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The epiphytic bacteria in aquatic ecosystems, inhabiting a unique ecological niche with significant ecological function, have long been the subject of attention. Habitat characteristics and plant species are believed to be important in controlling the assembly of epiphytic bacteria. However, the underlying principle governing the assembly of the epiphytic bacterial community on macrophytes is far from clear. In this study, we systematically compared the diversity and community composition of epiphytic bacteria both in different habitats and on different species of macrophytes where they were attached. Results suggested that neither the plant species nor the habitat had a significant effect on the diversity and community of epiphytic bacteria independently, indicating that the epiphytic bacterial community composition was correlated to both geographical distance and individual species of macrophytes. Furthermore, almost all of the abundant taxa were shared between different lake regions or macrophyte species, and the most abundant bacteria belonged to Proteobacteria and Firmicutes. Our results demonstrated that the competitive lottery model may explain the pattern of epiphytic bacterial colonization of submerged macrophyte surfaces. This research could provide a new perspective for exploring plant-microbe interaction in aquatic systems and new evidence for the lottery model as the mechanism best explaining the assembly of epiphytic bacteria. [ABSTRACT FROM AUTHOR]

Generally, competition excludes pairs of phylogenetically close species across the landscape. However, habitat, food and behaviour differentiation facilitate co‐occurrence of syntopic species. The taxa of frog‐biting midges Corethrella are assumed to be specialists on calling male frogs, but little is known about how habitat gradients and frog‐species composition influence their distribution and permit their coexistence in continuous landscapes.Our aims were to understand how environmental gradients in habitat, sound frequencies and frog‐species composition influence Corethrella spp. distributions and if habitat and sound frequencies segregate their occurrence across a landscape. We also investigated if habitat selection reduces co‐occurrence of species that share similar acoustic niches. The study was conducted in 20 permanent plots in Central Amazonia using different sound attractants as baits to capture Corethrella species.Habitat gradients, sound frequencies and frog‐species composition all influenced distributions of Corethrella spp. However, these factors do little to avoid Corethrella co‐occurrence, and habitat selection did not reduce co‐occurrence of species attracted to the same sound frequencies. These results suggest that competition is unlikely to affect the distribution of adults and that other aspects, such as competition in the larval phase, may be more important to permit their coexistence.The two most abundant species showed strong negative correlations in abundances, potentially indicating competition among these species, but larval habitat specialisation is likely to be the most important cause of this pattern. [ABSTRACT FROM AUTHOR]

On a global scale, Fusarium head blight (FHB) is one of the most noxious diseases of wheat and barley. One or two Fusarium species out of 17 pathogens implicated in the complex FHB disease do not have vertical races following infection in bread wheat; however, no reports support this observation in durum wheat and barley. To end this, 16 fungal isolates of varying aggressiveness of four Fusarium species were tested on eight bread and durum wheat and barley cultivars covering a wide range from moderate resistance to susceptibility. Nine pathogenic components obtained under in vitro, growth chamber and field conditions were measured to determine whether true vertical races exist within the four tested Fusarium species. Although combined analysis of bio-experiments showed that isolate × cultivar interactions were significant, this relationship was unstable over experiments. However, the tested three bread wheat, three durum wheat and two barley cultivars showed consistent resistance to fungal isolates within each tested species, showing that F. culmorum, F. solani, F. verticillioides, and F. equiseti do not have vertical races. Our data concluded that the resistance to FHB in wheat and barley was of the horizontal and non-species specific type. There was no signal for any vertical genes in all tested Fusarium species. Consequently, the resistance genes in sources presently employed in breeding programs are not expected to succumb to new FHB races in the near future. To our best knowledge, this is the first report to show the absence of vertical Fusarium races upon infection durum wheat and barley, and is harmony with earlier reports conduced with bread wheat infected with F. graminearum and F. culmorum. [ABSTRACT FROM AUTHOR]

Tamarisk is an invasive evergreen shrub native to arid regions of Africa and Eurasia and is considered a weed in some countries with dry climates. The complex of gall mites from tamarisks includes fourteen species from four genera of the family Eriophyidae. We reinvestigated the type species of the genus Dicruvasates, D. tamaricis from Egypt, described D. ngubani n. sp. from Tamarix usneoides from South Africa, and revised the generic concept of Dicruvasates. This genus possesses cuticular plates marking longitudinal opisthosomal ridges typical of various phyllocoptine genera, e.g., Echinacrus. We sequenced three genes of Dicruvasates and Phyllocoptes mites from Tamarix and Echinacrus from Frangula, combined our sequences with the data from GenBank, and performed single-gene phylogenetic analyses. All analyses inferred the following: (1) a transcontinental clade Tam comprising Dicruvasates + Aceria + Phyllocoptes from Tamarix; (2) Echinacrus distantly related to Dicruvasates, suggesting the homoplastic nature of the cuticular plates on the opisthosomal ridges, and (3) polyphyly of the genera Aceria and Phyllocoptes. We also investigated partially cleared specimens of Dicruvasates under CLSM and, for the first time, visualized a well-developed anal secretory apparatus (ASA) in the immatures of gall mites, which was previously shown to be a specialized system evolved in Eriophyoidea for silk production. We hypothesize that the ASA contributes to finding nymphs by conspecific males and advocate for the importance of the future molecular biology studies of gall mite silk for developing new methods for controlling mites based on the knowledge of their ecology, behavior, and silk gene genetics. [ABSTRACT FROM AUTHOR]

Intraspecific autoparasitism, the phenomenon in which a parasite serves as the host for another individual of the same species, is a well-described interaction among hemiparasitic flowering plants. Here, I describe a rare case of autoparasitism in Epifagus virginiana (L.) W.P.C. Barton (Orobanchaceae), a holoparasitic plant normally found exclusively on the roots of Fagus grandifolia Ehrh. (Fagaceae). Confirmation of the autoparasitic relationship was obtained through microtomography and anatomical analyses. Results show the presence of vessel connections between the two E. virginiana plants and the unobstructed passage of solutes from one plant to another, thus suggesting the autoparasitic connection to be fully functional. While several segments of nearby host roots were entangled with the adventitious roots of the parasite, no parasite–host vascular connection was detected. Additionally, an analysis of digitized herbarium specimens showed that albeit rare, the observed autoparasitic relationship in E. virginiana is not a one-of case. A total of 3097 digitized herbarium specimens were also analyzed, among which 1.69% were observed to potentially include an autoparasitic connection. Altogether, these results provide new clues for the investigation of host-specificity and haustorium development processes in parasitic flowering plants. [ABSTRACT FROM AUTHOR]

Simple Summary: The gray wolf (Canis lupus) is the largest representative of the family Canidae widespread in Eurasia and North America. Sarcocystis and Trichinella parasites were previously reported in the muscles of gray wolves. Apicomplexan Sarcocystis forms sarcocysts in the muscles of intermediate hosts and develops sporocysts in the intestines of definite hosts. Members of the genus Trichinella are cosmopolitan hazardous nematodes. The species composition of these parasites in gray wolves from Lithuania has not been studied so far. We examined muscle samples from 15 gray wolves, and species of parasites were confirmed using DNA analysis methods. Microscopically, Trichinella larvae were observed in 12 animals, and sarcocysts formed by Sarcocystis spp. were noticed in four. Trichinella britovi was also identified in the examined wolves. Current data show that zoonotic T. britovi is the dominant Trichinella species in gray wolves from nearby countries. In the case of Sarcocystis, two animals harbored S. svanai, and another two individuals were infected by S. svanai and S. arctica. Future studies are needed to assess the pathogenesis of the identified Sarcocystis spp. Apicomplexan Sarcocystis and Trichinella nematodes are food-borne parasites whose life cycle is carried-out in various wildlife and domestic animals. The gray wolf (Canis lupus) is an apex predator acting as an ecosystem engineer. This study aimed to identify the species of Sarcocystis and Trichinella found in the muscles of gray wolves in Lithuania. During the 2017–2022 period, diaphragm, heart, and hind leg samples of 15 animals were examined. Microscopical analysis showed the presence of two types of Sarcocystis parasites in 26.7% of the analyzed muscle samples. Based on the sequencing of five loci, nuclear 18S rDNA, 28S rDNA, ITS1, mitochondrial cox1, and apicoplast rpoB, S. arctica, and S. svanai were identified. The current work presents the first report of S. svanai in gray wolf. Phylogenetically, S. svanai clustered together with S. lutrae, infecting various carnivorans, and S. arctica was most closely related to S. felis from domestic cats. Trichinella spp. were found in 12 gray wolves (80%). For the first time, Trichinella species were molecularly identified in gray wolves from Lithuania. Trichinella britovi was confirmed in all of the isolated Trichinella larvae using a multiplex PCR. Gray wolves in Lithuania may serve as a major source of zoonotic pathogens due to the presence of these parasites. [ABSTRACT FROM AUTHOR]

ABSTRACT Parasites infecting migratory birds all over the world are still under investigation. The identification of parasitic taxa infecting ardeids was done concerning their morphological and morphometric features. A total of 20 Bubulcus ibis (Ardeidae) specimens were collected and investigated for nematode parasites. Only one nematode species, belonging to the Heterakidae family, has been identified, with a prevalence rate of 40% (8/20) among infected egrets. The Heterakis species isolated from the lumen of the ceca of the egret host is morphologically and morphometric compatible with Heterakis gallinarum. Additionally, utilizing the partial small subunit ribosomal RNA (18S rRNA) and mitochondrial cytochrome c oxidase subunit I (COI) genes, maximum parsimony based on the Tamura-Nei model was used to infer the phylogeny of the recovered Heterakis species. The query sequences revealed 99.61% and 97.11% identities for the 18S (MK844591.1) and COI (MF066715.1) genes of the previously mentioned H. gallinarum. In addition to clarifying several morphological features of H. gallinarum, this study also provided new DNA data for this species. The combination of morphological and molecular data could be helpful to other veterinaries in finding a way to treat and control this infection in the cattle egret.

[Display omitted] • Mitochondrial and morphometric data were used to delimit Transversotrema species. • Almost all species of Transversotrema are shown to be morphologically cryptic. • Molecular data proved the only reliable basis for Transversotrema identification. • Ten new species are described for fishes of the tropical Indo-west Pacific. • Transversotrema is the richest trematode genus infecting Australian marine fishes. Species of Transversotrema Witenberg, 1944 (Transversotrematidae) occupy a unique ecological niche for the Trematoda, living externally under the scales of their teleost hosts. Previous studies of the genus have been impeded partly by limited variation in ribosomal DNA sequence data between closely related species and partly by a lack of morphometrically informative characters. Here, we assess richness of the tropical Indo-west Pacific species through parallel phylogenetic and morphometric analyses, generating cytochrome c oxidase subunit 1 mitochondrial sequence data and morphometric data for hologenophore specimens from Australia, French Polynesia, Japan and Palau. These analyses demonstrate that molecular data provide the only reliable basis for species identification; host distribution, and to a lesser extent morphology, are useful for identifying just a few species of Transversotrema. We infer that a combination of morphological simplicity and infection site constraint has led to the group displaying exceptionally low morphological diversification. Phylogenetic analyses of the mitochondrial data broadly support previous systematic interpretations based on ribosomal data, but also demonstrate the presence of several morphologically and ecologically cryptic species. Ten new species are described, eight from the Great Barrier Reef, Australia (Transversotrema chrysallis n. sp., Transversotrema daphnidis n. sp., Transversotrema enceladi n. sp., Transversotrema hyperionis n. sp., Transversotrema iapeti n. sp., Transversotrema rheae n. sp., Transversotrema tethyos n. sp., and Transversotrema titanis n. sp.) and two from off Japan (Transversotrema methones n. sp. and Transversotrema panos n. sp.). There are now 26 Transversotrema species known from Australian marine fishes, making it the richest trematode genus for the fauna. [ABSTRACT FROM AUTHOR]

Truffles in the genus Tuber host and feed a wide community of organisms including insects, bacteria, and fungi. Among microorganisms, truffle-inhabiting fungi (TIF) have been poorly investigated and only a limited number of yeast and filamentous species have been identified. In this work we isolated and barcoded culturable TIF from 16 ascomata of T. melanosporum, T. aestivum and T. borchii of different provenances. Eighteen strains were identified a species level, four at genus level and one at order level. Penicillium was the most represented genus with five species and the only TIF genus isolated from T. melanosporum ascomata. Six TIF had colonies with a yeast morphology, including two species of Candida. Five species (Leohumicola sp., Knufia tsunedae, Hypocreales sp., Sagenomella cf. verticillata, Kondoa sp.) had rare ITS sequences compared to those deposited in GenBank. Except Peniophora cinerea, all TIF identified in this work have never been reported in Tuber ascomata until now. In-depth investigations on TIF and their host specificity are needed to evaluate the effects of these fungi on the truffle life cycle and the quality of ascomata. [ABSTRACT FROM AUTHOR]

Arthonia epipolytropa Hafellner & Grube and Arthonia subclemens Hafellner, Grube & Muggia are described as new to science. Both are specific parasites of Lecanora polytropa s. lat., but of differing pathogenicity and of very different appearance. Whereas the clearly parasitic Arthonia epipolytropa with its agglomerated ascomata is presently known with certainty from a number of localities along the arch of the Alps (Austria, Italy, Switzerland), other parts of Europe (Norway, Albania) and northern America (USA), the less harmful A. subclemens with its isolated sunken ascomata is currently known only from a small number of localities in the Eastern Alps (Austria, Italy) and various mountain ranges in southern Europe (Spain, North Macedonia, Greece). The species are compared with other Arthonia species known from Lecanora or one of its recently segregated genera. A key to the fungi regularly found on Lecanora polytropa s. lat. is presented. [ABSTRACT FROM AUTHOR]

The leaf beetle Leptinotarsa texana is a potential biological control agent for silverleaf nightshade Solanum elaeagnifolium in Australia. However, previous research has shown that L. texana can develop on the non-target crop eggplant Solanum melongena in quarantine cage experiments. We used open-field experiments in the agent's native range of Texas, USA, to clarify the realised host-range of L. texana in relation to S. melongena. We conducted five replicated field experiments to investigate: (1) the extent that L. texana would show a preference for oviposition when presented with both S. elaeagnifolium and S. melongena in an open-field context, and (2) the extent that larvae would move from defoliated S. elaeagnifolium onto either nearby S. melongena plants, or bypass S. melongena in search of S. elaeagnifolium. We found, in the open-field experiments, that adult females prefer S. elaeagnifolium over S. melongena plants for settling and oviposition and, in fact, observed no oviposition on S. melongena in any experiment. However, the low levels of oviposition observed in the S. elaeagnifolium experimental plants (the control) was insufficient to conclusively demonstrate that S. melongena is not within the realised host-range of L. texana adults. We also found evidence that L. texana larvae can cause spill-over damage to S. melongena in situations where co-occurring S. elaeagnifolium is defoliated. Finally, we demonstrate the use of an argument map to visually represent the contributions of multiple, sometimes conflicting, field and laboratory experiments to biological control agent risk analysis. [ABSTRACT FROM AUTHOR]

Abstract Background Escherichia coli is an opportunistic pathogen which colonizes various host species. However, to what extent genetic lineages of E. coli are adapted or restricted to specific hosts and the genomic determinants of such adaptation or restriction is poorly understood. Results We randomly sampled E. coli isolates from four countries (Germany, UK, Spain, and Vietnam), obtained from five host species (human, pig, cattle, chicken, and wild boar) over 16 years, from both healthy and diseased hosts, to construct a collection of 1198 whole-genome sequenced E. coli isolates. We identified associations between specific E. coli lineages and the host from which they were isolated. A genome-wide association study (GWAS) identified several E. coli genes that were associated with human, cattle, or chicken hosts, whereas no genes associated with the pig host could be found. In silico characterization of nine contiguous genes (collectively designated as nan-9) associated with the human host indicated that these genes are involved in the metabolism of sialic acids (Sia). In contrast, the previously described sialic acid regulon known as sialoregulon (i.e. nanRATEK-yhcH, nanXY, and nanCMS) was not associated with any host species. In vitro growth experiments with a Δnan-9 E. coli mutant strain, using the sialic acids 5-N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) as sole carbon source, showed impaired growth behaviour compared to the wild-type. Conclusions This study provides an extensive analysis of genetic determinants which may contribute to host specificity in E. coli. Our findings should inform risk analysis and epidemiological monitoring of (antimicrobial resistant) E. coli.

Abstract Copepods provide a rich organic microenvironment allowing the settlement and proliferation of microorganisms, forming dynamic microbial hotspots in the oceans. Such symbiotic associations in the plankton were previously hypothesized to be especially developed in warm oligotrophic seas, as they may serve as alternative sources of nutrients in biologically poor waters. Aiming to better understand how copepod microbiomes are shaped in an oligotrophic sea, we characterized microbiota associated with three dominant coastal epipelagic copepod species in the ultra‐oligotrophic Eastern Mediterranean Sea using amplicon sequencing of the 16S rRNA gene. Our results show that copepod‐associated microbial communities were host‐specific rather than determined by seasonal environmental changes. In the filter‐feeding copepod with a tendency to herbivory, Temora stylifera, microbial diversity was low and relatively stable throughout the year. In contrast, omnivorous copepods, the ambush‐feeding Oithona nana, and the mixed‐feeding Centropages ponticus harbored more diverse microbiomes dominated by transient taxa. We suggest that filter‐feeding strategy and narrow food spectrum can limit copepod–microbe interactions, while the ambush and mixed feeding strategies combined with omnivory confer higher microbial diversity. Filter feeders may reduce the recruitment of opportunistic microbes by maintaining high fidelity associations, as indicated by the large number of core taxa in T. stylifera. We underline the importance of the copepod–microbe associations in nutrient‐impoverished ecosystems, based on predicted enrichment of nitrogen metabolism in the core microbiome, mostly during summer when the shallow coastal waters are nitrogen‐depleted.

The genetically related assemblages of the intestinal protozoa parasite Giardia lamblia are morphologically indistinguishable and are often derived from specific hosts. The Giardia assemblages are separated by large genetic distances, which might account for their relevant biological and pathogenic differences. In this work, we analyzed the RNAs cargo released into exosomal-like vesicles (ElVs) by the assemblages A and B, which differentially infect humans, and the assemblage E, which infects hoofed animals. The RNA sequencing analysis revealed that the ElVs of each assemblage contained distinct small RNA (sRNA) biotypes, suggesting a preference for specific packaging in each assemblage. These sRNAs were classified into three categories, ribosomal-small RNAs (rsRNAs), messenger-small RNAs (msRNAs), and transfer-small RNAs (tsRNAs), which may play a regulatory role in parasite communication and contribute to host-specificity and pathogenesis. Uptake experiments showed, for the first time, that ElVs were successfully internalized by the parasite trophozoites. Furthermore, we observed that the sRNAs contained inside these ElVs were first located below the plasma membrane but then distributed along the cytoplasm. Overall, the study provides new insights into the molecular mechanisms underlying the host-specificity and pathogenesis of G. lamblia and highlights the potential role of sRNAs in parasite communication and regulation. [ABSTRACT FROM AUTHOR]

Coral reefs accommodate a myriad of species, many of which live in association with a host organism. Decapod crustaceans make up a large part of this associated fauna on coral reefs. Among these, cryptochirid crabs are obligately associated with scleractinian corals, in which they create dwellings where they permanently reside. These gall crabs show various levels of host specificity, with the majority of cryptochirids inhabiting a specific coral genus or species. Here, we report the first records of gall crabs living in association with two different Porites species in the Red Sea. Crescent‐shaped dwellings were observed in Porites rus and a Porites sp. in situ, and colonies with crabs were collected for further study in the laboratory. Using a combination of morphology and DNA barcoding, the crabs were identified as belonging to Opecarcinus, a genus only known to inhabit Agariciidae corals. The coral skeleton was bleached and studied under a stereo microscope, which revealed that the Porites corals overgrew adjoining agariciid Pavona colonies. We hypothesize that the gall crab originally settled on Pavona, its primary host of choice. Due to coral interspecific competition the Porites colony overgrew the adjacent Pavona colonies, resulting in a secondary and never before reported association of Opecarcinus with Porites. These findings suggest that cryptochirid crabs can adapt to the new microenvironment provided by a different coral host and survive competition for space on coral reefs. [ABSTRACT FROM AUTHOR]

Rhytisma Fr. is the type genus of Rhytismataceae (Rhytismatales, Leotiomycetes, Ascomycota). Rhytisma-like species include members of Cryptomyces, Rhytisma and Vladracula. They are parasites on leaves of broadleaf trees and cause tar spot diseases. In this study, a phylogeny based on the large subunit of the ribosomal rRNA gene (nrLSU) and the mitochondrial small subunit (mtSSU) is presented, including sequences of 39 newly collected specimens from East Asia, Europe, and temperate as well as tropical America. Based on analyses of morphology, phylogeny as well as host-specificity and diversification time estimates, the family Rhytismataceae sensu stricto is proposed, and eight genera are accepted in this narrow family, including four novel genera (Densorhytisma, Fanglania, Johnstoniella and Shiqia), the type genus Rhytisma, and the reinstated genera Lophodermina, Placuntium and Xyloma. Lophodermina clusters within the main Rhytisma clade in our analyses, but is divergent in morphological terms, not having large compound stromata. Thirty species are recognized, including seven novel species (Fanglania hubeiensis, F. parasitica, Johnstoniella yunnanensis, Rhytisma japonicum, Rh. taiwanense, Xyloma globosum, and X. shennongjiaense), fifteen new combinations (Densorhytisma anhuiense, D. huangshanense, F. concova, F. himalensis, F. ilicis-integrae, F. ilicis-latifoliae, F. ilicis-pedunculosae, J. lonicerae, Rh. annuliforme, Shiqia menziesii, S. yuexiensis, X. filamentosum, X. maximum, X. muelleri, and X. polare), one new name (J. xylostei), seven known species (Lophodermina melaleuca, Placuntium andromedae, Rhytisma acerinum, Rh. americanum, Rh. punctatum, X. salicinum, and X. umbonatum). In addition, seven immature specimens were studied but not assigned to existing species, herein referred to as Fanglania sp. 1, Johnstoniella sp. 1, Johnstoniella sp. 2, Placuntium sp. 1, Placuntium sp. 2, Rhytisma sp. 1, and Xyloma sp. 1. The systematic positions of Cryptomyces maximus, Cr. muelleri and Vladracula annuliformis are re-assigned based on phylogenetic analysis. One Rhytisma-like species from tropical America was segregated from Rhytismataceae s.str., thus a novel genus Neorhytisma was established to accommodate this species, with the one new combinations Neorhytisma panamense. The results of the molecular phylogenetic analysis indicate that Rhytisma-like species are host-specific at genus level. Apparently, Rhytisma-like species coevolved with their hosts, and Rhytisma-like species on Ericaceae seem to be in the process of host jumping. Morphological characteristics of ascomata are important for the delimitation of species and genera of Rhytisma-like species. This study provides a key to genera and species of recognized Rhytisma-like species worldwide. [ABSTRACT FROM AUTHOR]

Apicomplexan Sarcocystis and Trichinella nematodes are food-borne parasites whose life cycle is carried-out in various wildlife and domestic animals. The gray wolf (Canis lupus) is an apex predator acting as an ecosystem engineer. This study aimed to identify the species of Sarcocystis and Trichinella found in the muscles of gray wolves in Lithuania. During the 2017–2022 period, diaphragm, heart, and hind leg samples of 15 animals were examined. Microscopical analysis showed the presence of two types of Sarcocystis parasites in 26.7% of the analyzed muscle samples. Based on the sequencing of five loci, nuclear 18S rDNA, 28S rDNA, ITS1, mitochondrial cox1, and apicoplast rpoB, S. arctica, and S. svanai were identified. The current work presents the first report of S. svanai in gray wolf. Phylogenetically, S. svanai clustered together with S. lutrae, infecting various carnivorans, and S. arctica was most closely related to S. felis from domestic cats. Trichinella spp. were found in 12 gray wolves (80%). For the first time, Trichinella species were molecularly identified in gray wolves from Lithuania. Trichinella britovi was confirmed in all of the isolated Trichinella larvae using a multiplex PCR. Gray wolves in Lithuania may serve as a major source of zoonotic pathogens due to the presence of these parasites.

Background: Escherichia coli is an opportunistic pathogen which colonizes various host species. However, to what extent genetic lineages of E. coli are adapted or restricted to specific hosts and the genomic determinants of such adaptation or restriction is poorly understood. Results: We randomly sampled E. coli isolates from four countries (Germany, UK, Spain, and Vietnam), obtained from five host species (human, pig, cattle, chicken, and wild boar) over 16 years, from both healthy and diseased hosts, to construct a collection of 1198 whole-genome sequenced E. coli isolates. We identified associations between specific E. coli lineages and the host from which they were isolated. A genome-wide association study (GWAS) identified several E. coli genes that were associated with human, cattle, or chicken hosts, whereas no genes associated with the pig host could be found. In silico characterization of nine contiguous genes (collectively designated as nan-9) associated with the human host indicated that these genes are involved in the metabolism of sialic acids (Sia). In contrast, the previously described sialic acid regulon known as sialoregulon (i.e. nanRATEK-yhcH, nanXY, and nanCMS) was not associated with any host species. In vitro growth experiments with a Δnan-9 E. coli mutant strain, using the sialic acids 5-N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) as sole carbon source, showed impaired growth behaviour compared to the wild-type. Conclusions: This study provides an extensive analysis of genetic determinants which may contribute to host specificity in E. coli. Our findings should inform risk analysis and epidemiological monitoring of (antimicrobial resistant) E. coli. [ABSTRACT FROM AUTHOR]

Background: Gymnosporangium asiaticum and G. yamadae can share Juniperus chinensis as the telial host, but the symptoms are completely different. The infection of G. yamadae causes the enlargement of the phloem and cortex of young branches as a gall, but not for G. asiaticum, suggesting that different molecular interaction mechanisms exist the two Gymnosporangium species with junipers. Results: Comparative transcriptome analysis was performed to investigate genes regulation of juniper in responses to the infections of G. asiaticum and G. yamadae at different stages. Functional enrichment analysis showed that genes related to transport, catabolism and transcription pathways were up-regulated, while genes related to energy metabolism and photosynthesis were down-regulated in juniper branch tissues after infection with G. asiaticum and G. yamadae. The transcript profiling of G. yamadae-induced gall tissues revealed that more genes involved in photosynthesis, sugar metabolism, plant hormones and defense-related pathways were up-regulated in the vigorous development stage of gall compared to the initial stage, and were eventually repressed overall. Furthermore, the concentration of cytokinins (CKs) in the galls tissue and the telia of G. yamadae was significantly higher than in healthy branch tissues of juniper. As well, tRNA-isopentenyltransferase (tRNA-IPT) was identified in G. yamadae with highly expression levels during the gall development stages. Conclusions: In general, our study provided new insights into the host-specific mechanisms by which G. asiaticum and G. yamadae differentially utilize CKs and specific adaptations on juniper during their co-evolution. [ABSTRACT FROM AUTHOR]

Abstract Background Bacterial identification at the strain level is a much-needed, but arduous and challenging task. This study aimed to develop a method for identifying and differentiating individual strains among multiple strains of the same bacterial species. The set used for testing the method consisted of 17 Escherichia coli strains picked from a collection of strains isolated in Germany, Spain, the United Kingdom and Vietnam from humans, cattle, swine, wild boars, and chickens. We targeted unique or rare ORFan genes to address the problem of selective and specific strain identification. These ORFan genes, exclusive to each strain, served as templates for developing strain-specific primers. Results Most of the experimental strains (14 out of 17) possessed unique ORFan genes that were used to develop strain-specific primers. The remaining three strains were identified by combining a PCR for a rare gene with a selection step for isolating the experimental strains. Multiplex PCR allowed the successful identification of the strains both in vitro in spiked faecal material in addition to in vivo after experimental infections of pigs and recovery of bacteria from faecal material. In addition, primers for qPCR were also developed and quantitative readout from faecal samples after experimental infection was also possible. Conclusions The method described in this manuscript using strain-specific unique genes to identify single strains in a mixture of strains proved itself efficient and reliable in detecting and following individual strains both in vitro and in vivo, representing a fast and inexpensive alternative to more costly methods.

A cluster of genes involved in pea pathogenicity reside on the conditionally dispensable PDA1 -chromosome of Fusarium vanettenii (Fv), a pathogen on garden pea. Among these genes, cDNA3 is interesting due to its presence only in highly virulent field isolates and its unknown function. A mutant of cDNA3 was generated and its virulence on pea was significantly reduced when compared to the wild type isolate. The expression of the other PEP genes was altered in the cDNA3 mutant after treatment with pisatin. Despite the difference in expression of the PEP genes, the cDNA3 mutant did not display increased sensitivity to pisatin. Of the Fv genomes that encode cDNA3, the amino acid sequence was highly conserved including at five potential phosphorylation sites. As a biological function of cDNA3 has been elucidated in Fv , we propose to rename cDNA3 to p isatin- r esponsive g ene, PRG1. • CDNA3 is a virulence factor of Fusarium vanettenii for garden pea. • CDNA3 is expressed after treatment with the phytoalexin pisatin and during infection of pea. • Expression of the four other genes in the pea pathogenicity (PEP) cluster is upregulated after treatment with pisatin in the presence of cDNA3. • As a function has now been identified for cDNA3 , we propose to rename it PRG1 for pisatin responsive gene. [ABSTRACT FROM AUTHOR]

Abstract Blast diseases of rice and wheat are known to be caused by the specific pathotypes of Magnaporthe oryzae (syn. Pyricularia oryzae), M. oryzae Oryzae (MoO) and M. oryzae Triticum (MoT), respectively. Rice blast disease has been seen in Bangladesh from a very ancient time. However, Bangladesh’s first epidemic outbreak of wheat blast was recorded in 2016. This study aimed to investigate the cross-infection reactions of MoO and MoT in rice and wheat in a growth room condition. Artificial inoculation was done at vegetative and reproductive phases of both wheat and rice plants in a completely randomized design using virulent isolates of MoO and MoT. Artificial inoculation with MoO resulted in foliar symptoms with typical eye-shaped lesions as well as partially bleached or completely white head symptoms in both wheat and rice plants. On the other hand, MoT produced blast symptoms only on the leaves and spikes of wheat. Molecular analyses using PCR amplification (with Pot2, MoT3 and MoT6099 primers) and a recently developed rapid detection PCRD strip confirmed the presence of MoT and MoO pathotypes in the symptomatic plant samples. Our results demonstrated that MoO pathotype can infect the leaves and spikes of wheat but MoT is unable to infect rice plants under the same controlled environment in Bangladesh. This study has revealed the vulnerability of wheat to MoO pathotype and an urgent need to understand the molecular mechanism underlying host-specificity of the blast fungus M. oryzae. Our results also provided evidence for a potential wheat blast epidemic by MoO in many rice–wheat inter-cropping regions as climate change intensifies. A comprehensive study is needed to have a better understanding on the variability in virulence of MoO and MoT isolates in infecting wheat and rice under controlled environment by the inclusion of a large number of isolates and crop varieties/genotypes.

Ascidians or sea squirts are among the marine taxa with the most introduced species worldwide. These animals have a suite of biological characteristics that contribute to their successful establishment, including long reproductive seasons, rapid growth rates, and resistance to pollution. Here, we sequenced a fragment of the 16S ribosomal RNA gene to characterize symbiont diversity and host-specificity in the solitary species Syela clava and Ascidiella aspersa, and the colonial species Didemnum vexillum. Samples were collected from introduced populations in several marinas and mussel facilities around Ireland, and a marina in New Zealand. Two additional colonial species Botrylloides violaceus and Didemnum sp. were collected in Ireland, and ambient seawater was sampled from both countries for comparison. Data revealed a strong effect of host species and location on prokaryote symbiont composition, consistent with recent ascidian microbiome literature. However, a location effect did not manifest in alpha diversity metrics (e.g., the same ascidian species at different locations exhibited similar diversity) but was evident in beta diversity metrics (greater intra-specific differences across locations than within locations). Location effects were stronger than species effects only for the solitary species (i.e., A. aspersa from New Zealand was more similar to S. clava from New Zealand than to A. aspersa from Ireland). D. vexillum and A. aspersa hosted a high abundance of prokaryotic symbionts that were previously found in other ascidian species, while S. clava symbiotic community was more closely related to bacteria common in the marine environment. Further studies should aim to unravel host-microbe coevolutionary patterns and the microbial role in facilitating host establishment in different habitats. [ABSTRACT FROM AUTHOR]

Mosquitoes are vectors of various pathogens that cause diseases in humans and animals. To prevent the outbreak of mosquito-borne diseases, it is essential to control vector populations, as treatment or vaccination for mosquito-borne diseases are often unavailable. Insect-specific viruses (ISVs) have previously been described as being potentially helpful against arboviral disease outbreaks. In this study, we present the first in vivo characterization of the ISV Culex Y virus (CYV). CYV was first isolated from free-living Culex pipiens mosquitoes in 2010; then, it was found in several mosquito cell lines in a further study in 2018. For mammalian cells, we were able to confirm that CYV does not replicate as it was previously described. Additionally, we found that CYV does not replicate in honey bees or locusts. However, we detected replication in the Culex pipiens biotype molestus, Aedes albopictus, and Drosophila melanogaster, thus indicating dipteran specificity. We detected significantly higher mortality in Culex pipiens biotype molestus males and Drosophila melanogaster, but not in Aedes albopictus and female Culex pipiens biotype molestus. CYV could not be transmitted transovarially to offspring, but we detected venereal transmission as well as CYV in mosquitos' saliva, indicating that an oral route of infection would also be possible. CYV's dipteran specificity, transmission routes, and killing effect with respect to Culex males may be used as powerful tools with which to destabilize arbovirus vector populations in the future. [ABSTRACT FROM AUTHOR]

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Strains of Erwinia tracheiphila, causal agent of bacterial wilt of cucurbits, are divided into distinct clades. Et-melo clade strains wilt Cucumis spp. but not Cucurbita spp., thus exhibiting host specificity, whereas Et-C1 clade strains wilt Cucurbita spp. more rapidly than Cucumis melo, thus exhibiting a host preference. This study investigated the contribution of the effector proteins Eop1 and DspE to E. tracheiphila pathogenicity and host adaptation. Loss of eop1 did not enable Et-melo strains to infect squash (Cucurbita pepo) or an Et-C1 strain to induce a more rapid wilt of muskmelon (Cucumis melo), indicating that Eop1 did not function in host specificity or preference as in the related pathogen E. amylovora. However, overexpression of eop1 from Et-melo strain MDCuke but not from Et-C1 strain BHKY increased the virulence of a BHKY eop1 deletion mutant on muskmelon, demonstrating that the Eop1 variants in the two clades are distinct in their virulence functions. Loss of dspE from Et-melo strains reduced but did not eliminate virulence on hosts muskmelon and cucumber, whereas loss of dspE from an Et-C1 strain eliminated pathogenicity on hosts squash, muskmelon, and cucumber. Thus, the centrality of DspE to virulence differs in the two clades. Et-melo mutants lacking the chaperone DspF exhibited similar virulence to mutants lacking DspE, indicating that DspF is the sole chaperone for DspE in E. tracheiphila, unlike in E. amylovora. Collectively, these results provide the first functional evaluation of effectors in E. tracheiphila and demonstrate clade-specific differences in the roles of Eop1 and DspE.[Graphic: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Investigations on the parasites that infect migrating birds worldwide are ongoing. To identify the parasite species that infect ardeids, morphological and morphometric characteristics were used. A total of 20 Bubulcus ibis (Ardeidae) specimens were collected from the agricultural lands belonging to the Faculty of Agricultural at Cairo University, which were then examined for nematode parasites. Only one acuariid species, belonging to the Acuariidae family, has been identified, with a prevalence rate of 50 % (10/20) among infected egrets. The Desportesius species isolated from the gizzard of the egret host is morphologically and morphometrically compatible with Desportesius invaginatus, which was previously identified from several Ciconiiformes hosts of Bubulcus ibis (Egypt, India, and Taiwan), Egretta garzetta (France), and Egretta rufescens (USA). Additionally, utilizing the partial small subunit ribosomal RNA (18S rRNA) gene sequence, maximum parsimony based on the Tamura-Nei model was used to infer the phylogeny of the recovered Desportesius species. The query sequences revealed 99.37 % identity for the 18S (MW358651.1) of the previously mentioned D. invaginatus. In addition to clarifying several morphological features of D. invaginatus, this study also provided new DNA data for this species.

Insect herbivores have evolved a broad spectrum of adaptations in response to the diversity of chemical defences employed by plants. Here we focus on two species of New Guinean Asota and determine how these specialist moths deal with the leaf alkaloids of their fig (Ficus) hosts. As each focal Asota species is restricted to one of three chemically distinct species of Ficus, we also test whether these specialized interactions lead to similar alkaloid profiles in both Asota species. We reared Asota caterpillars on their respective Ficus hosts in natural conditions and analyzed the alkaloid profiles of leaf, frass, caterpillar, and adult moth samples using UHPLC–MS/MS analyses. We identified 43 alkaloids in our samples. Leaf alkaloids showed various fates. Some were excreted in frass or found in caterpillars and adult moths. We also found two apparently novel indole alkaloids—likely synthesized de novo by the moths or their microbiota—in both caterpillar and adult tissue but not in leaves or frass. Overall, alkaloids unique or largely restricted to insect tissue were shared across moth species despite feeding on different hosts. This indicates that a limited number of plant compounds have a direct ecological function that is conserved among the studied species. Our results provide evidence for the importance of phytochemistry and metabolic strategies in the formation of plant–insect interactions and food webs in general. Furthermore, we provide a new potential example of insects acquiring chemicals for their benefit in an ecologically relevant insect genus. [ABSTRACT FROM AUTHOR]

The Fusarium fujikuroi species complex (FFSC) includes socioeconomically important pathogens that cause disease for numerous crops and synthesize a variety of secondary metabolites that can contaminate feedstocks and food. Here, we used comparative genomics to elucidate processes underlying the ability of pine-associated and grass-associated FFSC species to colonize tissues of their respective plant hosts. We characterized the identity, possible functions, evolutionary origins, and chromosomal positions of the host-range-associated genes encoded by the two groups of fungi. The 72 and 47 genes identified as unique to the respective genome groups were potentially involved in diverse processes, ranging from transcription, regulation, and substrate transport through to virulence/pathogenicity. Most genes arose early during the evolution of Fusarium/FFSC and were only subsequently retained in some lineages, while some had origins outside Fusarium. Although differences in the densities of these genes were especially noticeable on the conditionally dispensable chromosome of F. temperatum (representing the grass-associates) and F. circinatum (representing the pine-associates), the host-range-associated genes tended to be located towards the subtelomeric regions of chromosomes. Taken together, these results demonstrate that multiple mechanisms drive the emergence of genes in the grass- and pine-associated FFSC taxa examined. It also highlighted the diversity of the molecular processes potentially underlying niche-specificity in these and other Fusarium species. [ABSTRACT FROM AUTHOR]

Abstract Background In parasitism arm race processes and red queen dynamics between host and parasites reciprocally mold many aspects of their genetics and evolution. We performed a parallel assessment of population genetics and demography of two species of pinworms with different degrees of host specificity (Trypanoxyuris multilabiatus, species-specific; and T. minutus, genus-specific) and their host, the mantled howler monkey (Alouatta palliata), based on mitochondrial DNA sequences and microsatellite loci (these only for the host). Given that pinworms and primates have a close co-evolutionary history, covariation in several genetic aspects of their populations is expected. Results Mitochondrial DNA revealed two genetic clusters (West and East) in both pinworm species and howler monkeys, although population structure and genetic differentiation were stronger in the host, while genetic diversity was higher in pinworms than howler populations. Co-divergence tests showed no congruence between host and parasite phylogenies; nonetheless, a significant correlation was found between both pinworms and A. palliata genetic pairwise distances suggesting that the parasites’ gene flow is mediated by the host dispersal. Moreover, the parasite most infective and the host most susceptible haplotypes were also the most frequent, whereas the less divergent haplotypes tended to be either more infective (for pinworms) or more susceptible (for howlers). Finally, a positive correlation was found between pairwise p-distance of host haplotypes and that of their associated pinworm haplotypes. Conclusion The genetic configuration of pinworm populations appears to be molded by their own demography and life history traits in conjunction with the biology and evolutionary history of their hosts, including host genetic variation, social interactions, dispersal and biogeography. Similarity in patterns of genetic structure, differentiation and diversity is higher between howler monkeys and T. multilabiatus in comparison with T. minutus, highlighting the role of host-specificity in coevolving processes. Trypanoxyuris minutus exhibits genetic specificity towards the most frequent host haplotype as well as geographic specificity. Results suggest signals of potential local adaptation in pinworms and further support the notion of correlated evolution between pinworms and their primate hosts.

Abstract The relationship between entomopathogenic fungi and their insect hosts is a classic example of the co-evolutionary arms race between pathogen and target host. The present review describes the entomopathogenic potential of Chytridiomycota and Blastocladiomycota fungi, and two groups of fungal allies: Oomycota and Microsporidia. The Oomycota (water moulds) are considered as a model biological control agent of mosquito larvae. Due to their shared ecological and morphological similarities, they had long been considered a part of the fungal kingdom; however, phylogenetic studies have since placed this group within the Straminipila. The Microsporidia are parasites of economically-important insects, including grasshoppers, lady beetles, bumblebees, colorado potato beetles and honeybees. They have been found to display some fungal characteristics, and phylogenetic studies suggest that they are related to fungi, either as a basal branch or sister group. The Blastocladiomycota and Chytridiomycota, named the lower fungi, historically were described together; however, molecular phylogenetic and ultrastructural research has classified them in their own phylum. They are considered parasites of ants, and of the larval stages of black flies, mosquitoes and scale insects.

The availability of limiting nutrients plays a crucial role in shaping communities of endophytes. Moreover, whether fungal endophytes are host-specific remains controversial. We hypothesized that in a harsh and nitrogen (N)-deficient area, diversity and community composition of foliar endophytic fungi (FEFs) varied substantially among plots with experimentally elevated levels of macronutrients, and thus, N availability, instead of host species identity, would have a greater influence in structuring fungal communities at different scales. We also expected an important subset of taxa shared among numerous host species and N gradients to form a community-wide core microbiome. We measured the leaf functional traits and community structures of FEFs of three commonly seen species in an alpine meadow nested with a long-term N fertilization experiment. We found that host plant identity was a powerful factor driving the endophytic fungal community in leaves, even in habitats where productivity was strongly limited by nitrogen (p < 0.001). We also found that within the same host, nitrogen was an important driving force for the composition of the endophytic fungi community (p < 0.05). In addition, the leaf carbon content was the most important functional trait that limited the diversity of endophytic fungi (p < 0.001). Finally, we documented a distinct core microbiome shared among our three focal species and N gradients.

Leptospirosis is a zoonotic infectious disease affecting all vertebrates. It is caused by species of the genus Leptospira, among which are the highly pathogenic L. interrogans. Different mammals can be either resistant or susceptible to the disease which can present a large variety of symptoms. Humans are mostly asymptomatic after infection but can have in some cases symptoms varying from a flu-like syndrome to more severe forms such as Weil's disease, potentially leading to multiorgan failure and death. Similarly, cattle, pigs, and horses can suffer from acute forms of the disease, including morbidity, abortion, and uveitis. On the other hand, mice and rats are resistant to leptospirosis despite chronical colonization of the kidneys, excreting leptospires in urine and contributing to the transmission of the bacteria. To this date, the immune mechanisms that determine the severity of the infection and that confer susceptibility to leptospirosis remain enigmatic. To our interest, differential immune sensing of leptospires through the activation of or escape from pattern recognition receptors (PRRs) by microbe-associated molecular patterns (MAMPs) has recently been described. In this review, we will summarize these findings that suggest that in various hosts, leptospires differentially escape recognition by some Toll-like and NOD-like receptors, including TLR4, TLR5, and NOD1, although TLR2 and NLRP3 responses are conserved independently of the host. Overall, we hypothesize that these innate immune mechanisms could play a role in determining host susceptibility to leptospirosis and suggest a central, yet complex, role for TLR4. [ABSTRACT FROM AUTHOR]

Summary: Feedback between plants and soil microbial communities can be a powerful driver of vegetation dynamics. Plants elicit changes in the soil microbiome that either promote or suppress conspecifics at the same location, thereby regulating population density‐dependence and species co‐existence. Such effects are often attributed to the accumulation of host‐specific antagonistic or beneficial microbiota in the rhizosphere. However, the identity and host‐specificity of the microbial taxa involved are rarely empirically assessed. Here we review the evidence for host‐specificity in plant‐associated microbes and propose that specific plant–soil feedbacks can also be driven by generalists. We outline the potential mechanisms by which generalist microbial pathogens, mutualists and decomposers can generate differential effects on plant hosts and synthesize existing evidence to predict these effects as a function of plant investments into defence, microbial mutualists and dispersal. Importantly, the capacity of generalist microbiota to drive plant–soil feedbacks depends not only on the traits of individual plants but also on the phylogenetic and functional diversity of plant communities. Identifying factors that promote specialization or generalism in plant–microbial interactions and thereby modulate the impact of microbiota on plant performance will advance our understanding of the mechanisms underlying plant–soil feedback and the ways it contributes to plant co‐existence. [ABSTRACT FROM AUTHOR]

Background: Bacterial identification at the strain level is a much-needed, but arduous and challenging task. This study aimed to develop a method for identifying and differentiating individual strains among multiple strains of the same bacterial species. The set used for testing the method consisted of 17 Escherichia coli strains picked from a collection of strains isolated in Germany, Spain, the United Kingdom and Vietnam from humans, cattle, swine, wild boars, and chickens. We targeted unique or rare ORFan genes to address the problem of selective and specific strain identification. These ORFan genes, exclusive to each strain, served as templates for developing strain-specific primers. Results: Most of the experimental strains (14 out of 17) possessed unique ORFan genes that were used to develop strain-specific primers. The remaining three strains were identified by combining a PCR for a rare gene with a selection step for isolating the experimental strains. Multiplex PCR allowed the successful identification of the strains both in vitro in spiked faecal material in addition to in vivo after experimental infections of pigs and recovery of bacteria from faecal material. In addition, primers for qPCR were also developed and quantitative readout from faecal samples after experimental infection was also possible. Conclusions: The method described in this manuscript using strain-specific unique genes to identify single strains in a mixture of strains proved itself efficient and reliable in detecting and following individual strains both in vitro and in vivo, representing a fast and inexpensive alternative to more costly methods. [ABSTRACT FROM AUTHOR]

The global diversity of fungi has been estimated using several different approaches. There is somewhere between 2–11 million estimated species, but the number of formally described taxa is around 150,000, a tiny fraction of the total. In this paper, we examine 12 ascomycete genera as case studies to establish trends in fungal species descriptions, and introduce new species in each genus. To highlight the importance of traditional morpho-molecular methods in publishing new species, we introduce novel taxa in 12 genera that are considered to have low species discovery. We discuss whether the species are likely to be rare or due to a lack of extensive sampling and classification. The genera are Apiospora, Bambusicola, Beltrania, Capronia, Distoseptispora, Endocalyx, Neocatenulostroma, Neodeightonia, Paraconiothyrium, Peroneutypa, Phaeoacremonium and Vanakripa. We discuss host-specificity in selected genera and compare the number of species epithets in each genus with the number of ITS (barcode) sequences deposited in GenBank and UNITE. We furthermore discuss the relationship between the divergence times of these genera with those of their hosts. We hypothesize whether there might be more species in these genera and discuss hosts and habitats that should be investigated for novel species discovery. [ABSTRACT FROM AUTHOR]

Fungi play vital roles in ecosystems as endophytes, pathogens and saprobes. The current estimate of fungal diversity is highly uncertain, ranging from 1.5 to 12 million, but only around 150,000 species have been named and classified to date. Since the introduction of DNA based methods for species identification, the number of newly described taxa has increased from approximately 1000 to around 2000 yearly. This demonstrates the importance of DNA based methods to identify and distinguish species, especially cryptic species. Many novel species from recent studies have been found in historically understudied regions and habitats, but these still represent only a small percentage of the estimated species. In this paper, we examine 16 genera from the top 40 most speciose genera as listed in Species Fungorum as case studies to examine the diversity of taxa in each genus. The genera treated herein are Cercospora, Diaporthe, Meliola, Passalora, Phyllachora, Phyllosticta, Pseudocercospora, Ramularia (ascomycetes) and Cortinarius, Entoloma, Inocybe, Marasmius, Psathyrella, Puccinia, Russula, Uromyces (basidiomycetes). We critically evaluate the number of species in these genera and correlate these numbers with the number of entries in GenBank. We introduce 18 new species Apiospora multiloculata, Candolleomyces thailandensis, Cortinarius acutoproximus, Cortinarius melleoalbus, Cortinarius pacificus, Cortinarius parvoacetosus, Diaporthe guizhouensis, Entoloma pseudosubcorvinum, Inocybe meirensongia, Marasmius albulus, Marasmius obscuroaurantiacus, Meliola camporesii, Phyllachora siamensis, Phyllosticta doitungensis, Picipes yuxiensis, Pseudocercospora vignae, Puccinia maureanui and Russula inornata. We also introduce a new record of Candolleomyces cladii-marisci and Inocybe iringolkavensis. We discuss the genera Colletotrichum and Pleurotus that are speciose, but do not occur in the top 40. We hypothesize whether there might be more species in these genera and discuss why these genera have some of the largest number of species. [ABSTRACT FROM AUTHOR]

Groupers are large predators in the Serranidae family that feed on fish and small invertebrates. Identification of parasitic taxa of groupers was done concerning their morphological and biological characteristics. A total of 30 Cephalopholis sonnerati (Serranidae) specimens were investigated for digenetic trematodes in the Red Sea, Saudi Arabia. Only one bivesiculid species, belonging to the Bivesiculidae family, has been identified, with a prevalence rate of 60% (18/30) among infected fish. The Bivesicula species obtained from the fish host’s intestine is morphologically and morphometric compatible with Bivesicula claviformis, which was previously identified from Epinephelus fasciatus (Serranidae) in North Borneo. In addition, maximum parsimony based on Tamura-Nei model was utilized to determine the phylogeny of the recovered Bivesicula species using partial small subunit ribosomal RNA gene (18S rRNA) and large subunit ribosomal RNA gene (28S rRNA) sequences. The query sequences showed the identities of 99.39% and 94.02% for 18S (AJ287485.1) and 28S rRNA (AY222182.1) of the previously described Bivesicula claviformis, respectively. The present study demonstrated that Bivesicula claviformis is the first reported of this genus as endoparasites from C. sonnerati, as well as providing novel DNA data for this species.

Abstract Background The behaviour of blood-sucking arthropods is a crucial determinant of blood protozoan distribution and hence of host-parasite coevolution, but it is very challenging to study in the wild. The molecular identification of parasite lineages in vectors can be a useful key to understand the behaviour and transmission patterns realised by these vectors. Methods In this study, we collected blackflies around nests of three raptor species in the upper forest canopy in central Europe and examined the presence of vertebrate DNA and haemosporidian parasites in them. We molecularly analysed 156 blackfly individuals, their vertebrate blood meals, and the haemosporidian parasite lineages they carried. Results We identified nine species of Simulium blackflies, largely belonging to the subgenera Nevermannia and Eusimulium. Only 1% of the collected specimens was visibly engorged, and only 4% contained remains of host DNA. However, in 29% of the blackflies Leucocytozoon lineages were identified, which is evidence of a previous blood meal on an avian host. Based on the known vertebrate hosts of the recorded Leucocytozoon lineages, we can infer that large and/or abundant birds, such as thrushes, crows, pigeons, birds of prey, owls and tits are the main targets of ornithophilic blackflies in the canopy. Blackfly species contained similar proportions of host group-specific parasite lineages and thus do not appear to be associated with particular host groups. Conclusions The Leucocytozoon clade infecting thrushes, crows, and pigeons present in most represented blackfly species suggests a lack of association between hosts and blackflies, which can increase the probability of host switches of blood parasites. However, the composition of the simuliid species differed between nests of common buzzards, goshawks and red kites. This segregation can be explained by coinciding habitat preferences between host and vector, and may lead to the fast speciation of Leucocytozoon parasites. Thus, subtle ecological preferences and lack of host preference of vectors in the canopy may enable both parasite diversification and host switches, and enforce a habitat-dependent evolution of avian malaria parasites and related haemosporidia.

Abstract Background In Raphanus sativus (Japanese radish), strain D8 of cucumber mosaic virus (CMV-D8) establishes a systemic infection and induces mild mosaic on upper, non-inoculated leaves, whereas strain Y of CMV (CMV-Y) causes only a local infection in the inoculated leaves. Here, we further analyzed the specific viral factor(s) of CMV-D8 that is (are) indispensable for systemic infection in Japanese radish. Methods To identify which genomic RNA(s) is (are) involved in systemic infection in radish, we carried out a pseudorecombination analysis between CMV-D8 and CMV-Y. With recombination analyses between CMV-D8 and CMV-Y using mutant/recombinant RNA2s, chimeric and point-mutated RNA3s, we identified viral factors that are indispensable for systemic infection. Results Viral RNA2 and RNA3 of CMV-D8 facilitated efficient virus spread into the upper, non-inoculated plant tissues of radish (cv. Tokinashi), but not those of CMV-Y. Recombinant RNA2s demonstrated that the 2b protein (2b) and the C-terminus of the 2a protein (2a) of CMV-D8 have a crucial role in systemic infection. In addition, we used chimeric and point-mutated RNA3s to that Pro17 and Pro129 in the coat protein (CP) of CMV-D8 are involved in efficient systemic infection and that Ser51 in the 3a protein (3a) of CMV-D8 has positive effects on systemic spread. The results suggested that these viral factors facilitate systemic infection of CMV-D8 in Japanese radish. Conclusion The C-terminal region of 2a, the entire region of 2b, and supplementary function of either Ser51 in 3a or Pro17/Pro 129 in CP confer systemic infectivity on CMV-D8 in radish. These results further elucidate the complex interaction of viral proteins of CMV to complete systemic infection as a host-specific manner.

Species in Cymothoidae (Crustacea: Isopoda) are cosmopolitan parasite infesting marine, freshwater and brackish water fishes. In Cymothoidae, Anilocra and Nerocila species have an elongated juvenile stage called the aegathoid stage. A total of 831 Japanese halfbeaks Hyporhamphus sajori (Beloniformes: Hemiramphidae) were collected from 11 sites in Japan. The aegathoid stage was seen infesting a Japanese halfbeak collected from Osaki-Shimojima Island, Kure City, Hiroshima Prefecture, and identified as Anilocra clupei by DNA barcoding using the COI and 16S rRNA sequences. The morphology of this individual was also almost identical to the aegathoid stage of A. clupei in the previous study. The prevalence of the aegathoid stage of A. clupei on Japanese halfbeaks was very low at 0.12％ in all of Japan and 0.93％ in the coast of Osaki-Shimojima Island. Aegathoid stages of A. clupei may have lower host-specificity than adult females, and be able to infest more comprehensive species of fish, which may increase the survivability of the aegathoid stages. [ABSTRACT FROM AUTHOR]

Tropical soda apple (Solanum viarum), first detected in Australia in 2010, is a weed of agricultural significance as it reduces cattle stocking rates and limits stock movement. Gratiana boliviana (Coleoptera: Chrysomelidae) is an approved biological control agent for S. viarum in the United States of America (USA). Although the host specificity of G. boliviana has been extensively tested in the USA, additional no-choice tests were conducted to determine if the beetle is sufficiently host specific for release in Australia. The host test list included Solanum species native to Australia, as well as agriculturally important species that had been tested previously. Both adult and larval no-choice tests indicate that G. boliviana does not perform equally well across the target weed S. viarum and the other plant species included in the tests. Oviposition was observed on only two plant species besides the target weed, with significantly more eggs laid on S. viarum (19.5 ± 0.4 eggs/plant), followed by S. brownii (2 ± 0.4 eggs/plant) and S. melongena (1.8 ± 1.5 eggs/plant). Ninety per cent of eggs laid on S. viarum developed to adults, whereas only one egg laid on S. melongena completed development. Larval no-choice feeding assessments indicate that larval survival and development is highest on S. viarum (80%) followed by S. brownii (30%) and S. melongena (20%) and to a much lesser extent on S. lithophilum (2.5%). Our results contribute to the evaluation of the risk of potential off-target effects by G. boliviana feeding and development on native Australian or agriculturally important Solanum species. [ABSTRACT FROM AUTHOR]

Sonchus oleraceus L. (Asteraceae), an annual species native to Eurasia and northern Africa, is among the most widely distributed plant species on Earth. In Australia, S. oleraceus, is a common weed in disturbed areas such as crop fields, pastures, gardens and roadsides. In agricultural settings, it can dominate fallows and cultivated fields where it uses stored soil moisture and reduces crop yield. This weed has also developed herbicide resistance, predicating the need for alternative management solutions. In this context, we undertook field surveys and preliminary host range studies in the native range of S. oleraceus to determine the feasibility of developing classical biological control solutions for Australia. Fifty-nine phytophagous arthropod species were recorded and nine pathogenic fungi were recovered from disease symptoms. Four arthropod species were selected for initial host-specificity testing based on information available in the literature. Preliminary host-specificity tests were also performed with representative isolate(s) of six of the pathogenic fungi. All these candidate agents were shown in the tests to affect key native species in Australia in the same subtribe as S. oleraceus (i.e. Sonchus hydrophilus and Actites megalocarpus). The results of our investigations suggest that classical biological control may not be a feasible option for the management of S. oleraceus in Australia, and that alternative integrated weed management tactics may need to be pursued to mitigate the impacts of this weed. [ABSTRACT FROM AUTHOR]

The diagnosis of pulmonary tuberculosis (TB) in children remains a significant challenge due to its paucibacillary nature, non-specificity of symptoms and suboptimal sensitivity of available diagnostic methods. In young children particularly, it is difficult to obtain high-quality sputum specimens for testing, with this group the least likely to be diagnosed, while most at risk of severe disease. The World Health Organization (WHO) has prioritized research into rapid biomarker-based tests for TB using easily obtainable non-sputum samples, such as saliva. However, the role of biomarkers in saliva for diagnosing TB in children has not been fully explored. In this mini-review, we discuss the value of saliva as a diagnostic specimen in children given its ready availability and non-invasive nature of collection, and review the literature on the use of host-based biomarkers in saliva for diagnosing active pulmonary TB in adults and children. Based on available data from adult studies, we highlight that combinations of cytokines and other proteins show promise in reaching WHO-endorsed target product profiles for new TB triage tests. Given the lack of pediatric research on host biomarkers in saliva and the differing immune response to TB infection between children and adults, we recommend that pediatric studies are now performed to discover and validate salivary host biosignatures for diagnosing pulmonary TB in children. Future directions for pediatric saliva studies are discussed, with suggestions for technologies that can be applied for salivary biomarker discovery and point-of-care test development.

Ectomycorrhizal fungi establish a mutualistic symbiosis in roots of most woody plants. The molecular underpinning of ectomycorrhizal development was only explored in a few lineages. Here, we characterized the symbiotic transcriptomes of several milkcap species (Lactarius, Russulales) in association with different pine hosts. A time-course study of changes in gene expression during the development of L. deliciosus–Pinus taeda symbiosis identified 6 to 594 differentially expressed fungal genes at various developmental stages. Up- or down-regulated genes are involved in signaling pathways, nutrient transport, cell wall modifications, and plant defenses. A high number of genes coding for secreted proteases, especially sedolisins, were induced during root colonization. In contrast, only a few genes encoding mycorrhiza-induced small secreted proteins were identified. This feature was confirmed in several other Lactarius species in association with various pines. Further comparison among all these species revealed that each Lactarius species encodes a highly specific symbiotic gene repertoire, a feature possibly related to their host-specificity. This study provides insights on the genetic basis of symbiosis in an ectomycorrhizal order, the Russulales, which was not investigated so far.

The relationship between entomopathogenic fungi and their insect hosts is a classic example of the co-evolutionary arms race between pathogen and target host. The present review describes the entomopathogenic potential of Chytridiomycota and Blastocladiomycota fungi, and two groups of fungal allies: Oomycota and Microsporidia. The Oomycota (water moulds) are considered as a model biological control agent of mosquito larvae. Due to their shared ecological and morphological similarities, they had long been considered a part of the fungal kingdom; however, phylogenetic studies have since placed this group within the Straminipila. The Microsporidia are parasites of economically-important insects, including grasshoppers, lady beetles, bumblebees, colorado potato beetles and honeybees. They have been found to display some fungal characteristics, and phylogenetic studies suggest that they are related to fungi, either as a basal branch or sister group. The Blastocladiomycota and Chytridiomycota, named the lower fungi, historically were described together; however, molecular phylogenetic and ultrastructural research has classified them in their own phylum. They are considered parasites of ants, and of the larval stages of black flies, mosquitoes and scale insects. [ABSTRACT FROM AUTHOR]

Ectomycorrhizal fungi establish a mutualistic symbiosis in roots of most woody plants. The molecular underpinning of ectomycorrhizal development was only explored in a few lineages. Here, we characterized the symbiotic transcriptomes of several milkcap species (Lactarius , Russulales) in association with different pine hosts. A time-course study of changes in gene expression during the development of L. deliciosus–Pinus taeda symbiosis identified 6 to 594 differentially expressed fungal genes at various developmental stages. Up- or down-regulated genes are involved in signaling pathways, nutrient transport, cell wall modifications, and plant defenses. A high number of genes coding for secreted proteases, especially sedolisins, were induced during root colonization. In contrast, only a few genes encoding mycorrhiza-induced small secreted proteins were identified. This feature was confirmed in several other Lactarius species in association with various pines. Further comparison among all these species revealed that each Lactarius species encodes a highly specific symbiotic gene repertoire, a feature possibly related to their host-specificity. This study provides insights on the genetic basis of symbiosis in an ectomycorrhizal order, the Russulales, which was not investigated so far. [ABSTRACT FROM AUTHOR]

The soft ticks (Ixodida: Argasidae) are ectoparasites of terrestrial vertebrates with a wide geographic distribution, occurring on all continents. These ticks are obligate blood-feeders, most of them show high degrees of host-specialization and several species in arid and tropical regions are important parasites of livestock and men. Species commonly occurring on domestic animals and man are generally well-known, with many studies focusing on their ecology, distribution or vectorial role. However, wildlife-specialist soft ticks are less studied. Nearly half of all soft tick species are bat specialists, with five species (Carios vespertilionis, Chiropterargas boueti, Chiropterargas confusus, Reticulinasus salahi, and Secretargas transgariepinus) occurring in the Western Palearctic. There is no comprehensive study on the distribution, hosts or pathogens in these soft ticks, although most species were shown to carry several viral, bacterial, or protozoan pathogens and also to occasionally infest humans. Based on a literature survey and 1,120 distinct georeferenced records, we present here the geographical range, host selection and vectorial potential for bat-specialist soft ticks occurring in the Western Palearctic (chiefly Europe, North Africa, and the Middle East). Carios vespertilionis shows the largest distribution range and was found on most host species, being ubiquitous wherever crevice-roosting bats occur. All the other species were located only in areas with Mediterranean climate, with Ch. boueti, Chiropteraragas confusus, and R. salahi are missing entirely from Europe. These three species have a host spectrum of bats roosting primarily in caves, while S. transgariepinus and Ca. vespertilionis is feeding primarily on crevice-roosting bat species. All but one of these soft tick species are known to feed on humans and may be vectors of important disease agents (Rickettsia spp., Borrelia spp., Bartonella spp., Ehrlichia spp., Babesia spp., several nairo-, and flaviviruses). As several crevice-roosting bat species show a continuous adaptation to human-altered areas, with certain species becoming common city-dwellers in the Western Palearctic, the study of bat specialist soft ticks is also important from an epidemiologic point of view.