Artículos de revistas: "Host-Symbiont specificity"

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MATTHEWS, ALIX E., THAN J. BOVES, ANDREW D. SWEET, ELIZABETH M. AMES, LESLEY P. BULLUCK, ERIK I. JOHNSON, MATTHEW JOHNSON et al. "Population genomics of avian feather mites with contrasting host specificities". Zoosymposia 22 (30 de noviembre de 2022): 47. http://dx.doi.org/10.11646/zoosymposia.22.1.17.

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Host specificity is a key element to our understanding of symbiont diversification and is driven by multiple macro- and microevolutionary processes. Broad scale (e.g., species-level) studies can uncover relevant processes such as cospeciation and host-switching that shape host-symbiont evolutionary histories.

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Rahat, M. y V. Reich. "Algal endosymbiosis in brown hydra: host/symbiont specificity". Journal of Cell Science 86, n.º 1 (1 de diciembre de 1986): 273–86. http://dx.doi.org/10.1242/jcs.86.1.273.

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Host/symbiont specificity has been investigated in non-symbiotic and aposymbiotic brown and green hydra infected with various free-living and symbiotic species and strains of Chlorella and Chlorococcum. Morphology and ultrastructure of the symbioses obtained have been compared. Aposymbiotic Swiss Hydra viridis and Japanese H. magnipapillata served as controls. In two strains of H. attenuata stable hereditary symbioses were obtained with Chlorococcum isolated from H. magnipapillata. In one strain of H. vulgaris, in H. oligactis and in aposymbiotic H. viridis chlorococci persisted for more than a week. Eight species of free-living Chlorococcum, 10 symbiotic and 10 free-living strains of Chlorella disappeared from the brown hydra within 1–2 days. In H. magnipapillata there was a graded distribution of chlorococci along the polyps. In hypostomal cells there were greater than 30 algae/cell while in endodermal cells of the mid-section or peduncle less than 10 algae/cell were found. In H. attenuata the algal distribution was irregular, there were up to five chlorocci/cell, and up to 20 cells/hydra hosted algae. In the dark most cells of Chlorococcum disappeared from H. magnipapillata and aposymbiotic hydra were obtained. Chlorococcum is thus an obligate phototroph, and host-dependent heterotrophy is not required for the preservation of a symbiosis. The few chlorococci that survived in the dark seem to belong to a less-demanding physiological strain. In variance with known Chlorella/H. viridis endosymbioses the chlorococci in H. magnipapillata and H. attenuata were tightly enveloped in the vacuolar membrane of the hosting cells with no visible perialgal space. Chlorococcum reproduced in these vacuoles and up to eight daughter cells were found within the same vacuole. We suggest that the graded or scant distribution of chlorococci in the various brown hydra, their inability to live in H. viridis and the inability of the various chlorellae to live in brown hydra are the result of differences in nutrients available to the algae in the respective hosting cells. We conclude that host/symbiont specificity and the various forms of interrelations we show in green and brown hydra with chlorococci and chlorellae are based on nutritional-ecological factors. These interrelations demonstrate successive stages in the evolution of stable obligatoric symbioses from chance encounters of preadapted potential cosymbionts.

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Mandel, Mark J. "Models and approaches to dissect host–symbiont specificity". Trends in Microbiology 18, n.º 11 (noviembre de 2010): 504–11. http://dx.doi.org/10.1016/j.tim.2010.07.005.

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Itoh, Hideomi, Seonghan Jang, Kazutaka Takeshita, Tsubasa Ohbayashi, Naomi Ohnishi, Xian-Ying Meng, Yasuo Mitani y Yoshitomo Kikuchi. "Host–symbiont specificity determined by microbe–microbe competition in an insect gut". Proceedings of the National Academy of Sciences 116, n.º 45 (21 de octubre de 2019): 22673–82. http://dx.doi.org/10.1073/pnas.1912397116.

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Despite the omnipresence of specific host–symbiont associations with acquisition of the microbial symbiont from the environment, little is known about how the specificity of the interaction evolved and is maintained. The bean bug Riptortus pedestris acquires a specific bacterial symbiont of the genus Burkholderia from environmental soil and harbors it in midgut crypts. The genus Burkholderia consists of over 100 species, showing ecologically diverse lifestyles, and including serious human pathogens, plant pathogens, and nodule-forming plant mutualists, as well as insect mutualists. Through infection tests of 34 Burkholderia species and 18 taxonomically diverse bacterial species, we demonstrate here that nonsymbiotic Burkholderia and even its outgroup Pandoraea could stably colonize the gut symbiotic organ and provide beneficial effects to the bean bug when inoculated on aposymbiotic hosts. However, coinoculation revealed that the native symbiont always outcompeted the nonnative bacteria inside the gut symbiotic organ, explaining the predominance of the native Burkholderia symbiont in natural bean bug populations. Hence, the abilities for colonization and cooperation, usually thought of as specific traits of mutualists, are not unique to the native Burkholderia symbiont but, to the contrary, competitiveness inside the gut is a derived trait of the native symbiont lineage only and was thus critical in the evolution of the insect gut symbiont.

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Kwiatkowski, Marek, Jan Engelstädter y Christoph Vorburger. "On Genetic Specificity in Symbiont-Mediated Host-Parasite Coevolution". PLoS Computational Biology 8, n.º 8 (30 de agosto de 2012): e1002633. http://dx.doi.org/10.1371/journal.pcbi.1002633.

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Garcia-Cuetos, Lydia, Xavier Pochon y Jan Pawlowski. "Molecular Evidence for Host–Symbiont Specificity in Soritid Foraminifera". Protist 156, n.º 4 (diciembre de 2005): 399–412. http://dx.doi.org/10.1016/j.protis.2005.08.003.

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Osvatic, Jay T., Laetitia G. E. Wilkins, Lukas Leibrecht, Matthieu Leray, Sarah Zauner, Julia Polzin, Yolanda Camacho et al. "Global biogeography of chemosynthetic symbionts reveals both localized and globally distributed symbiont groups". Proceedings of the National Academy of Sciences 118, n.º 29 (16 de julio de 2021): e2104378118. http://dx.doi.org/10.1073/pnas.2104378118.

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In the ocean, most hosts acquire their symbionts from the environment. Due to the immense spatial scales involved, our understanding of the biogeography of hosts and symbionts in marine systems is patchy, although this knowledge is essential for understanding fundamental aspects of symbiosis such as host–symbiont specificity and evolution. Lucinidae is the most species-rich and widely distributed family of marine bivalves hosting autotrophic bacterial endosymbionts. Previous molecular surveys identified location-specific symbiont types that “promiscuously” form associations with multiple divergent cooccurring host species. This flexibility of host–microbe pairings is thought to underpin their global success, as it allows hosts to form associations with locally adapted symbionts. We used metagenomics to investigate the biodiversity, functional variability, and genetic exchange among the endosymbionts of 12 lucinid host species from across the globe. We report a cosmopolitan symbiont species, Candidatus Thiodiazotropha taylori, associated with multiple lucinid host species. Ca. T. taylori has achieved more success at dispersal and establishing symbioses with lucinids than any other symbiont described thus far. This discovery challenges our understanding of symbiont dispersal and location-specific colonization and suggests both symbiont and host flexibility underpin the ecological and evolutionary success of the lucinid symbiosis.

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Hudatwi, Mu'alimah, Diah permata Wijayanti, Ambariyanto Ambariyanto y Michio Hidaka. "Fitness of Cassiopea polyps Inoculated with Different Types of Symbionts". ILMU KELAUTAN: Indonesian Journal of Marine Sciences 27, n.º 2 (12 de enero de 2022): 151–58. http://dx.doi.org/10.14710/ik.ijms.27.2.151-158.

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The specificity of the relationship between cnidarian hosts and symbiotic dinoflagellates (zooxanthellae) differs among host species. Some cnidarian hosts can establish symbiotic relationship with various types of zooxanthellae, while others exhibit high fidelity to specific symbiont type. It is not known how compatibility or specificity of the relationship is determined. We hypothesized that some cnidarian hosts select symbiont type that leads to highest fitness when the host is flexible with symbiont type and more than one types of symbionts are available. As a first step to study this possibility, compatibility of clonal polyps of Cassiopea sp. with six strains of cultured zooxanthellae and the fitness of the host associated with different types of symbionts were studied. Polyp diameter was measured and the number of asexual buds were calculated as a measure of host fitness. The number of zooxanthellae in host and in asexual buds was also measured as a measure of symbiont fitness. Three strains KB8 (clade A), Y106 (clade A), and K100 (clade B) were compatible with the Cassiopea polyps, while other three strains, Y103 (clade C), K111 (clade D), and K102 (clade F) were incompatible. No clear difference in the fitness was found among the polyps inoculated with compatible and incompatible symbiont strains. In one experiment, a compatible strain Y106 seemed to decrease host fitness, but this should be checked by further studies. This study suggests that feeding regimes and long observation period might be important when fitness of hosts associated with different types of symbionts is investigated.

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Seah, Brandon K. B., Thomas Schwaha, Jean-Marie Volland, Bruno Huettel, Nicole Dubilier y Harald R. Gruber-Vodicka. "Specificity in diversity: single origin of a widespread ciliate-bacteria symbiosis". Proceedings of the Royal Society B: Biological Sciences 284, n.º 1858 (12 de julio de 2017): 20170764. http://dx.doi.org/10.1098/rspb.2017.0764.

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Symbioses between eukaryotes and sulfur-oxidizing (thiotrophic) bacteria have convergently evolved multiple times. Although well described in at least eight classes of metazoan animals, almost nothing is known about the evolution of thiotrophic symbioses in microbial eukaryotes (protists). In this study, we characterized the symbioses between mouthless marine ciliates of the genus Kentrophoros , and their thiotrophic bacteria, using comparative sequence analysis and fluorescence in situ hybridization. Ciliate small-subunit rRNA sequences were obtained from 17 morphospecies collected in the Mediterranean and Caribbean, and symbiont sequences from 13 of these morphospecies. We discovered a new Kentrophoros morphotype where the symbiont-bearing surface is folded into pouch-like compartments, illustrating the variability of the basic body plan. Phylogenetic analyses revealed that all investigated Kentrophoros belonged to a single clade, despite the remarkable morphological diversity of these hosts. The symbionts were also monophyletic and belonged to a new clade within the Gammaproteobacteria, with no known cultured representatives. Each host morphospecies had a distinct symbiont phylotype, and statistical analyses revealed significant support for host–symbiont codiversification. Given that these symbioses were collected from two widely separated oceans, our results indicate that symbiotic associations in unicellular hosts can be highly specific and stable over long periods of evolutionary time.

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Ashen, Jon B. y Lynda J. Goff. "Molecular and Ecological Evidence for Species Specificity and Coevolution in a Group of Marine Algal-Bacterial Symbioses". Applied and Environmental Microbiology 66, n.º 7 (1 de julio de 2000): 3024–30. http://dx.doi.org/10.1128/aem.66.7.3024-3030.2000.

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ABSTRACT The phylogenetic relationships of bacterial symbionts from three gall-bearing species in the marine red algal genusPrionitis (Rhodophyta) were inferred from 16S rDNA sequence analysis and compared to host phylogeny also inferred from sequence comparisons (nuclear ribosomal internal-transcribed-spacer region). Gall formation has been described previously on two species ofPrionitis, P. lanceolata (from central California) and P. decipiens (from Peru). This investigation reports gall formation on a third related host,Prionitis filiformis. Phylogenetic analyses based on sequence comparisons place the bacteria as a single lineage within theRoseobacter grouping of the α subclass of the divisionProteobacteria (99.4 to 98.25% sequence identity among phylotypes). Comparison of symbiont and host molecular phylogenies confirms the presence of three gall-bearing algal lineages and is consistent with the hypothesis that these red seaweeds and their bacterial symbionts are coevolving. The species specificity of these associations was investigated in nature by whole-cell hybridization of gall bacteria and in the laboratory by using cross-inoculation trials. Whole-cell in situ hybridization confirmed that a single bacterial symbiont phylotype is present in galls on each host. In laboratory trials, bacterial symbionts were incapable of inducing galls on alternate hosts (including two non-gall-bearing species). Symbiont-host specificity in Prionitis gall formation indicates an effective ecological separation between these closely related symbiont phylotypes and provides an example of a biological context in which to consider the organismic significance of 16S rDNA sequence variation.

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Huguet, Valérie, Manolo Gouy, Philippe Normand, Jeff F. Zimpfer y Maria P. Fernandez. "Molecular phylogeny of Myricaceae: a reexamination of host–symbiont specificity". Molecular Phylogenetics and Evolution 34, n.º 3 (marzo de 2005): 557–68. http://dx.doi.org/10.1016/j.ympev.2004.11.018.

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Matthews, Jennifer L., Camerron M. Crowder, Clinton A. Oakley, Adrian Lutz, Ute Roessner, Eli Meyer, Arthur R. Grossman, Virginia M. Weis y Simon K. Davy. "Optimal nutrient exchange and immune responses operate in partner specificity in the cnidarian-dinoflagellate symbiosis". Proceedings of the National Academy of Sciences 114, n.º 50 (20 de noviembre de 2017): 13194–99. http://dx.doi.org/10.1073/pnas.1710733114.

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The relationship between corals and dinoflagellates of the genusSymbiodiniumis fundamental to the functioning of coral ecosystems. It has been suggested that reef corals may adapt to climate change by changing their dominant symbiont type to a more thermally tolerant one, although the capacity for such a shift is potentially hindered by the compatibility of different host-symbiont pairings. Here we combined transcriptomic and metabolomic analyses to characterize the molecular, cellular, and physiological processes that underlie this compatibility, with a particular focus onSymbiodinium trenchii, an opportunistic, thermally tolerant symbiont that flourishes in coral tissues after bleaching events. Symbiont-free individuals of the sea anemoneExaiptasia pallida(commonly referred to as Aiptasia), an established model system for the study of the cnidarian-dinoflagellate symbiosis, were colonized with the “normal” (homologous) symbiontSymbiodinium minutumand the heterologousS. trenchii. Analysis of the host gene and metabolite expression profiles revealed that heterologous symbionts induced an expression pattern intermediate between the typical symbiotic state and the aposymbiotic state. Furthermore, integrated pathway analysis revealed that increased catabolism of fixed carbon stores, metabolic signaling, and immune processes occurred in response to the heterologous symbiont type. Our data suggest that both nutritional provisioning and the immune response induced by the foreign “invader” are important factors in determining the capacity of corals to adapt to climate change through the establishment of novel symbioses.

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McCuaig, Bonita, France Liboiron y Suzanne C. Dufour. "The bivalveThyasiracf.gouldihosts chemoautotrophic symbiont populations with strain level diversity". PeerJ 5 (26 de julio de 2017): e3597. http://dx.doi.org/10.7717/peerj.3597.

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Invertebrates from various marine habitats form nutritional symbioses with chemosynthetic bacteria. In chemosynthetic symbioses, both the mode of symbiont transmission and the site of bacterial housing can affect the composition of the symbiont population. Vertically transmitted symbionts, as well as those hosted intracellularly, are more likely to form clonal populations within their host. Conversely, symbiont populations that are environmentally acquired and extracellular may be more likely to be heterogeneous/mixed within host individuals, as observed in some mytilid bivalves. The symbionts of thyasirid bivalves are also extracellular, but limited 16S rRNA sequencing data suggest that thyasirid individuals contain uniform symbiont populations. In a recent study,Thyasiracf.gouldiindividuals from Bonne Bay, Newfoundland, Canada were found to host one of three 16S rRNA phylotypes of sulfur-oxidizing gammaproteobacteria, suggesting environmental acquisition of symbionts and some degree of site-specificity. Here, we use Sanger sequencing of both 16S RNA and the more variable ribulose-1,5-bisphosphate carboxylase (RuBisCO) PCR products to further examineThyasiracf.gouldisymbiont diversity at the scale of host individuals, as well as to elucidate any temporal or spatial patterns in symbiont diversity within Bonne Bay, and relationships with host OTU or size. We obtained symbiont 16S rRNA and RuBisCO Form II sequences from 54 and 50 host individuals, respectively, during nine sampling trips to three locations over four years. Analyses uncovered the same three closely related 16S rRNA phylotypes obtained previously, as well as three divergent RuBisCO phylotypes; these were found in various pair combinations within host individuals, suggesting incidents of horizontal gene transfer during symbiont evolution. While we found no temporal patterns in phylotype distribution or relationships with host OTU or size, some spatial effects were noted, with some phylotypes only found within particular sampling sites. The sequencing also revealed symbiont populations within individual hosts that appeared to be a mixture of different phylotypes, based on multiple base callings at divergent sites. This work provides further evidence thatThyasiracf.gouldiacquires its symbionts from the environment, and supports the theory that hosts can harbour symbiont populations consisting of multiple, closely related bacterial phylotypes.

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McLean, Ailsa H. C. y H. Charles J. Godfray. "Evidence for specificity in symbiont-conferred protection against parasitoids". Proceedings of the Royal Society B: Biological Sciences 282, n.º 1811 (22 de julio de 2015): 20150977. http://dx.doi.org/10.1098/rspb.2015.0977.

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Many insects harbour facultative symbiotic bacteria, some of which have been shown to provide resistance against natural enemies. One of the best-known protective symbionts is Hamiltonella defensa , which in pea aphid ( Acyrthosiphon pisum ) confers resistance against attack by parasitoid wasps in the genus Aphidius (Braconidae). We asked (i) whether this symbiont also confers protection against a phylogenetically distant group of parasitoids (Aphelinidae) and (ii) whether there are consistent differences in the effects of bacteria found in pea aphid biotypes adapted to different host plants. We found that some H. defensa strains do provide protection against an aphelinid parasitoid Aphelinus abdominalis. Hamiltonella defensa from the Lotus biotype provided high resistance to A. abdominalis and moderate to low resistance to Aphidius ervi , while the reverse was seen from Medicago biotype isolates. Aphids from Ononis showed no evidence of symbiont-mediated protection against either wasp species and were relatively vulnerable to both. Our results may reflect the different selection pressures exerted by the parasitoid community on aphids feeding on different host plants, and could help explain the maintenance of genetic diversity in bacterial symbionts.

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Dunlap, Paul V., Jennifer C. Ast, Seishi Kimura, Atsushi Fukui, Tetsuo Yoshino y Hiromitsu Endo. "Phylogenetic analysis of host?symbiont specificity and codivergence in bioluminescent symbioses". Cladistics 23, n.º 5 (octubre de 2007): 507–32. http://dx.doi.org/10.1111/j.1096-0031.2007.00157.x.

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Jones, B. W. y M. K. Nishiguchi. "Differentially expressed genes reveal adaptations between free-living and symbiotic niches of Vibrio fischeri in a fully established mutualism". Canadian Journal of Microbiology 52, n.º 12 (1 de diciembre de 2006): 1218–27. http://dx.doi.org/10.1139/w06-088.

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A major force driving in the innovation of mutualistic symbioses is the number of adaptations that both organisms must acquire to provide overall increased fitness for a successful partnership. Many of these symbioses are relatively dependent on the ability of the symbiont to locate a host (specificity), as well as provide some novel capability upon colonization. The mutualism between sepiolid squids and members of the Vibrionaceae is a unique system in which development of the symbiotic partnership has been studied in detail, but much remains unknown about the genetics of symbiont colonization and persistence within the host. Using a method that captures exclusively expressed transcripts in either free-living or host-associated strains of Vibrio fischeri, we identified and verified expression of genes differentially expressed in both states from two symbiotic strains of V. fischeri. These genes provide a glimpse into the microhabitat V. fischeri encounters in both free-living seawater and symbiotic host light organ-associated habitats, providing insight into the elements necessary for local adaptation and the evolution of host specificity in this unique mutualism.Key words: Vibrionaceae, gene expression, Sepiolidae, Euprymna, SCOTS.

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Herrera, Marcela, Shannon G. Klein, Sara Campana, Jit Ern Chen, Arun Prasanna, Carlos M. Duarte y Manuel Aranda. "Temperature transcends partner specificity in the symbiosis establishment of a cnidarian". ISME Journal 15, n.º 1 (15 de septiembre de 2020): 141–53. http://dx.doi.org/10.1038/s41396-020-00768-y.

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AbstractCoral reef research has predominantly focused on the effect of temperature on the breakdown of coral-dinoflagellate symbioses. However, less is known about how increasing temperature affects the establishment of new coral-dinoflagellate associations. Inter-partner specificity and environment-dependent colonization are two constraints proposed to limit the acquisition of more heat tolerant symbionts. Here, we investigated the symbiotic dynamics of various photosymbionts in different host genotypes under “optimal” and elevated temperature conditions. To do this, we inoculated symbiont-free polyps of the sea anemone Exaiptasia pallida originating from Hawaii (H2), North Carolina (CC7), and the Red Sea (RS) with the same mixture of native symbiont strains (Breviolum minutum, Symbiodinium linucheae, S. microadriaticum, and a Breviolum type from the Red Sea) at 25 and 32 °C, and assessed their ITS2 composition, colonization rates, and PSII photochemical efficiency (Fv/Fm). Symbiont communities across thermal conditions differed significantly for all hosts, suggesting that temperature rather than partner specificity had a stronger effect on symbiosis establishment. Overall, we detected higher abundances of more heat resistant Symbiodiniaceae types in the 32 °C treatments. Our data further showed that PSII photophysiology under elevated temperature improved with thermal pre-exposure (i.e., higher Fv/Fm), yet, this effect depended on host genotype and was influenced by active feeding as photochemical efficiency dropped in response to food deprivation. These findings highlight the role of temperature and partner fidelity in the establishment and performance of symbiosis and demonstrate the importance of heterotrophy for symbiotic cnidarians to endure and recover from stress.

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Suzuki, Yohey, Shigeaki Kojima, Takenori Sasaki, Masae Suzuki, Takashi Utsumi, Hiromi Watanabe, Hidetoshi Urakawa et al. "Host-Symbiont Relationships in Hydrothermal Vent Gastropods of the Genus Alviniconcha from the Southwest Pacific". Applied and Environmental Microbiology 72, n.º 2 (febrero de 2006): 1388–93. http://dx.doi.org/10.1128/aem.72.2.1388-1393.2006.

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ABSTRACT Hydrothermal vent gastropods of the genus Alviniconcha are unique among metazoans in their ability to derive their nutrition from chemoautotrophic γ- and ε-proteobacterial endosymbionts. Although host-symbiont relationships in Alviniconcha gastropods from the Central Indian Ridge in the Indian Ocean and the Mariana Trough in the Western Pacific have been studied extensively, host-symbiont relationships in Alviniconcha gastropods from the Southwest Pacific remain largely unknown. Phylogenetic analysis using mitochondrial cytochrome c oxidase subunit I gene sequences of host gastropods from the Manus, North Fiji, and Lau Back-Arc Basins in the Southwest Pacific has revealed a new host lineage in a Alviniconcha gastropod from the Lau Basin and the occurrence of the host lineage Alviniconcha sp. type 2 in the Manus Basin. Based on 16S rRNA gene sequences of bacterial endosymbionts, two γ-proteobacterial lineages and one ε-proteobacterial lineage were identified in the present study. The carbon isotopic compositions of the biomass and fatty acids of the gastropod tissues suggest that the γ- and ε-proteobacterial endosymbionts mediate the Calvin-Benson cycle and the reductive tricarboxylic acid cycle, respectively, for their chemoautotrophic growth. Coupling of the host and symbiont lineages from the three Southwest Pacific basins revealed that each of the Alviniconcha lineages harbors different bacterial endosymbionts belonging to either the γ- or ε-Proteobacteria. The host specificity exhibited in symbiont selection provides support for the recognition of each of the host lineages as a distinct species. The results from the present study also suggest the possibility that Alviniconcha sp. types 1 and 2 separately inhabit hydrothermal vent sites approximately 120 m apart in the North Fiji Basin and 500 m apart in the Manus Basin.

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Nobre, Tânia. "Olive fruit fly and its obligate symbiont Candidatus Erwinia dacicola: Two new symbiont haplotypes in the Mediterranean basin". PLOS ONE 16, n.º 9 (8 de septiembre de 2021): e0256284. http://dx.doi.org/10.1371/journal.pone.0256284.

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The olive fruit fly, specialized to become monophagous during several life stages, remains the most important olive tree pest with high direct production losses, but also affecting the quality, composition, and inherent properties of the olives. Thought to have originated in Africa is nowadays present wherever olive groves are grown. The olive fruit fly evolved to harbor a vertically transmitted and obligate bacterial symbiont -Candidatus Erwinia dacicola- leading thus to a tight evolutionary history between olive tree, fruit fly and obligate, vertical transmitted symbiotic bacterium. Considering this linkage, the genetic diversity (at a 16S fragment) of this obligate symbiont was added in the understanding of the distribution pattern of the holobiont at nine locations throughout four countries in the Mediterranean Basin. This was complemented with mitochondrial (four mtDNA fragments) and nuclear (ten microsatellites) data of the host. We focused on the previously established Iberian cluster for the B. oleae structure and hypothesised that the Tunisian samples would fall into a differentiated cluster. From the host point of view, we were unable to confirm this hypothesis. Looking at the symbiont, however, two new 16S haplotypes were found exclusively in the populations from Tunisia. This finding is discussed in the frame of host-symbiont specificity and transmission mode. To understand olive fruit fly population diversity and dispersion, the dynamics of the symbiont also needs to be taken into consideration, as it enables the fly to, so efficiently and uniquely, exploit the olive fruit resource.

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Tseng, Shu-Ping, Po-Wei Hsu, Chih-Chi Lee, James K. Wetterer, Sylvain Hugel, Li-Hsin Wu, Chow-Yang Lee, Tsuyoshi Yoshimura y Chin-Cheng Scotty Yang. "Evidence for Common Horizontal Transmission of Wolbachia among Ants and Ant Crickets: Kleptoparasitism Added to the List". Microorganisms 8, n.º 6 (27 de mayo de 2020): 805. http://dx.doi.org/10.3390/microorganisms8060805.

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While Wolbachia, an intracellular bacterial symbiont, is primarily transmitted maternally in arthropods, horizontal transmission between species has been commonly documented. We examined kleptoparasitism as a potential mechanism for Wolbachia horizontal transmission, using ant crickets and their host ants as the model system. We compared prevalence and diversity of Wolbachia across multiple ant cricket species with different degrees of host specificity/integration level. Our analyses revealed at least three cases of inter-ordinal Wolbachia transfer among ant and ant crickets, and also showed that ant cricket species with high host-integration and host-specificity tend to harbor a higher Wolbachia prevalence and diversity than other types of ant crickets. This study provides empirical evidence that distribution of Wolbachia across ant crickets is largely attributable to horizontal transmission, but also elucidates the role of intimate ecological association in successful Wolbachia horizontal transmission.

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Zamborsky, D. J. y M. K. Nishiguchi. "Phylogeographical Patterns among Mediterranean Sepiolid Squids and TheirVibrioSymbionts: Environment Drives Specificity among Sympatric Species". Applied and Environmental Microbiology 77, n.º 2 (12 de noviembre de 2010): 642–49. http://dx.doi.org/10.1128/aem.02105-10.

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ABSTRACTBobtail squid from the generaSepiolaandRondeletiola(Cephalopoda: Sepiolidae) form mutualistic associations with luminous Gram-negative bacteria (Gammaproteobacteria:Vibrionaceae) from the generaVibrioandPhotobacterium. Symbiotic bacteria proliferate inside a bilobed light organ until they are actively expelled by the host into the surrounding environment on a diel basis. This event results in a dynamic symbiont population with the potential to establish the symbiosis with newly hatched sterile (axenic) juvenile sepiolids. In this study, we examined the genetic diversity found in populations of sympatric sepiolid squid species and their symbionts by the use of nested clade analysis with multiple gene analyses. Variation found in the distribution of different species of symbiotic bacteria suggests a strong influence of abiotic factors in the local environment, affecting bacterial distribution among sympatric populations of hosts. These abiotic factors include temperature differences incurred by a shallow thermocline, as well as a lack of strong coastal water movement accompanied by seasonal temperature changes in overlapping niches. Host populations are stable and do not appear to have a significant role in the formation of symbiont populations relative to their distribution across the Mediterranean Sea. Additionally, all squid species examined (Sepiola affinis,S. robusta,S. ligulata,S. intermedia, andRondeletiola minor) are genetically distinct from one another regardless of location and demonstrate very little intraspecific variation within species. These findings suggest that physical boundaries and distance in relation to population size, and not host specificity, are important factors in limiting or defining gene flow within sympatric marine squids and their associated bacterial symbionts in the Mediterranean Sea.

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Weigel, Brooke L. y Patrick M. Erwin. "Intraspecific Variation in Microbial Symbiont Communities of the Sun Sponge, Hymeniacidon heliophila, from Intertidal and Subtidal Habitats". Applied and Environmental Microbiology 82, n.º 2 (13 de noviembre de 2015): 650–58. http://dx.doi.org/10.1128/aem.02980-15.

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ABSTRACTSponges host diverse and complex communities of microbial symbionts that display a high degree of host specificity. The microbiomes of conspecific sponges are relatively constant, even across distant locations, yet few studies have directly examined the influence of abiotic factors on intraspecific variation in sponge microbial community structure. The contrast between intertidal and subtidal environments is an ideal system to assess the effect of environmental variation on sponge-microbe symbioses, producing two drastically different environments on a small spatial scale. Here, we characterized the microbial communities of individual intertidal and subtidalHymeniacidonheliophilasponges, ambient seawater, and sediment from a North Carolina oyster reef habitat by partial (Illumina sequencing) and nearly full-length (clone libraries) 16S rRNA gene sequence analyses. Clone library sequences were compared toH. heliophilasymbiont communities from the Gulf of Mexico and Brazil, revealing strong host specificity of dominant symbiont taxa across expansive geographic distances. Sediment and seawater samples yielded clearly distinct microbial communities from those found inH. heliophila. Despite the close proximity of the sponges sampled, significant differences between subtidal and intertidal sponges in the diversity, structure, and composition of their microbial communities were detected. Differences were driven by changes in the relative abundance of a few dominant microbial symbiont taxa, as well as the presence or absence of numerous rare microbial taxa. These findings suggest that extreme abiotic fluctuations, such as periodic air exposure in intertidal habitats, can drive intraspecific differences in complex host-microbe symbioses.

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23

Powell, Elijah, Nalin Ratnayeke y Nancy A. Moran. "Strain diversity and host specificity in a specialized gut symbiont of honeybees and bumblebees". Molecular Ecology 25, n.º 18 (septiembre de 2016): 4461–71. http://dx.doi.org/10.1111/mec.13787.

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24

Sepp, Siim‐Kaarel, John Davison, Teele Jairus, Martti Vasar, Mari Moora, Martin Zobel y Maarja Öpik. "Non‐random association patterns in a plant–mycorrhizal fungal network reveal host–symbiont specificity". Molecular Ecology 28, n.º 2 (10 de diciembre de 2018): 365–78. http://dx.doi.org/10.1111/mec.14924.

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25

Flemming, Felicitas E., Alexey Potekhin, Thomas Pröschold y Martina Schrallhammer. "Algal Diversity in Paramecium bursaria: Species Identification, Detection of Choricystis parasitica, and Assessment of the Interaction Specificity". Diversity 12, n.º 8 (23 de julio de 2020): 287. http://dx.doi.org/10.3390/d12080287.

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The ‘green’ ciliate Paramecium bursaria lives in mutualistic symbiosis with green algae belonging to the species Chlorella variabilis or Micractinium conductrix. We analysed the diversity of algal endosymbionts and their P. bursaria hosts in nine strains from geographically diverse origins. Therefore, their phylogenies using different molecular markers were inferred. The green paramecia belong to different syngens of P. bursaria. The intracellular algae were assigned to Chl. variabilis, M. conductrix or, surprisingly, Choricystis parasitica. This usually free-living alga co-occurs with M. conductrix in the host’s cytoplasm. Addressing the potential status of Chor. parasitica as second additional endosymbiont, we determined if it is capable of symbiosis establishment and replication within a host cell. Symbiont-free P. bursaria were generated by cycloheximid treatment. Those aposymbiotic P. bursaria were used for experimental infections to investigate the symbiosis specificity not only between P. bursaria and Chor. parasitica but including also Chl. variabilis and M. conductrix. For each algae we observed the uptake and incorporation in individual perialgal vacuoles. These host-symbiont associations are stable since more than five months. Thus, Chor. parasitica and P. bursaria can form an intimate and long-term interaction. This study provides new insights into the diversity of P. bursaria algal symbionts.

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26

Wooding, Amy L., Michael J. Wingfield, Brett P. Hurley, Jeffrey R. Garnas, Peter de Groot y Bernard Slippers. "Lack of fidelity revealed in an insect–fungal mutualism after invasion". Biology Letters 9, n.º 4 (23 de agosto de 2013): 20130342. http://dx.doi.org/10.1098/rsbl.2013.0342.

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Symbiont fidelity is an important mechanism in the evolution and stability of mutualisms. Strict fidelity has been assumed for the obligate mutualism between Sirex woodwasps and their mutualistic Amylostereum fungi. This assumption has been challenged in North America where the European woodwasp, Sirex noctilio , and its fungal mutualist, Amylostereum areolatum , have recently been introduced. We investigate the specificity of the mutualism between Sirex and Amylostereum species in Canada, where S. noctilio co-infests Pinus with native Sirex nigricornis and its mutualist, Amylostereum chailletii . Using phylogenetic and culture methods, we show that extensive, reciprocal exchange of fungal species and strains is occurring, with 75.3 per cent of S. nigricornis carrying A. areolatum and 3.5 per cent of S. noctilio carrying A. chailletii . These findings show that the apparent specificity of the mutualism between Sirex spp. and their associated Amylostereum spp. is not the result of specific biological mechanisms that maintain symbiont fidelity. Rather, partner switching may be common when shifting geographical distributions driven by ecological or anthropogenic forces bring host and mutualist pairs into sympatry. Such novel associations have potentially profound consequences for fitness and virulence. Symbiont sharing, if it occurs commonly, may represent an important but overlooked mechanism of community change linked to biological invasions.

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27

Münchhoff, Julia, Euichi Hirose, Tadashi Maruyama, Michio Sunairi, Brendan P. Burns y Brett A. Neilan. "Host specificity and phylogeography of the prochlorophyte Prochloron sp., an obligate symbiont in didemnid ascidians". Environmental Microbiology 9, n.º 4 (abril de 2007): 890–99. http://dx.doi.org/10.1111/j.1462-2920.2006.01209.x.

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28

Matthews, Jennifer L., Clinton A. Oakley, Adrian Lutz, Katie E. Hillyer, Ute Roessner, Arthur R. Grossman, Virginia M. Weis y Simon K. Davy. "Partner switching and metabolic flux in a model cnidarian–dinoflagellate symbiosis". Proceedings of the Royal Society B: Biological Sciences 285, n.º 1892 (28 de noviembre de 2018): 20182336. http://dx.doi.org/10.1098/rspb.2018.2336.

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Metabolite exchange is fundamental to the viability of the cnidarian–Symbiodiniaceae symbiosis and survival of coral reefs. Coral holobiont tolerance to environmental change might be achieved through changes in Symbiodiniaceae species composition, but differences in the metabolites supplied by different Symbiodiniaceae species could influence holobiont fitness. Using 13 C stable-isotope labelling coupled to gas chromatography–mass spectrometry, we characterized newly fixed carbon fate in the model cnidarian Exaiptasia pallida (Aiptasia) when experimentally colonized with either native Breviolum minutum or non-native Durusdinium trenchii . Relative to anemones containing B. minutum , D. trenchii -colonized hosts exhibited a 4.5-fold reduction in 13 C-labelled glucose and reduced abundance and diversity of 13 C-labelled carbohydrates and lipogenesis precursors, indicating symbiont species-specific modifications to carbohydrate availability and lipid storage. Mapping carbon fate also revealed significant alterations to host molecular signalling pathways. In particular, D. trenchii- colonized hosts exhibited a 40-fold reduction in 13 C-labelled scyllo -inositol, a potential interpartner signalling molecule in symbiosis specificity. 13 C-labelling also highlighted differential antioxidant- and ammonium-producing pathway activities, suggesting physiological responses to different symbiont species. Such differences in symbiont metabolite contribution and host utilization may limit the proliferation of stress-driven symbioses; this contributes valuable information towards future scenarios that select in favour of less-competent symbionts in response to environmental change.

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29

Keshavmurthy, Shashank, Hwee Sze Tee, Kuo-Wei Kao, Jih-Terng Wang y Chaolun Allen Chen. "Specificity trumps flexibility—location-based stable associations between Symbiodiniaceae genera and Platygyra verweyi (Scleractinia; Merulinidae)". PeerJ 8 (5 de mayo de 2020): e8791. http://dx.doi.org/10.7717/peerj.8791.

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This study monitored symbiont communities bi-monthly in native coral cores used in a reciprocal transplantation of the coral Platygyra verweyi over two years (2014–2016) and samples of mother colonies from three locations with variable thermal regimes; our results show that associating with multiple Symbiodiniaceae genera (Cladocopium spp. and Durusdinium spp.) is not a prerequisite for symbiont shuffling. Platygyra verweyi associates with certain Symbiodiniaceae genera based on location. Results of quantitative real-time PCR indicated small-scale temporal changes in Symbiodiniaceae genera compositions from 2014 to 2016; however, these changes were not enough to invoke shuffling or switching, despite degree heating weeks exceeding 6 °C-weeks in 2014 and 4 °C-weeks in 2015, which usually resulted in substantial coral bleaching. Microsatellite analysis of the P. verweyi host showed no genetic differences among the study locations. Our results suggest that P. verweyi undergoes long-term acclimatization and/or adaptation based on microgeographic and local environmental conditionsby altering its combinations of associated Symbiodiniaceae. Results also suggest that shuffling might not be as common a phenomenon as it has been given credit for; corals thrive through specific associations, and many corals could still be vulnerable to climate change-induced stress, despite being promiscuous or able to associate with rare and background Symbiodiniaceae genera.

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30

Anollés, Gustavo Caetano y Gabriel Favelukes. "Host-Symbiont Specificity Expressed during Early Adsorption of Rhizobium meliloti to the Root Surface of Alfalfa †". Applied and Environmental Microbiology 52, n.º 2 (1986): 377–82. http://dx.doi.org/10.1128/aem.52.2.377-382.1986.

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31

Osman, Eslam O. y Alexis M. Weinnig. "Microbiomes and Obligate Symbiosis of Deep-Sea Animals". Annual Review of Animal Biosciences 10, n.º 1 (15 de febrero de 2022): 151–76. http://dx.doi.org/10.1146/annurev-animal-081621-112021.

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Microbial communities associated with deep-sea animals are critical to the establishment of novel biological communities in unusual environments. Over the past few decades, rapid exploration of the deep sea has enabled the discovery of novel microbial communities, some of which form symbiotic relationships with animal hosts. Symbiosis in the deep sea changes host physiology, behavior, ecology, and evolution over time and space. Symbiont diversity within a host is often aligned with diverse metabolic pathways that broaden the environmental niche for the animal host. In this review, we focus on microbiomes and obligate symbionts found in different deep-sea habitats and how they facilitate survival of the organisms that live in these environments. In addition, we discuss factors that govern microbiome diversity, host specificity, and biogeography in the deep sea. Finally, we highlight the current limitations of microbiome research and draw a road map for future directions to advance our knowledge of microbiomes in the deep sea.

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32

Tsang, Ling Ming, Ka Hou Chu, Yoko Nozawa y Benny Kwok Kan Chan. "Morphological and host specificity evolution in coral symbiont barnacles (Balanomorpha: Pyrgomatidae) inferred from a multi-locus phylogeny". Molecular Phylogenetics and Evolution 77 (agosto de 2014): 11–22. http://dx.doi.org/10.1016/j.ympev.2014.03.002.

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33

van de Peppel, Lennart J. J. y Duur K. Aanen. "High diversity and low host-specificity of Termitomyces symbionts cultivated by Microtermes spp. indicate frequent symbiont exchange". Fungal Ecology 45 (junio de 2020): 100917. http://dx.doi.org/10.1016/j.funeco.2020.100917.

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34

Cooke, Ira, Hua Ying, Sylvain Forêt, Pim Bongaerts, Jan M. Strugnell, Oleg Simakov, Jia Zhang et al. "Genomic signatures in the coral holobiont reveal host adaptations driven by Holocene climate change and reef specific symbionts". Science Advances 6, n.º 48 (noviembre de 2020): eabc6318. http://dx.doi.org/10.1126/sciadv.abc6318.

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Genetic signatures caused by demographic and adaptive processes during past climatic shifts can inform predictions of species’ responses to anthropogenic climate change. To identify these signatures in Acropora tenuis, a reef-building coral threatened by global warming, we first assembled the genome from long reads and then used shallow whole-genome resequencing of 150 colonies from the central inshore Great Barrier Reef to inform population genomic analyses. We identify population structure in the host that reflects a Pleistocene split, whereas photosymbiont differences between reefs most likely reflect contemporary (Holocene) conditions. Signatures of selection in the host were associated with genes linked to diverse processes including osmotic regulation, skeletal development, and the establishment and maintenance of symbiosis. Our results suggest that adaptation to post-glacial climate change in A. tenuis has involved selection on many genes, while differences in symbiont specificity between reefs appear to be unrelated to host population structure.

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35

Onchuru, Thomas Ogao, Edward Edmond Makhulu, Purity Cassandra Ronnie, Stancy Mandere, Fidel Gabriel Otieno, Joseph Gichuhi y Jeremy Keith Herren. "The Plasmodium transmission-blocking symbiont, Microsporidia MB, is vertically transmitted through Anopheles arabiensis germline stem cells". PLOS Pathogens 20, n.º 11 (11 de noviembre de 2024): e1012340. http://dx.doi.org/10.1371/journal.ppat.1012340.

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Microsporidia MB is a promising candidate for developing a symbiont-based strategy for malaria control because it disrupts the capacity of An. arabiensis to transmit the Plasmodium parasite. The symbiont is predominantly localized in the reproductive organs and is transmitted vertically from mother to offspring and horizontally (sexually) during mating. Due to the contribution of both transmission routes, Microsporidia MB has the potential to spread through target vector populations and become established at high prevalence. Stable and efficient vertical transmission of Microsporidia MB is important for its sustainable use for malaria control, however, the vertical transmission efficiency of Microsporidia MB can vary. In this study, we investigate the mechanistic basis of Microsporidia MB vertical transmission in An. arabiensis. We show that vertical transmission occurs through the acquisition of Microsporidia MB by Anopheles cystocyte progenitors following the division of germline stem cells. We also show that Microsporidia MB replicates to increase infection intensity in the oocyte of developing eggs when mosquitoes take a blood meal suggesting that symbiont proliferation in the ovary is coordinated with egg development. The rate of Microsporidia MB transmission to developing eggs is on average higher than the recorded (mother to adult offspring) vertical transmission rate. This likely indicates that a significant proportion of An. arabiensis offspring lose their Microsporidia MB symbionts during development. The stability of germline stem cell infections, coordination of symbiont proliferation, and very high rate of transmission from germline stem cells to developing eggs indicate that Microsporidia MB has a highly specialized vertical transmission strategy in An. arabiensis, which may explain host specificity.

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36

Godbout, C. y J. A. Fortin. "Synthesized ectomycorrhizae of aspen: fungal genus level of structural characterization". Canadian Journal of Botany 63, n.º 2 (1 de febrero de 1985): 252–62. http://dx.doi.org/10.1139/b85-029.

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The ability of Populus tremuloides Michx. to form ectomycorrhizae with identified species of fungi was investigated using a pouch technique. Twenty-nine out of 54 fungus species formed ectomycorrhizae on aspen seedlings. Aspen seems to display little specificity for ectomycorrhizal fungi. Only epidermal Hartig nets were observed in the synthesized ectomycorrhizae and periepidermal ones were frequently encountered. Structural and morphological characteristics of ectomycorrhizae are presented by genus of mycorrhizal fungi. This grouping of characters by genus seems possible independently of the host plant. The classification of ectomycorrhizae is viewed in a new way in which structural types would be taxonomically related to the genus of the fungal symbiont.

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37

Kim Tiam, Sandra, Hasna Boubakri, Lorine Bethencourt, Danis Abrouk, Pascale Fournier y Aude Herrera-Belaroussi. "Genomic Insights of Alnus-Infective Frankia Strains Reveal Unique Genetic Features and New Evidence on Their Host-Restricted Lifestyle". Genes 14, n.º 2 (20 de febrero de 2023): 530. http://dx.doi.org/10.3390/genes14020530.

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The present study aimed to use comparative genomics to explore the relationships between Frankia and actinorhizal plants using a data set made of 33 Frankia genomes. The determinants of host specificity were first explored for “Alnus-infective strains” (i.e., Frankia strains belonging to Cluster Ia). Several genes were specifically found in these strains, including an agmatine deiminase which could possibly be involved in various functions as access to nitrogen sources, nodule organogenesis or plant defense. Within “Alnus-infective strains”, Sp+ Frankia genomes were compared to Sp− genomes in order to elucidate the narrower host specificity of Sp+ strains (i.e., Sp+ strains being capable of in planta sporulation, unlike Sp− strains). A total of 88 protein families were lost in the Sp+ genomes. The lost genes were related to saprophytic life (transcriptional factors, transmembrane and secreted proteins), reinforcing the proposed status of Sp+ as obligatory symbiont. The Sp+ genomes were also characterized by a loss of genetic and functional paralogs, highlighting a reduction in functional redundancy (e.g., hup genes) or a possible loss of function related to a saprophytic lifestyle (e.g., genes involved in gas vesicle formation or recycling of nutrients).

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38

Beliavskaia, Alexandra Y., Alexander V. Predeus, Sofya K. Garushyants, Maria D. Logacheva, Jun Gong, Songbao Zou, Mikhail S. Gelfand y Maria S. Rautian. "New Intranuclear Symbiotic Bacteria from Macronucleus of Paramecium putrinum—“Candidatus Gortzia Yakutica”". Diversity 12, n.º 5 (15 de mayo de 2020): 198. http://dx.doi.org/10.3390/d12050198.

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Holospora-like bacteria (HLB) are obligate intracellular Alphaproteobacteria, inhabiting nuclei of Paramecium and other ciliates such as “Candidatus Hafkinia” is in Frontonia. The HLB clade is comprised of four genera, Holospora, Preeria, “Candidatus Gortzia”, and “Candidatus Hafkinia”. These bacteria have a peculiar life cycle with two morphological forms and some degree of specificity to the host species and the type of nucleus they inhabit. Here we describe a novel species of HLB—“Candidatus Gortzia yakutica” sp. nov.—a symbiont from the macronucleus of Paramecium putrinum, the first described HLB for this Paramecium species. The new endosymbiont shows morphological similarities with other HLB. The phylogenetic analysis of the SSU rRNA gene places it into the “Candidatus Gortzia” clade.

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39

Fujishima, M. y M. Fujita. "Infection and maintenance of Holospora obtusa, a macronucleus-specific bacterium of the ciliate Paramecium caudatum". Journal of Cell Science 76, n.º 1 (1 de junio de 1985): 179–87. http://dx.doi.org/10.1242/jcs.76.1.179.

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The gram-negative bacterium Holospora obtusa is a macronucleus-specific symbiont of the ciliate Paramecium caudatum, which invades the host cell via a food vacuole, infects its macronucleus and grows exclusively in the nucleus. From infection experiments, we showed that a property of the macronucleus that is necessary for it to be recognized and infected by H. obtusa is commonly provided by P. caudatum, P. multimicronucleatum and 14 species of the P. aurelia complex, but not by P. jenningsi, P. bursaria, P. trichium, P. duboscqui, Didinium nasutum, Blepharisma japonicum, Pseudourostyla levis, seven species of Euplotes or Tetrahymena thermophila. Furthermore, it was also shown that the bacteria that infect the macronuclei of P. multimicronucleatum and the P. aurelia species complex always disappear from the nuclei within 5 days and the infected bacteria are maintained stably in the host nuclei in only 13 out of 22 strains of P. caudatum. The results indicate that the species specificity of the habitat of H. obtusa is not simply a matter of its ability to penetrate the host nuclear membrane but depends on unknown factors that exist only in certain strains of P. caudatum.

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40

Hamilton, Phineas T., Fangni Peng, Martin J. Boulanger y Steve J. Perlman. "A ribosome-inactivating protein in a Drosophila defensive symbiont". Proceedings of the National Academy of Sciences 113, n.º 2 (28 de diciembre de 2015): 350–55. http://dx.doi.org/10.1073/pnas.1518648113.

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Vertically transmitted symbionts that protect their hosts against parasites and pathogens are well known from insects, yet the underlying mechanisms of symbiont-mediated defense are largely unclear. A striking example of an ecologically important defensive symbiosis involves the woodland fly Drosophila neotestacea, which is protected by the bacterial endosymbiont Spiroplasma when parasitized by the nematode Howardula aoronymphium. The benefit of this defense strategy has led to the rapid spread of Spiroplasma throughout the range of D. neotestacea, although the molecular basis for this protection has been unresolved. Here, we show that Spiroplasma encodes a ribosome-inactivating protein (RIP) related to Shiga-like toxins from enterohemorrhagic Escherichia coli and that Howardula ribosomal RNA (rRNA) is depurinated during Spiroplasma-mediated protection of D. neotestacea. First, we show that recombinant Spiroplasma RIP catalyzes depurination of 28S rRNAs in a cell-free assay, as well as Howardula rRNA in vitro at the canonical RIP target site within the α-sarcin/ricin loop (SRL) of 28S rRNA. We then show that Howardula parasites in Spiroplasma-infected flies show a strong signal of rRNA depurination consistent with RIP-dependent modification and large decreases in the proportion of 28S rRNA intact at the α-sarcin/ricin loop. Notably, host 28S rRNA is largely unaffected, suggesting targeted specificity. Collectively, our study identifies a novel RIP in an insect defensive symbiont and suggests an underlying RIP-dependent mechanism in Spiroplasma-mediated defense.

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41

Popovici, Jean, Gilles Comte, Ã¯Â¿Â½milie Bagnarol, Nicole Alloisio, Pascale Fournier, Floriant Bellvert, CÃ¯Â¿Â½dric Bertrand y Maria P. Fernandez. "Differential Effects of Rare Specific Flavonoids on Compatible and Incompatible Strains in the Myrica gale-Frankia Actinorhizal Symbiosis". Applied and Environmental Microbiology 76, n.º 8 (26 de febrero de 2010): 2451–60. http://dx.doi.org/10.1128/aem.02667-09.

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ABSTRACT Plant secondary metabolites, and specifically phenolics, play important roles when plants interact with their environment and can act as weapons or positive signals during biotic interactions. One such interaction, the establishment of mutualistic nitrogen-fixing symbioses, typically involves phenolic-based recognition mechanisms between host plants and bacterial symbionts during the early stages of interaction. While these mechanisms are well studied in the rhizobia-legume symbiosis, little is known about the role of plant phenolics in the symbiosis between actinorhizal plants and Frankia genus strains. In this study, the responsiveness of Frankia strains to plant phenolics was correlated with their symbiotic compatibility. We used Myrica gale, a host species with narrow symbiont specificity, and a set of compatible and noncompatible Frankia strains. M. gale fruit exudate phenolics were extracted, and 8 dominant molecules were purified and identified as flavonoids by high-resolution spectroscopic techniques. Total fruit exudates, along with two purified dihydrochalcone molecules, induced modifications of bacterial growth and nitrogen fixation according to the symbiotic specificity of strains, enhancing compatible strains and inhibiting incompatible ones. Candidate genes involved in these effects were identified by a global transcriptomic approach using ACN14a strain whole-genome microarrays. Fruit exudates induced differential expression of 22 genes involved mostly in oxidative stress response and drug resistance, along with the overexpression of a whiB transcriptional regulator. This work provides evidence for the involvement of plant secondary metabolites in determining symbiotic specificity and expands our understanding of the mechanisms, leading to the establishment of actinorhizal symbioses.

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42

Weis, Virginia, Wendy Reynolds, Melissa deBoer y Dave Krupp. "Host-symbiont specificity during onset of symbiosis between the dinoflagellates Symbiodinium spp. and planula larvae of the scleractinian coral Fungia scutaria". Coral Reefs 20, n.º 3 (1 de noviembre de 2001): 301–8. http://dx.doi.org/10.1007/s003380100179.

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43

Swain, Timothy D., Mark W. Westneat, Vadim Backman y Luisa A. Marcelino. "Phylogenetic analysis of symbiont transmission mechanisms reveal evolutionary patterns in thermotolerance and host specificity that enhance bleaching resistance among vertically transmitted Symbiodinium". European Journal of Phycology 53, n.º 4 (26 de julio de 2018): 443–59. http://dx.doi.org/10.1080/09670262.2018.1466200.

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44

Pipes, Brian L. y Michele K. Nishiguchi. "Nocturnal Acidification: A Coordinating Cue in the Euprymna scolopes–Vibrio fischeri Symbiosis". International Journal of Molecular Sciences 23, n.º 7 (29 de marzo de 2022): 3743. http://dx.doi.org/10.3390/ijms23073743.

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The Vibrio fischeri–Euprymna scolopes symbiosis has become a powerful model for the study of specificity, initiation, and maintenance between beneficial bacteria and their eukaryotic partner. In this invertebrate model system, the bacterial symbionts are acquired every generation from the surrounding seawater by newly hatched squid. These symbionts colonize a specialized internal structure called the light organ, which they inhabit for the remainder of the host’s lifetime. The V. fischeri population grows and ebbs following a diel cycle, with high cell densities at night producing bioluminescence that helps the host avoid predation during its nocturnal activities. Rhythmic timing of the growth of the symbionts and their production of bioluminescence only at night is critical for maintaining the symbiosis. V. fischeri symbionts detect their population densities through a behavior termed quorum-sensing, where they secrete and detect concentrations of autoinducer molecules at high cell density when nocturnal production of bioluminescence begins. In this review, we discuss events that lead up to the nocturnal acidification of the light organ and the cues used for pre-adaptive behaviors that both host and symbiont have evolved. This host–bacterium cross talk is used to coordinate networks of regulatory signals (such as quorum-sensing and bioluminescence) that eventually provide a unique yet stable environment for V. fischeri to thrive and be maintained throughout its life history as a successful partner in this dynamic symbiosis.

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45

Bailly, Xavier, Isabelle Olivieri, Brigitte Brunel, Jean-Claude Cleyet-Marel y Gilles Béna. "Horizontal Gene Transfer and Homologous Recombination Drive the Evolution of the Nitrogen-Fixing Symbionts of Medicago Species". Journal of Bacteriology 189, n.º 14 (11 de mayo de 2007): 5223–36. http://dx.doi.org/10.1128/jb.00105-07.

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ABSTRACT Using nitrogen-fixing Sinorhizobium species that interact with Medicago plants as a model system, we aimed at clarifying how sex has shaped the diversity of bacteria associated with the genus Medicago on the interspecific and intraspecific scales. To gain insights into the diversification of these symbionts, we inferred a topology that includes the different specificity groups which interact with Medicago species, based on sequences of the nodulation gene cluster. Furthermore, 126 bacterial isolates were obtained from two soil samples, using Medicago truncatula and Medicago laciniata as host plants, to study the differentiation between populations of Sinorhizobium medicae, Sinorhizobium meliloti bv. meliloti, and S. meliloti bv. medicaginis. The former two can be associated with M. truncatula (among other species of Medicago), whereas the last organism is the specific symbiont of M. laciniata. These bacteria were characterized using a multilocus sequence analysis of four loci, located on the chromosome and on the two megaplasmids of S. meliloti. The phylogenetic results reveal that several interspecific horizontal gene transfers occurred during the diversification of Medicago symbionts. Within S. meliloti, the analyses show that nod genes specific to different host plants have spread to different genetic backgrounds through homologous recombination, preventing further divergence of the different ecotypes. Thus, specialization to different host plant species does not prevent the occurrence of gene flow among host-specific biovars of S. meliloti, whereas reproductive isolation between S. meliloti bv. meliloti and S. medicae is maintained even though these bacteria can cooccur in sympatry on the same individual host plants.

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Schechter, Shannon P. y Thomas D. Bruns. "A Common Garden Test of Host-Symbiont Specificity Supports a Dominant Role for Soil Type in Determining AMF Assemblage Structure in Collinsia sparsiflora". PLoS ONE 8, n.º 2 (5 de febrero de 2013): e55507. http://dx.doi.org/10.1371/journal.pone.0055507.

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47

Schmitt, Susanne, Hilde Angermeier, Roswitha Schiller, Niels Lindquist y Ute Hentschel. "Molecular Microbial Diversity Survey of Sponge Reproductive Stages and Mechanistic Insights into Vertical Transmission of Microbial Symbionts". Applied and Environmental Microbiology 74, n.º 24 (26 de septiembre de 2008): 7694–708. http://dx.doi.org/10.1128/aem.00878-08.

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ABSTRACT Many marine sponges, hereafter termed high-microbial-abundance (HMA) sponges, harbor large and complex microbial consortia, including bacteria and archaea, within their mesohyl matrices. To investigate vertical microbial transmission as a strategy to maintain these complex associations, an extensive phylogenetic analysis was carried out with the 16S rRNA gene sequences of reproductive (n = 136) and adult (n = 88) material from five different Caribbean species, as well as all published 16S rRNA gene sequences from sponge offspring (n = 116). The overall microbial diversity, including members of at least 13 bacterial phyla and one archaeal phylum, in sponge reproductive stages is high. In total, 28 vertical-transmission clusters, defined as clusters of phylotypes that are found both in adult sponges and their offspring, were identified. They are distributed among at least 10 bacterial phyla and one archaeal phylum, demonstrating that the complex adult microbial community is collectively transmitted through reproductive stages. Indications of host-species specificity and cospeciation were not observed. Mechanistic insights were provided using a combined electron microscopy and fluorescence in situ hybridization analysis, and an indirect mechanism of vertical transmission via nurse cells is proposed for the oviparous sponge Ectyoplasia ferox. Based on these phylogenetic and mechanistic results, we suggest the following symbiont transmission model: entire microbial consortia are vertically transmitted in sponges. While vertical transmission is clearly present, additional environmental transfer between adult individuals of the same and even different species might obscure possible signals of cospeciation. We propose that associations of HMA sponges with highly sponge-specific microbial communities are maintained by this combination of vertical and horizontal symbiont transmission.

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LaJeunesse, Todd C., Daniel T. Pettay, Eugenia M. Sampayo, Niphon Phongsuwan, Barbara Brown, David O. Obura, Ove Hoegh-Guldberg y William K. Fitt. "Long-standing environmental conditions, geographic isolation and host-symbiont specificity influence the relative ecological dominance and genetic diversification of coral endosymbionts in the genusSymbiodinium". Journal of Biogeography 37, n.º 5 (mayo de 2010): 785–800. http://dx.doi.org/10.1111/j.1365-2699.2010.02273.x.

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Calevo, Jacopo, Samuele Voyron, Enrico Ercole y Mariangela Girlanda. "Is the Distribution of Two Rare Orchis Sister Species Limited by Their Main Mycobiont?" Diversity 12, n.º 7 (30 de junio de 2020): 262. http://dx.doi.org/10.3390/d12070262.

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As orchids rely on their mycorrhizal fungi for nutrient supply, their spatial range is dependent on the distribution of orchid mycorrhizal (OM) fungi. We addressed possible correlations between mycorrhizal specificity and the geographic distribution of orchids and OM fungi in three populations of the rare sister species Orchis patens and O. canariensis. Metabarcoding of the fungal ITS2 region indicated that, although adult plants of either species were colonized by several ceratobasidioid, tulasnelloid, sebacinoid and serendipitoid fungi, the mycobiont spectra were dominated by Tulasnella helicospora (which occurred in 100% of examined plants with high read numbers), which is a globally distributed fungus. In vitro assays with a T. helicospora isolate obtained from O. patens indicated the effectiveness of this OM fungus at germinating seeds of its native host. At a local scale, higher read numbers for T. helicospora were found in soil samples collected underneath O. patens roots than at locations unoccupied by the orchid. Although these findings suggest that the geographical pattern of the main fungal symbiont does not limit the distribution of O. patens and O. canariensis at this scale, the actual causal link between orchid and OM fungal occurrence/abundance still needs to be better understood.

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Nyholm, Spencer V. y Margaret J. McFall-Ngai. "Dominance of Vibrio fischeri in Secreted Mucus outside the Light Organ of Euprymna scolopes: the First Site of Symbiont Specificity". Applied and Environmental Microbiology 69, n.º 7 (julio de 2003): 3932–37. http://dx.doi.org/10.1128/aem.69.7.3932-3937.2003.

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ABSTRACT Previous studies of the Euprymna scolopes-Vibrio fischeri symbiosis have demonstrated that, during colonization, the hatchling host secretes mucus in which gram-negative environmental bacteria amass in dense aggregations outside the sites of infection. In this study, experiments with green fluorescent protein-labeled symbiotic and nonsymbiotic species of gram-negative bacteria were used to characterize the behavior of cells in the aggregates. When hatchling animals were exposed to 103 to 106 V. fischeri cells/ml added to natural seawater, which contains a mix of approximately 106 nonspecific bacterial cells/ml, V. fischeri cells were the principal bacterial cells present in the aggregations. Furthermore, when animals were exposed to equal cell numbers of V. fischeri (either a motile or a nonmotile strain) and either Vibrio parahaemolyticus or Photobacterium leiognathi, phylogenetically related gram-negative bacteria that also occur in the host's habitat, the symbiont cells were dominant in the aggregations. The presence of V. fischeri did not compromise the viability of these other species in the aggregations, and no significant growth of V. fischeri cells was detected. These findings suggested that dominance results from the ability of V. fischeri either to accumulate or to be retained more effectively within the mucus. Viability of the V. fischeri cells was required for both the formation of tight aggregates and their dominance in the mucus. Neither of the V. fischeri quorum-sensing compounds accumulated in the aggregations, which suggested that the effects of these small signal molecules are not critical to V. fischeri dominance. Taken together, these data provide evidence that the specificity of the squid-vibrio symbiosis begins early in the interaction, in the mucus where the symbionts aggregate outside of the light organ.

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