotypic differences between Wolbachia variants and wMelM shows potential as an alternative strain in areas with strong seasonal temperature fluctuations.

Fusarium graminearum Species Complex: A Bibliographic Analysis and Web-Accessible Database for Global Mapping of Species and Trichothecene Toxin Chemotypes.

Fusarium graminearum is ranked among the five most destructive fungal pathogens that affect agroecosystems. It causes floral diseases in small grain cereals including wheat, barley, and oats, as well as maize and rice. We conducted a systematic review of peer-reviewed studies reporting species within the F. graminearum species complex (FGSC) and created two main data tables. The first contained summarized data from the articles including bibliographic, geographic, methodological (ID methods), host of origin and species, while the second data table contains information about the described strains such as publication, isolate code(s), host/substrate, year of isolation, geographical coordinates, species and trichothecene genotype. Analyses of the bibliographic data obtained from 123 publications from 2000 to 2021 by 498 unique authors and published in 40 journals are summarized. We describe the frequency of species and chemotypes for 16,274 strains for which geographical information was available, either provided as raw data or extracted from the publications, and sampled across six continents and 32 countries. The database and interactive interface are publicly available, allowing for searches, summarization, and mapping of strains according to several criteria including article, country, host, species and trichothecene genotype. The database will be updated as new articles are published and should be useful for guiding future surveys and exploring factors associated with species distribution such as climate and land use. Authors are encouraged to submit data at the strain level to the database, which is accessible at https://fgsc.netlify.app.