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1
Tapanila, Leif. "Direct Evidence of Ancient Symbiosis Using Trace Fossils." Paleontological Society Papers 14 (October 2008): 271–87. http://dx.doi.org/10.1017/s1089332600001728.
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Symbiotic associations are a poorly studied aspect of the fossil record, owing largely to the taphonomic biases that inhibit direct observation that two organisms shared an intimate association in life. A symbiosis between an infesting animal and a skeleton-producing host can form a bioclaustration cavity that directly preserves the association and has a high preservation potential. Identification of ancient mutuals and parasites must reject the null hypothesis of commensalism by demonstrating that the symbiosis correlates with a positive or negative change in host fitness as compared to a non-symbiotic relative of the host taxon. Reviews of the Paleozoic record of marine symbionts show that the majority are hosted by colonial animals, especially corals and calcareous sponges. These hosts include structural forms that have moderate to high levels of integration and can support bioclaustrations between clonal units, mitigating the negative effects of symbionts, and perhaps facilitating the symbiosis.The fossil record is biased toward recording long-lasting, widespread, equilibrated associations. By contrast, parasitisms that are especially negative to the host are expected to be fossilized rarely. The symbiotic associations that form bioclaustrations may also represent an endolithic adaptive strategy in response to biological antagonisms, such as predation and spatial competition. The Late Ordovician rise in symbiotic bioclaustrations joins burrows and borings as trace fossil examples of infaunalization strategies that accompany the Ordovician faunal radiation.
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Vader, Wim, and Anne Helene S. Tandberg. "Amphipods and sea anemones, an update." Journal of Crustacean Biology 40, no. 6 (2020): 872–78. http://dx.doi.org/10.1093/jcbiol/ruaa061.
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Abstract We present an updated survey of the Amphipoda that live in association with sea anemones. These amphipods can be divided into four groups: 1) symbiotic amphipods using sea anemones mainly for protection, but feeding largely independently; 2) amphipods feeding on sea anemones, but not permanently associated; 3) symbiotic amphipods living permanently among the tentacles of the sea anemones; and 4) symbiotic amphipods living permanently in the gastrovascular cavity of the sea anemones. Contrary to previous speculations, it appears that the amphipods in groups 3 and 4 mainly feed on host tissue, and the anemone-eating amphipods can therefore generally be classified as micropredators (group 2), ectoparasites (group 3), and almost endoparasites (especially those species in group 4 that spend their entire life cycle inside their hosts). Although the associates in the latter two groups show various minor morphological, reproductive, and physiological adaptations to the symbiosis, these associations evolved many times independently. We provide new information on feeding ecology and a discussion of the evolution of these associations.
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Douglas, Angela E. "Housing microbial symbionts: evolutionary origins and diversification of symbiotic organs in animals." Philosophical Transactions of the Royal Society B: Biological Sciences 375, no. 1808 (2020): 20190603. http://dx.doi.org/10.1098/rstb.2019.0603.
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In many animal hosts, microbial symbionts are housed within specialized structures known as symbiotic organs, but the evolutionary origins of these structures have rarely been investigated. Here, I adopt an evolutionary developmental (evo-devo) approach, specifically to apply knowledge of the development of symbiotic organs to gain insights into their evolutionary origins and diversification. In particular, host genetic changes associated with evolution of symbiotic organs can be inferred from studies to identify the host genes that orchestrate the development of symbiotic organs, recognizing that microbial products may also play a key role in triggering the developmental programme in some associations. These studies may also reveal whether higher animal taxonomic groups (order, class, phylum, etc.) possess a common genetic regulatory network for symbiosis that is latent in taxa lacking symbiotic organs, and activated at the origination of symbiosis in different host lineages. In this way, apparent instances of convergent evolution of symbiotic organs may be homologous in terms of a common genetic blueprint for symbiosis. Advances in genetic technologies, including reverse genetic tools and genome editing, will facilitate the application of evo-devo approaches to investigate the evolution of symbiotic organs in animals. This article is part of the theme issue ‘The role of the microbiome in host evolution’.
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Zuo, Ya-Bo, Da-Yong Han, Yan-Yan Wang, et al. "Fungal–Algal Association Drives Lichens’ Mutualistic Symbiosis: A Case Study with Trebouxia-Related Lichens." Plants 12, no. 17 (2023): 3172. http://dx.doi.org/10.3390/plants12173172.
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Biotic and abiotic factors influence the formation of fungal–algal pairings in lichen symbiosis. However, the specific determinants of these associations, particularly when distantly related fungi are involved, remain poorly understood. In this study, we investigated the impact of different drivers on the association patterns between taxonomically diverse lichenized fungi and their trebouxioid symbiotic partners. We collected 200 samples from four biomes and identified 41 species of lichenized fungi, associating them with 16 species of trebouxioid green algae, of which 62% were previously unreported. The species identity of both the fungal and algal partners had the most significant effect on the outcome of the symbiosis, compared to abiotic factors like climatic variables and geographic distance. Some obviously specific associations were observed in the temperate zone; however, the nestedness value was lower in arid regions than in cold, polar, and temperate regions according to interaction network analysis. Cophylogenetic analyses revealed congruent phylogenies between trebouxioid algae and associated fungi, indicating a tendency to reject random associations. The main evolutionary mechanisms contributing to the observed phylogenetic patterns were “loss” and “failure to diverge” of the algal partners. This study broadens our knowledge of fungal–algal symbiotic patterns in view of Trebouxia-associated fungi.
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Delaux, Pierre-Marc. "Comparative phylogenomics of symbiotic associations." New Phytologist 213, no. 1 (2016): 89–94. http://dx.doi.org/10.1111/nph.14161.
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Acar, Tessa, Sandra Moreau, Marie-Françoise Jardinaud, et al. "The association between Dioscorea sansibarensis and Orrella dioscoreae as a model for hereditary leaf symbiosis." PLOS ONE 19, no. 4 (2024): e0302377. http://dx.doi.org/10.1371/journal.pone.0302377.
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Hereditary, or vertically-transmitted, symbioses affect a large number of animal species and some plants. The precise mechanisms underlying transmission of functions of these associations are often difficult to describe, due to the difficulty in separating the symbiotic partners. This is especially the case for plant-bacteria hereditary symbioses, which lack experimentally tractable model systems. Here, we demonstrate the potential of the leaf symbiosis between the wild yam Dioscorea sansibarensis and the bacterium Orrella dioscoreae (O. dioscoreae) as a model system for hereditary symbiosis. O. dioscoreae is easy to grow and genetically manipulate, which is unusual for hereditary symbionts. These properties allowed us to design an effective antimicrobial treatment to rid plants of bacteria and generate whole aposymbiotic plants, which can later be re-inoculated with bacterial cultures. Aposymbiotic plants did not differ morphologically from symbiotic plants and the leaf forerunner tip containing the symbiotic glands formed normally even in the absence of bacteria, but microscopic differences between symbiotic and aposymbiotic glands highlight the influence of bacteria on the development of trichomes and secretion of mucilage. This is to our knowledge the first leaf symbiosis where both host and symbiont can be grown separately and where the symbiont can be genetically altered and reintroduced to the host.
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Benabdoun, Faïza Meriem, Mathish Nambiar-Veetil, Leandro Imanishi, et al. "Composite Actinorhizal Plants with Transgenic Roots for the Study of Symbiotic Associations with Frankia." Journal of Botany 2011 (November 1, 2011): 1–8. http://dx.doi.org/10.1155/2011/702947.
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More than 200 species of dicotyledonous plants belonging to eight different families and 24 genera can establish actinorhizal symbiosis with the nitrogen-fixing soil actinomycete Frankia. Compared to the symbiotic interaction between legumes and rhizobia, little is known about the molecular basis of the infection process and nodule formation in actinorhizal plants. Here, we review a gene transfer system based on Agrobacterium rhizogenes that opens the possibility to rapidly analyze the function of candidate symbiotic genes. The transformation protocol generates “composite plants” that consist of a nontransgenic aerial part with transformed hairy roots. Composite plants have already been obtained in three different species of actinorhizal plants, including the tropical tree species Casuarina glauca, the Patagonian shrub Discaria trinervis, and the nonwoody plant Datisca glomerata. The potential of this technique to advancing our understanding of the molecular mechanisms underlying infection by Frankia is demonstrated by functional analyses of symbiotic genes.
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Read, D. J., J. G. Duckett, R. Francis, R. Ligrone, and A. Russell. "Symbiotic fungal associations in ‘lower’ land plants." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 355, no. 1398 (2000): 815–31. http://dx.doi.org/10.1098/rstb.2000.0617.
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An analysis of the current state of knowledge of symbiotic fungal associations in ‘lower’ plants is provided. Three fungal phyla, the Zygomycota, Ascomycota and Basidiomycota, are involved in forming these associations, each producing a distinctive suite of structural features in well–defined groups of ‘lower’ plants. Among the ‘lower’ plants only mosses and Equisetum appear to lack one or other of these types of association. The salient features of the symbioses produced by each fungal group are described and the relationships between these associations and those formed by the same or related fungi in ‘higher’ plants are discussed. Particular consideration is given to the question of the extent to which root–fungus associations in ‘lower’ plants are analogous to ‘mycorrhizas’ of ‘higher’ plants and the need for analysis of the functional attributes of these symbioses is stressed. Zygomycetous fungi colonize a wide range of extant lower land plants (hornworts, many hepatics, lycopods, Ophioglossales, Psilotales and Gleicheniaceae), where they often produce structures analogous to those seen in the vesicular–arbuscular (VA) mycorrhizas of higher plants, which are formed by members of the order Glomales. A preponderance of associations of this kind is in accordance with palaeobotanical and molecular evidence indicating that glomalean fungi produced the archetypal symbioses with the first plants to emerge on to land. It is shown, probably for the first time, that glomalean fungi forming typical VA mycorrhiza with a higher plant ( Plantago lanceolata ) can colonize a thalloid liverwort ( Pellia epiphylla ), producing arbuscules and vesicles in the hepatic. The extent to which these associations, which are structurally analogous to mycorrhizas, have similar functions remains to be evaluated. Ascomycetous associations are found in a relatively small number of families of leafy liverworts. The structural features of the fungal colonization of rhizoids and underground axes of these plants are similar to those seen in mycorrhizal associations of ericaceous plants like Vaccinium . Cross inoculation experiments have confirmed that a typical mycorrhizal endophyte of ericaceous plants, Hymenoscyphus ericae , will form associations in liverworts which are structurally identical to those seen in nature. Again, the functional significance of these associations remains to be examined. Some members of the Jungermanniales and Metzgeriales form associations with basidiomycetous fungi. These produce intracellular coils of hyphae, which are similar to the pelotons seen in orchid mycorrhizas, which also involve basidiomycetes. The fungal associates of the autotrophic Aneura and of its heterotrophic relative Cryptothallus mirabilis have been isolated. In the latter case it has been shown that the fungal symbiont is an ectomycorrhizal associate of Betula , suggesting that the apparently obligate nature of the association between the hepatic and Betula in nature is based upon requirement for this particular heterotroph.
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Baumann, P. "Symbiotic Associations Involving Microorganisms: A special issue devoted to some less well known symbiotic associations." BioScience 48, no. 4 (1998): 254–55. http://dx.doi.org/10.1093/bioscience/48.4.254.
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Dellagi, Alia, Isabelle Quillere, and Bertrand Hirel. "Beneficial soil-borne bacteria and fungi: a promising way to improve plant nitrogen acquisition." Journal of Experimental Botany 71, no. 15 (2020): 4469–79. http://dx.doi.org/10.1093/jxb/eraa112.
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Abstract Nitrogen (N) is an essential element for plant productivity, thus, it is abundantly applied to the soil in the form of organic or chemical fertilizers that have negative impacts on the environment. Exploiting the potential of beneficial microbes and identifying crop genotypes that can capitalize on symbiotic associations may be possible ways to significantly reduce the use of N fertilizers. The best-known example of symbiotic association that can reduce the use of N fertilizers is the N2-fixing rhizobial bacteria and legumes. Bacterial taxa other than rhizobial species can develop associative symbiotic interactions with plants and also fix N. These include bacteria of the genera Azospirillum, Azotobacter, and Bacillus, some of which are commercialized as bio-inoculants. Arbuscular mycorrhizal fungi are other microorganisms that can develop symbiotic associations with most terrestrial plants, favoring access to nutrients in a larger soil volume through their extraradical mycelium. Using combinations of different beneficial microbial species is a promising strategy to boost plant N acquisition and foster a synergistic beneficial effect between symbiotic microorganisms. Complex biological mechanisms including molecular, metabolic, and physiological processes dictate the establishment and efficiency of such multipartite symbiotic associations. In this review, we present an overview of the current knowledge and future prospects regarding plant N nutrition improvement through the use of beneficial bacteria and fungi associated with plants, individually or in combination.
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VINN, OLEV, MARK A. WILSON, ANNA MADISON, ELIZAVETA KAZANTSEVA, and URSULA TOOM. "FIRST SYMBIOTIC ASSOCIATION BETWEEN HEDERELLOIDS AND RUGOSE CORALS (LATEST SILURIAN OF SAAREMAA, ESTONIA)." PALAIOS 37, no. 7 (2022): 368–73. http://dx.doi.org/10.2110/palo.2022.005.
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ABSTRACT A phoronid-like hederelloid that formed a symbiotic association with the rugosan coral Entelophyllum has been found in the Pridoli Series of Estonia. The skeletons of the hederelloid and rugosan are partially intergrown. The hederelloid apertures are located at the margin of the rugosan calice. The hederelloid lophophore was likely placed between the tentacles of the coral polyp, indicating a positive or at least a neutral co-existence. In extant corals, polyps can be retracted into the calice either during the day or night. If the rugose coral was similar to modern corals in this respect, it may have helped in the co-existence with the hederelloid and allowed feeding at different times. It is possible that the hederelloid soft tissues were protected against smaller predators by the stinging cells of the rugosan tentacles. The history of symbiosis in hederelloids is similar to that of tentaculitoids, in which symbiotic relationships also appeared early in their evolution. To date, Entelophyllum is the only colonial rugosan known to have formed symbiotic associations during the Silurian.
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Little, Ainslie E. F., and Cameron R. Currie. "Symbiotic complexity: discovery of a fifth symbiont in the attine ant–microbe symbiosis." Biology Letters 3, no. 5 (2007): 501–4. http://dx.doi.org/10.1098/rsbl.2007.0253.
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The fungus-growing ant–microbe mutualism is a classic example of organismal complexity generated through symbiotic association. The ants have an ancient obligate mutualism with fungi they cultivate for food. The success of the mutualism is threatened by specialized fungal parasites ( Escovopsis ) that consume the cultivated fungus. To defend their nutrient-rich garden against infection, the ants have a second mutualism with bacteria ( Pseudonocardia ), which produce antibiotics that inhibit the garden parasite Escovopsis . Here we reveal the presence of a fourth microbial symbiont associated with fungus-growing ants: black yeasts (Ascomycota; Phialophora ). We show that black yeasts are commonly associated with fungus-growing ants, occurring throughout their geographical distribution. Black yeasts grow on the ants' cuticle, specifically localized to where the mutualistic bacteria are cultured. Molecular phylogenetic analyses reveal that the black yeasts form a derived monophyletic lineage associated with the phylogenetic diversity of fungus growers. The prevalence, distribution, localization and monophyly indicate that the black yeast is a fifth symbiont within the attine ant–microbe association, further exemplifying the complexity of symbiotic associations.
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Delaux, Pierre-Marc, and Sebastian Schornack. "Plant evolution driven by interactions with symbiotic and pathogenic microbes." Science 371, no. 6531 (2021): eaba6605. http://dx.doi.org/10.1126/science.aba6605.
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During 450 million years of diversification on land, plants and microbes have evolved together. This is reflected in today’s continuum of associations, ranging from parasitism to mutualism. Through phylogenetics, cell biology, and reverse genetics extending beyond flowering plants into bryophytes, scientists have started to unravel the genetic basis and evolutionary trajectories of plant-microbe associations. Protection against pathogens and support of beneficial, symbiotic, microorganisms are sustained by a blend of conserved and clade-specific plant mechanisms evolving at different speeds. We propose that symbiosis consistently emerges from the co-option of protection mechanisms and general cell biology principles. Exploring and harnessing the diversity of molecular mechanisms used in nonflowering plant-microbe interactions may extend the possibilities for engineering symbiosis-competent and pathogen-resilient crops.
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Jiménez-Guerrero, Irene, Carlos Medina, José María Vinardell, Francisco Javier Ollero, and Francisco Javier López-Baena. "The Rhizobial Type 3 Secretion System: The Dr. Jekyll and Mr. Hyde in the Rhizobium–Legume Symbiosis." International Journal of Molecular Sciences 23, no. 19 (2022): 11089. http://dx.doi.org/10.3390/ijms231911089.
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Rhizobia are soil bacteria that can establish a symbiotic association with legumes. As a result, plant nodules are formed on the roots of the host plants where rhizobia differentiate to bacteroids capable of fixing atmospheric nitrogen into ammonia. This ammonia is transferred to the plant in exchange of a carbon source and an appropriate environment for bacterial survival. This process is subjected to a tight regulation with several checkpoints to allow the progression of the infection or its restriction. The type 3 secretion system (T3SS) is a secretory system that injects proteins, called effectors (T3E), directly into the cytoplasm of the host cell, altering host pathways or suppressing host defense responses. This secretion system is not present in all rhizobia but its role in symbiosis is crucial for some symbiotic associations, showing two possible faces as Dr. Jekyll and Mr. Hyde: it can be completely necessary for the formation of nodules, or it can block nodulation in different legume species/cultivars. In this review, we compile all the information currently available about the effects of different rhizobial effectors on plant symbiotic phenotypes. These phenotypes are diverse and highlight the importance of the T3SS in certain rhizobium–legume symbioses.
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Gasca, Rebeca, Rebecca Hoover, and Steven H. D. Haddock. "New symbiotic associations of hyperiid amphipods (Peracarida) with gelatinous zooplankton in deep waters off California." Journal of the Marine Biological Association of the United Kingdom 95, no. 3 (2014): 503–11. http://dx.doi.org/10.1017/s0025315414001416.
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Hyperiid amphipods are holoplanktonic marine crustaceans that are known as temporary symbionts of different groups of gelatinous zooplankton. The nature and dynamics of these associations are still poorly understood, particularly in deep waters. The mesopelagic and deep-living planktonic fauna off Monterey Bay, California (down to 4000 m) was surveyed using a remotely operated submersible (ROV) and blue-water diving (BWD) between September 2005 and January 2008. In this work we report our observations on a total of 51 symbiotic associations observedin situ(not from zooplankton samples), between hyperiid amphipods and various taxa of gelatinous zooplankton. We present the first information on the symbiotic relations of the hyperiidVibilia caeca, and we provide data of 34 previously unknown symbiotic associations. The host range was expanded for several widely distributed hyperiid species. These findings suggest that the symbiotic associations between hyperiid amphipods and gelatinous zooplankton in deep waters deserve further study worldwide.
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Lushchenko, G. V., and V. I. Gasiev. "Symbiotic activity of nodule bacteria in alfalfa crops." BIO Web of Conferences 145 (2024): 02015. http://dx.doi.org/10.1051/bioconf/202414502015.
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A model association of legume-rhizobial symbiosis was obtained on a stamped callus culture of alfalfa roots when infected with Rhizobium meliloti. Using a culture aligned with the growth rate of strains, it was possible to obtain a reliable experimental model for studying the relationships of a legume plant with nodule bacteria. A regime has been worked out to obtain an effective imitation association of strain culture of callus tissues – fast-growing nodule bacteria on the example of infected with Rhizobium meliloti cells of callus tissues of alfalfa roots (Medicago sativa). The growth characteristics of the strain culture of the callus tissues of alfalfa roots were obtained: the most favorable period of infection of calluses with nodule bacteria was revealed; the optimal infectious load of nodule bacteria was selected – 5-7 rhizobia cells per 1 cell of alfalfa root callus; it was confirmed that incubation of associations on a medium containing a small amount of nitrogen and without kinetin contributes to the best manifestation of nitrogenase activity of associations. The act of introducing nodule bacteria of alfalfa into the cells of the tissue culture of its roots has been established. Bacteria were detected inside plant cells on the 7th day of infection of host plant tissues. The nitrogenase activity of the model systems increased with an increase in the incubation time of associations (from 1 to 4 days) on a medium without growth stimulants containing a small amount of nitrogen.
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Ntana, Fani, Sean R. Johnson, Björn Hamberger, Birgit Jensen, Hans J. L. Jørgensen, and David B. Collinge. "Regulation of Tomato Specialised Metabolism after Establishment of Symbiosis with the Endophytic Fungus Serendipita indica." Microorganisms 10, no. 1 (2022): 194. http://dx.doi.org/10.3390/microorganisms10010194.
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Specialised metabolites produced during plant-fungal associations often define how symbiosis between the plant and the fungus proceeds. They also play a role in the establishment of additional interactions between the symbionts and other organisms present in the niche. However, specialised metabolism and its products are sometimes overlooked when studying plant-microbe interactions. This limits our understanding of the specific symbiotic associations and potentially future perspectives of their application in agriculture. In this study, we used the interaction between the root endophyte Serendipita indica and tomato (Solanum lycopersicum) plants to explore how specialised metabolism of the host plant is regulated upon a mutualistic symbiotic association. To do so, tomato seedlings were inoculated with S. indica chlamydospores and subjected to RNAseq analysis. Gene expression of the main tomato specialised metabolism pathways was compared between roots and leaves of endophyte-colonised plants and tissues of endophyte-free plants. S. indica colonisation resulted in a strong transcriptional response in the leaves of colonised plants. Furthermore, the presence of the fungus in plant roots appears to induce expression of genes involved in the biosynthesis of lignin-derived compounds, polyacetylenes, and specific terpenes in both roots and leaves, whereas pathways producing glycoalkaloids and flavonoids were expressed in lower or basal levels.
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Donnelly, Aidan R., Elizabeth J. Giacobe, Rachel A. Cook, et al. "Quantification of the capacity of vibrio fischeri to establish symbiosis with Euprymna scolopes." PLOS ONE 18, no. 7 (2023): e0287519. http://dx.doi.org/10.1371/journal.pone.0287519.
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Most animals establish long-term symbiotic associations with bacteria that are critical for normal host physiology. The symbiosis that forms between the Hawaiian squid Euprymna scolopes and the bioluminescent bacterium Vibrio fischeri serves as an important model system for investigating the molecular mechanisms that promote animal-bacterial symbioses. E. scolopes hatch from their eggs uncolonized, which has led to the development of squid-colonization assays that are based on introducing culture-grown V. fischeri cells to freshly hatched juvenile squid. Recent studies have revealed that strains often exhibit large differences in how they establish symbiosis. Therefore, we sought to develop a simplified and reproducible protocol that permits researchers to determine appropriate inoculum levels and provides a platform to standardize the assay across different laboratories. In our protocol, we adapt a method commonly used for evaluating the infectivity of pathogens to quantify the symbiotic capacity of V. fischeri strains. The resulting metric, the symbiotic dose-50 (SD50), estimates the inoculum level that is necessary for a specific V. fischeri strain to establish a light-emitting symbiosis. Relative to other protocols, our method requires 2–5-fold fewer animals. Furthermore, the power analysis presented here suggests that the protocol can detect up to a 3-fold change in the SD50 between different strains.
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Simonsen, Anna K., and John R. Stinchcombe. "Standing genetic variation in host preference for mutualist microbial symbionts." Proceedings of the Royal Society B: Biological Sciences 281, no. 1797 (2014): 20142036. http://dx.doi.org/10.1098/rspb.2014.2036.
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Many models of mutualisms show that mutualisms are unstable if hosts lack mechanisms enabling preferential associations with mutualistic symbiotic partners over exploitative partners. Despite the theoretical importance of mutualism-stabilizing mechanisms, we have little empirical evidence to infer their evolutionary dynamics in response to exploitation by non-beneficial partners. Using a model mutualism—the interaction between legumes and nitrogen-fixing soil symbionts—we tested for quantitative genetic variation in plant responses to mutualistic and exploitative symbiotic rhizobia in controlled greenhouse conditions. We found significant broad-sense heritability in a legume host's preferential association with mutualistic over exploitative symbionts and selection to reduce frequency of associations with exploitative partners. We failed to detect evidence that selection will favour the loss of mutualism-stabilizing mechanisms in the absence of exploitation, as we found no evidence for a fitness cost to the host trait or indirect selection on genetically correlated traits. Our results show that genetic variation in the ability to preferentially reduce associations with an exploitative partner exists within mutualisms and is under selection, indicating that micro-evolutionary responses in mutualism-stabilizing traits in the face of rapidly evolving mutualistic and exploitative symbiotic bacteria can occur in natural host populations.
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Delaux, Pierre-Marc, Guru V. Radhakrishnan, Dhileepkumar Jayaraman, et al. "Algal ancestor of land plants was preadapted for symbiosis." Proceedings of the National Academy of Sciences 112, no. 43 (2015): 13390–95. http://dx.doi.org/10.1073/pnas.1515426112.
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Colonization of land by plants was a major transition on Earth, but the developmental and genetic innovations required for this transition remain unknown. Physiological studies and the fossil record strongly suggest that the ability of the first land plants to form symbiotic associations with beneficial fungi was one of these critical innovations. In angiosperms, genes required for the perception and transduction of diffusible fungal signals for root colonization and for nutrient exchange have been characterized. However, the origin of these genes and their potential correlation with land colonization remain elusive. A comprehensive phylogenetic analysis of 259 transcriptomes and 10 green algal and basal land plant genomes, coupled with the characterization of the evolutionary path leading to the appearance of a key regulator, a calcium- and calmodulin-dependent protein kinase, showed that the symbiotic signaling pathway predated the first land plants. In contrast, downstream genes required for root colonization and their specific expression pattern probably appeared subsequent to the colonization of land. We conclude that the most recent common ancestor of extant land plants and green algae was preadapted for symbiotic associations. Subsequent improvement of this precursor stage in early land plants through rounds of gene duplication led to the acquisition of additional pathways and the ability to form a fully functional arbuscular mycorrhizal symbiosis.
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Wang, Lidan, Shenglu Zhang, Jinjin Fang, Xinjie Jin, Reyim Mamut, and Pan Li. "The Chloroplast Genome of the Lichen Photobiont Trebouxiophyceae sp. DW1 and Its Phylogenetic Implications." Genes 13, no. 10 (2022): 1840. http://dx.doi.org/10.3390/genes13101840.
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Lichens are symbiotic associations of algae and fungi. The genetic mechanism of the symbiosis of lichens and the influence of symbiosis on the size and composition of the genomes of symbiotic algae have always been intriguing scientific questions explored by lichenologists. However, there were limited data on lichen genomes. Therefore, we isolated and purified a lichen symbiotic alga to obtain a single strain (Trebouxiophyceae sp. DW1), and then obtained its chloroplast genome information by next-generation sequencing (NGS). The chloroplast genome is 129,447 bp in length, and the GC content is 35.2%. Repetitive sequences with the length of 30–35 bp account for 1.27% of the total chloroplast genome. The simple sequence repeats are all mononucleotide repeats. Codon usage analysis showed that the genome tended to use codon ending in A/U. By comparing the length of different regions of Trebouxiophyceae genomes, we found that the changes in the length of exons, introns, and intergenic sequences affect the size of genomes. Trebouxiophyceae had an unstable chloroplast genome structure, with IRs repeatedly losing during evolution. Phylogenetic analysis showed that Trebouxiophyceae is paraphyletic, and Trebouxiophyceae sp. DW1 is sister to the clade of Koliella longiseta and Pabia signiensis.
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Weis, V. M., and R. P. Levine. "Differential protein profiles reflect the different lifestyles of symbiotic and aposymbiotic Anthopleura elegantissima, a sea anemone from temperate waters." Journal of Experimental Biology 199, no. 4 (1996): 883–92. http://dx.doi.org/10.1242/jeb.199.4.883.
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Mutualistic associations are prevalent in virtually all environments yet relatively little is known about their complex biochemical and molecular integration and regulation. The endosymbiosis between cnidarians such as the sea anemone Anthopleura elegantissima and the photosynthetic dinoflagellate Symbiodinium californium, in which the algal symbionts are housed in vacuoles within animal endodermal cells, is an ideal model for the study of highly integrated associations at the biochemical and molecular levels. This study describes differential protein synthesis between symbiotic A. elegantissima, collected from environments with high levels of light in the intertidal zone and A. elegantissima that naturally lack symbionts (aposymbiotic), collected from nearby deep-shade habitats. Two-dimensional gel electrophoresis profiles of both steady-state and newly synthesized proteins were compared between the two types of animals using scanning densitometry and image analysis. Symbiotic and aposymbiotic animals share a majority of proteins; however, striking differences in several abundant proteins in steady-state profiles occur. Two proteins are unique to symbiotic animals, one at 32 kDa with an isoelectric point (pI) of 7.9 and another at 31 kDa, pI 6.3. Levels of six proteins with an apparent molecular mass of 25 kDa and pI values ranging from 4.8 to 5.5 are greatly enhanced in aposymbiotic animals. Furthermore, profiles of newly synthesized proteins from symbiotic animals contain a unique cluster of proteins ranging from 25 to 30 kDa and pI 6.6 to 6.9. These marked differences in protein profiles must be a reflection either of underlying differences in the regulation of gene expression or in post-translational modification of common proteins. Identifying the symbiosis-specific products present in A. elegantissima and identifying the inter-partner signaling and cues that result in differential expression will provide an insight into the understanding of these highly integrated associations.
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Sazima, Ivan, and Alice Grossman. "Turtle riders: remoras on marine turtles in Southwest Atlantic." Neotropical Ichthyology 4, no. 1 (2006): 123–26. http://dx.doi.org/10.1590/s1679-62252006000100014.
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An overview is presented for a poorly documented relationship between reef vertebrates in Southwest Atlantic: remoras (Echeneidae) associated with marine turtles. Two remora species (Echeneis naucrates and Remora remora) and four turtle species (Caretta caretta, Chelonia mydas, Eretmochelys imbricata, and Dermochelys coriacea) are here recorded in symbiotic associations in the SW Atlantic. Echeneis naucrates was recorded both on the coast and on oceanic islands, whereas R. remora was recorded only at oceanic islands and in the open sea. The remora-turtle association is usually regarded as an instance of phoresis (hitchhiking), albeit feeding by the fish is also involved in this symbiosis type. This association seems to be rare in SW Atlantic.
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Bennett, Gordon M., and Nancy A. Moran. "Heritable symbiosis: The advantages and perils of an evolutionary rabbit hole." Proceedings of the National Academy of Sciences 112, no. 33 (2015): 10169–76. http://dx.doi.org/10.1073/pnas.1421388112.
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Many eukaryotes have obligate associations with microorganisms that are transmitted directly between generations. A model for heritable symbiosis is the association of aphids, a clade of sap-feeding insects, and Buchnera aphidicola, a gammaproteobacterium that colonized an aphid ancestor 150 million years ago and persists in almost all 5,000 aphid species. Symbiont acquisition enables evolutionary and ecological expansion; aphids are one of many insect groups that would not exist without heritable symbiosis. Receiving less attention are potential negative ramifications of symbiotic alliances. In the short run, symbionts impose metabolic costs. Over evolutionary time, hosts evolve dependence beyond the original benefits of the symbiosis. Symbiotic partners enter into an evolutionary spiral that leads to irreversible codependence and associated risks. Host adaptations to symbiosis (e.g., immune-system modification) may impose vulnerabilities. Symbiont genomes also continuously accumulate deleterious mutations, limiting their beneficial contributions and environmental tolerance. Finally, the fitness interests of obligate heritable symbionts are distinct from those of their hosts, leading to selfish tendencies. Thus, genes underlying the host–symbiont interface are predicted to follow a coevolutionary arms race, as observed for genes governing host–pathogen interactions. On the macroevolutionary scale, the rapid evolution of interacting symbiont and host genes is predicted to accelerate host speciation rates by generating genetic incompatibilities. However, degeneration of symbiont genomes may ultimately limit the ecological range of host species, potentially increasing extinction risk. Recent results for the aphid–Buchnera symbiosis and related systems illustrate that, whereas heritable symbiosis can expand ecological range and spur diversification, it also presents potential perils.
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Zykova, A. V., and V. N. Mikheev. "Coral Fish in Symbiotic Associations: Benefits and Risks." Biology Bulletin Reviews 8, no. 1 (2018): 58–66. http://dx.doi.org/10.1134/s2079086418010073.
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Voronin, D., D. A. N. Cook, A. Steven, and M. J. Taylor. "Autophagy regulates Wolbachia populations across diverse symbiotic associations." Proceedings of the National Academy of Sciences 109, no. 25 (2012): E1638—E1646. http://dx.doi.org/10.1073/pnas.1203519109.
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Nascimento, Francisco X., Clarisse Brígido, Bernard R. Glick, and Márcio J. Rossi. "The Role of Rhizobial ACC Deaminase in the Nodulation Process of Leguminous Plants." International Journal of Agronomy 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/1369472.
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Symbiotic rhizobia-legumes associations are extremely important in terms of sustainable agricultural practices. This symbiosis involves a complex interaction between both partners, plant and bacterium, for bacterial infection and the formation of symbiotic N-fixing nodules. In this regard, the phytohormone ethylene plays a significant role in nodule formation, acting as an inhibitor of the nodulation process. Ethylene not only regulates nodule development but also regulates many other plant developmental cues, including various stress responses that inhibit overall plant growth. Some rhizobia produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, thus, being able to decrease ACC and, consequently, decrease deleterious ethylene levels that affect the nodulation process. This occurs because ACC is the immediate precursor of ethylene in all higher plants. Hence, rhizobia that express this enzyme have an increased symbiotic potential. In addition to the direct role that ACC deaminase plays in the nodulation processper se, in a limited number of instances, ACC deaminase can also modulate nodule persistence. This review focuses on the important role of rhizobial ACC deaminase during the nodulation process, emphasizing its significance to legume growth promotion.
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Kazmierczak, Théophile, Marianna Nagymihály, Florian Lamouche, et al. "Specific Host-Responsive Associations Between Medicago truncatula Accessions and Sinorhizobium Strains." Molecular Plant-Microbe Interactions® 30, no. 5 (2017): 399–409. http://dx.doi.org/10.1094/mpmi-01-17-0009-r.
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Legume plants interact with rhizobia to form nitrogen-fixing root nodules. Legume-rhizobium interactions are specific and only compatible rhizobia and plant species will lead to nodule formation. Even within compatible interactions, the genotype of both the plant and the bacterial symbiont will impact on the efficiency of nodule functioning and nitrogen-fixation activity. The model legume Medicago truncatula forms nodules with several species of the Sinorhizobium genus. However, the efficiency of these bacterial strains is highly variable. In this study, we compared the symbiotic efficiency of Sinorhizobium meliloti strains Sm1021, 102F34, and FSM-MA, and Sinorhizobium medicae strain WSM419 on the two widely used M. truncatula accessions A17 and R108. The efficiency of the interactions was determined by multiple parameters. We found a high effectiveness of the FSM-MA strain with both M. truncatula accessions. In contrast, specific highly efficient interactions were obtained for the A17-WSM419 and R108-102F34 combinations. Remarkably, the widely used Sm1021 strain performed weakly on both hosts. We showed that Sm1021 efficiently induced nodule organogenesis but cannot fully activate the differentiation of the symbiotic nodule cells, explaining its weaker performance. These results will be informative for the selection of appropriate rhizobium strains in functional studies on symbiosis using these M. truncatula accessions, particularly for research focusing on late stages of the nodulation process.
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Korzhavina, Oksana A., Darya Y. Grishina, Xingru Chen, Diego Fontaneto, and Viatcheslav N. Ivanenko. "Diving into Diversity: Copepod Crustaceans in Octocoral Associations." Diversity 15, no. 11 (2023): 1140. http://dx.doi.org/10.3390/d15111140.
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This research provides an extensive analysis of the biodiversity and distribution patterns of copepod crustaceans associated with octocoral species. A comprehensive dataset comprising 966 records pertaining to 233 copepod species, encompassing 54 genera, 18 families, and 3 orders, was compiled from 92 scientific papers published between 1858 and 2023, and updated as open data to GBIF. These copepods were found to be closely associated with 183 octocoral species, representing 72 genera and 28 families. The analysis revealed a total of 393 distinct interspecific associations between copepods, classified under the orders Cyclopoida, Harpacticoida, and Siphonostomatoida, and diverse octocorals. Approximately 60% of these associations were reported only once in the literature, which poses challenges to assessing the level of host specificity among the majority of copepod species linked with octocorals. Notably, over 91% of the recorded copepod species were found at depths not exceeding 30 m, with only four copepod species reported at greater depths surpassing 500 m. The presence of these symbiotic copepods was documented across 215 sampling sites situated within 8 of the 12 defined marine ecoregions, with particular attention to the Western Indo-Pacific, Central Indo-Pacific, and Temperate Northern regions. Despite the comprehensive examination of available data, this study highlights substantial gaps in our comprehension of copepod crustacean diversity and distribution in association with octocorals. Moreover, crucial information concerning symbiotic copepods is conspicuously absent for approximately 94% of potential octocoral host species. These disparities emphasize the imperative need for further scientific inquiry to unveil the intricacies of symbiotic relationships and to contribute to a more holistic understanding of copepod–octocoral associations.
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Liu, Jinyuan, Laura A. Blaylock, and Maria J. Harrison. "cDNA arrays as a tool to identify mycorrhiza-regulated genes: identification of mycorrhiza-induced genes that encode or generate signaling molecules implicated in the control of root growth." Canadian Journal of Botany 82, no. 8 (2004): 1177–85. http://dx.doi.org/10.1139/b04-048.
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Arbuscular mycorrhizas (AM) are symbiotic associations formed by fungi from the Glomeromycota and most angiosperms. Despite the widespread occurrence of the association, its ecological significance, and its potential importance in agriculture, relatively little is known at the molecular level about the development, functioning, and regulation of the symbiosis. We have selected Medicago truncatula Gaertn. 'Jemalong' and an AM fungus, Glomus versiforme (Karsten) Berch, for molecular genetic analyses of the AM symbiosis. Here we used macroarrays as a screening tool to enable the rapid identification of genes that show differential expression in mycorrhizal roots. Forty-three genes showing increased transcript levels and 18 genes showing decreased transcripts in mycorrhizal roots were identified. This set contained several genes predicted to encode regulatory proteins including an alpha-fucosidase implicated in the generation of signaling molecules that modulate plant growth and a gene encoding a putative peptide also implicated in the control of plant growth.Key words: legume, symbiosis, arbuscular mycorrhizal fungi.
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Gwokyalya, Rehemah, Christopher W. Weldon, Jeremy Keith Herren, et al. "Friend or Foe: Symbiotic Bacteria in Bactrocera dorsalis–Parasitoid Associations." Biology 12, no. 2 (2023): 274. http://dx.doi.org/10.3390/biology12020274.
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Parasitoids are promising biocontrol agents of the devastating fruit fly, Bactrocera dorsalis. However, parasitoid performance is a function of several factors, including host-associated symbiotic bacteria. Providencia alcalifaciens, Citrobacter freundii, and Lactococcus lactis are among the symbiotic bacteria commonly associated with B. dorsalis, and they influence the eco-physiological functioning of this pest. However, whether these bacteria influence the interaction between this pest and its parasitoids is unknown. This study sought to elucidate the nature of the interaction of the parasitoids, Fopius arisanus, Diachasmimorpha longicaudata, and Psyttlia cosyrae with B. dorsalis as mediated by symbiotic bacteria. Three types of fly lines were used: axenic, symbiotic, and bacteria-mono-associated (Lactococcus lactis, Providencia alcalifaciens, and Citrobacter freundii). The suitable stages of each fly line were exposed to the respective parasitoid species and reared until the emergence of adult flies/parasitoids. Thereafter, data on the emergence and parasitoid fitness traits were recorded. No wasps emerged from the fly lines exposed to P. cosyrae. The highest emergence of F. arisanus and D. longicaudata was recorded in the L. lactis fly lines. The parasitoid progeny from the L. lactis and P. alcalifaciens fly lines had the longest developmental time and the largest body size. Conversely, parasitoid fecundity was significantly lower in the L. lactis lines, whereas the P. alcalifaciens lines significantly improved fecundity. These results elucidate some effects of bacterial symbionts on host–parasitoid interactions and their potential in enhancing parasitoid-oriented management strategies against B. dorsalis.
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Nelsen, Matthew P., Robert Lücking, C. Kevin Boyce, H. Thorsten Lumbsch, and Richard H. Ree. "The macroevolutionary dynamics of symbiotic and phenotypic diversification in lichens." Proceedings of the National Academy of Sciences 117, no. 35 (2020): 21495–503. http://dx.doi.org/10.1073/pnas.2001913117.
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Symbioses are evolutionarily pervasive and play fundamental roles in structuring ecosystems, yet our understanding of their macroevolutionary origins, persistence, and consequences is incomplete. We traced the macroevolutionary history of symbiotic and phenotypic diversification in an iconic symbiosis, lichens. By inferring the most comprehensive time-scaled phylogeny of lichen-forming fungi (LFF) to date (over 3,300 species), we identified shifts among symbiont classes that broadly coincided with the convergent evolution of phylogenetically or functionally similar associations in diverse lineages (plants, fungi, bacteria). While a relatively recent loss of lichenization in Lecanoromycetes was previously identified, our work instead suggests lichenization was abandoned far earlier, interrupting what had previously been considered a direct switch between trebouxiophycean and trentepohlialean algal symbionts. Consequently, some of the most diverse clades of LFF are instead derived from nonlichenized ancestors and re-evolved lichenization with Trentepohliales algae, a clade that also facilitated lichenization in unrelated lineages of LFF. Furthermore, while symbiont identity and symbiotic phenotype influence the ecology and physiology of lichens, they are not correlated with rates of lineage birth and death, suggesting more complex dynamics underly lichen diversification. Finally, diversification patterns of LFF differed from those of wood-rotting and ectomycorrhizal taxa, likely reflecting contrasts in their fundamental biological properties. Together, our work provides a timeline for the ecological contributions of lichens, and reshapes our understanding of symbiotic persistence in a classic model of symbiosis.
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DRAGOTA, Marina, and Stefana JURCOANE. "THE EVOLUTION OF MYCORISIAN FUNG AS SYMBIOTIC PARTNERS." Annals of the Academy of Romanian Scientists Series on Agriculture Silviculture and Veterinary Medicine 11, no. 2 (2022): 69–76. http://dx.doi.org/10.56082/annalsarsciagr.2022.2.69.
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The article analyzes the evolution of mycorrhizal fungi, which served as symbiotic partners in association with plants, more precisely with their root system. The advantage brought by the existence of mycorrhizal symbioses for plant nutrition, highlighted the influence this association has on plant growth and development. The existence of mycorrhizal fungi was demonstrated approximately 400 million years ago, the first discoveries being the fossils of Aglaophyton major plants that showed traces of arbuscules, these being considered edifying transfer structures for the vesicular-arbuscular endomycorrhizal type. Mycorrhizae are present in mature ecosystems, ecosystems that present a cyclical and unitary evolution of the components between the biotic and abiotic unit, at which point the mycorrhizal associations have the role of regulating the assimilation of food resources for the plants with which they are associated. In this association, hyphae play an important role in the nutrient cycle, having the function of stopping losses from the ecosystem
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Perret, Xavier, Christian Staehelin, and William J. Broughton. "Molecular Basis of Symbiotic Promiscuity." Microbiology and Molecular Biology Reviews 64, no. 1 (2000): 180–201. http://dx.doi.org/10.1128/mmbr.64.1.180-201.2000.
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SUMMARY Eukaryotes often form symbioses with microorganisms. Among these, associations between plants and nitrogen-fixing bacteria are responsible for the nitrogen input into various ecological niches. Plants of many different families have evolved the capacity to develop root or stem nodules with diverse genera of soil bacteria. Of these, symbioses between legumes and rhizobia (Azorhizobium, Bradyrhizobium, Mesorhizobium, and Rhizobium) are the most important from an agricultural perspective. Nitrogen-fixing nodules arise when symbiotic rhizobia penetrate their hosts in a strictly controlled and coordinated manner. Molecular codes are exchanged between the symbionts in the rhizosphere to select compatible rhizobia from pathogens. Entry into the plant is restricted to bacteria that have the “keys” to a succession of legume “doors”. Some symbionts intimately associate with many different partners (and are thus promiscuous), while others are more selective and have a narrow host range. For historical reasons, narrow host range has been more intensively investigated than promiscuity. In our view, this has given a false impression of specificity in legume-Rhizobium associations. Rather, we suggest that restricted host ranges are limited to specific niches and represent specialization of widespread and more ancestral promiscuous symbioses. Here we analyze the molecular mechanisms governing symbiotic promiscuity in rhizobia and show that it is controlled by a number of molecular keys.
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Gianinazzi-Pearson, Vivienne, Armelle Gollotte, Benoit Tisserant, et al. "Cellular and molecular approaches in the characterization of symbiotic events in functional arbuscular mycorrhizal associations." Canadian Journal of Botany 73, S1 (1995): 526–32. http://dx.doi.org/10.1139/b95-292.
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Arbuscular mycorrhizas represent the most widespread, and probably most ancient, type of plant–fungus association in which the large majority of terrestrial plants must have evolved with compatibility systems towards the fungal symbionts. Cellular interactions leading to reciprocal morphofunctional integration between symbionts during mycorrhiza establishment are complex. Some plant genes and cellular events may be shared with nodulation processes, but there is evidence of molecular modifications specific to arbuscular mycorrhiza formation. Plant defence responses, which are normally weakly activated during the symbiotic state, are strongly elicited by arbuscular mycorrhizal fungi in genetically altered, resistant hosts suggesting control over defence gene expression during establishment of a successful symbiosis. Modifications are also induced in the fungal symbionts during colonization of host tissues, with changes in wall metabolism and protein expression. Nothing is known of the genetic make-up of arbuscular mycorrhizal fungi which are recalcitrant to pure culture. Recent cloning of DNA from these fungi opens the possibility of identifying functional genes in order to study their regulation and role in symbiosis establishment. Key words: arbuscular mycorrhiza, reciprocal symbiosis, molecular mechanisms, plant determinants, fungal molecules.
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Davis, Catherine V., Jack O. Shaw, Simon D’haenens, Ellen Thomas, and Pincelli M. Hull. "Photosymbiont associations persisted in planktic foraminifera during early Eocene hyperthermals at Shatsky Rise (Pacific Ocean)." PLOS ONE 17, no. 9 (2022): e0267636. http://dx.doi.org/10.1371/journal.pone.0267636.
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Understanding the sensitivity of species-level responses to long-term warming will become increasingly important as we look towards a warmer future. Here, we examine photosymbiont associations in planktic foraminifera at Shatsky Rise (ODP Site 1209, Pacific Ocean) across periods of global warming of differing magnitude and duration. We compare published data from the Paleocene-Eocene Thermal Maximum (PETM; ~55.9 Ma) with data from the less intense Eocene Thermal Maximum 2 (ETM2; ~54.0 Ma), and H2 events (~53.9 Ma). We use a positive relationship between test size and carbon isotope value (size-δ13C) in foraminifera shells as a proxy for photosymbiosis in Morozovella subbotinae and Acarinina soldadoensis, and find no change in photosymbiont associations during the less intense warming events, in contrast with PETM records indicating a shift in symbiosis in A. soldadoensis (but not M. subbotinae). Declines in abundance and differing preservation potential of the asymbiotic species Subbotina roesnaesensis along with sediment mixing likely account for diminished differences in δ13C between symbiotic and asymbiotic species from the PETM and ETM2. We therefore conclude that photosymbiont associations were maintained in both A. soldadoensis and M. subbotinae across ETM2 and H2. Our findings support one or both of the hypotheses that 1) changing symbiotic associations in response to warming during the PETM allowed A. soldadoensis and perhaps other acarininids to thrive through subsequent hyperthermals or 2) some critical environmental threshold value was not reached in these less intense hyperthermals.
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Pernice, Mathieu, Silke Wetzel, Olivier Gros, Renata Boucher-Rodoni, and Nicole Dubilier. "Enigmatic dual symbiosis in the excretory organ of Nautilus macromphalus (Cephalopoda: Nautiloidea)." Proceedings of the Royal Society B: Biological Sciences 274, no. 1614 (2007): 1143–52. http://dx.doi.org/10.1098/rspb.2006.0353.
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Symbiosis is an important driving force in metazoan evolution and the study of ancient lineages can provide an insight into the influence of symbiotic associations on morphological and physiological adaptations. In the ‘living fossil’ Nautilus , bacterial associations are found in the highly specialized pericardial appendage. This organ is responsible for most of the excretory processes (ultrafiltration, reabsorption and secretion) and secretes an acidic ammonia-rich excretory fluid. In this study, we show that Nautilus macromphalus pericardial appendages harbour a high density of a β-proteobacterium and a coccoid spirochaete using transmission electron microscopy, comparative 16S rRNA sequence analysis and fluorescence in situ hybridization (FISH). These two bacterial phylotypes are phylogenetically distant from any known bacteria, with ammonia-oxidizing bacteria as the closest relatives of the β-proteobacterium (above or equal to 87.5% sequence similarity) and marine Spirochaeta species as the closest relatives of the spirochaete (above or equal to 89.8% sequence similarity), and appear to be specific to Nautilus . FISH analyses showed that the symbionts occur in the baso-medial region of the pericardial villi where ultrafiltration and reabsorption processes take place, suggesting a symbiotic contribution to the excretory metabolism.
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Goyal, Ravinder K., Maria Augusta Schmidt, and Michael F. Hynes. "Molecular Biology in the Improvement of Biological Nitrogen Fixation by Rhizobia and Extending the Scope to Cereals." Microorganisms 9, no. 1 (2021): 125. http://dx.doi.org/10.3390/microorganisms9010125.
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The contribution of biological nitrogen fixation to the total N requirement of food and feed crops diminished in importance with the advent of synthetic N fertilizers, which fueled the “green revolution”. Despite being environmentally unfriendly, the synthetic versions gained prominence primarily due to their low cost, and the fact that most important staple crops never evolved symbiotic associations with bacteria. In the recent past, advances in our knowledge of symbiosis and nitrogen fixation and the development and application of recombinant DNA technology have created opportunities that could help increase the share of symbiotically-driven nitrogen in global consumption. With the availability of molecular biology tools, rapid improvements in symbiotic characteristics of rhizobial strains became possible. Further, the technology allowed probing the possibility of establishing a symbiotic dialogue between rhizobia and cereals. Because the evolutionary process did not forge a symbiotic relationship with the latter, the potential of molecular manipulations has been tested to incorporate a functional mechanism of nitrogen reduction independent of microbes. In this review, we discuss various strategies applied to improve rhizobial strains for higher nitrogen fixation efficiency, more competitiveness and enhanced fitness under unfavorable environments. The challenges and progress made towards nitrogen self-sufficiency of cereals are also reviewed. An approach to integrate the genetically modified elite rhizobia strains in crop production systems is highlighted.
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Goyal, Ravinder K., Maria Augusta Schmidt, and Michael F. Hynes. "Molecular Biology in the Improvement of Biological Nitrogen Fixation by Rhizobia and Extending the Scope to Cereals." Microorganisms 9, no. 1 (2021): 125. http://dx.doi.org/10.3390/microorganisms9010125.
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The contribution of biological nitrogen fixation to the total N requirement of food and feed crops diminished in importance with the advent of synthetic N fertilizers, which fueled the “green revolution”. Despite being environmentally unfriendly, the synthetic versions gained prominence primarily due to their low cost, and the fact that most important staple crops never evolved symbiotic associations with bacteria. In the recent past, advances in our knowledge of symbiosis and nitrogen fixation and the development and application of recombinant DNA technology have created opportunities that could help increase the share of symbiotically-driven nitrogen in global consumption. With the availability of molecular biology tools, rapid improvements in symbiotic characteristics of rhizobial strains became possible. Further, the technology allowed probing the possibility of establishing a symbiotic dialogue between rhizobia and cereals. Because the evolutionary process did not forge a symbiotic relationship with the latter, the potential of molecular manipulations has been tested to incorporate a functional mechanism of nitrogen reduction independent of microbes. In this review, we discuss various strategies applied to improve rhizobial strains for higher nitrogen fixation efficiency, more competitiveness and enhanced fitness under unfavorable environments. The challenges and progress made towards nitrogen self-sufficiency of cereals are also reviewed. An approach to integrate the genetically modified elite rhizobia strains in crop production systems is highlighted.
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Moné, Yves, David Monnin, and Natacha Kremer. "The oxidative environment: a mediator of interspecies communication that drives symbiosis evolution." Proceedings of the Royal Society B: Biological Sciences 281, no. 1785 (2014): 20133112. http://dx.doi.org/10.1098/rspb.2013.3112.
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Symbiotic interactions are ubiquitous in nature and play a major role in driving the evolution of life. Interactions between partners are often mediated by shared signalling pathways, which strongly influence both partners' biology and the evolution of the association in various environments. As an example of ‘common language’, the regulation of the oxidative environment plays an important role in driving the evolution of symbiotic associations. Such processes have been occurring for billions of years, including the increase in Earth's atmospheric oxygen and the subsequent evolution of mitochondria. The effect of reactive oxygen species and reactive nitrogen species (RONS) has been characterized functionally, but the molecular dialogue between partners has not been integrated within a broader evolutionary context yet. Given the pleiotropic role of RONS in cell–cell communication, development and immunity, but also their associated physiological costs, we discuss here how their regulation can influence the establishment, the maintenance and the breakdown of various symbiotic associations. By synthesizing recent developments in redox biology, we aim to provide an interdisciplinary understanding of the influence of such mediators of interspecies communication on the evolution and stability of symbioses, which in turn can shape ecosystems and play a role in health and disease.
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Luciński, Robert, Władysław Polcyn, and Lech Ratajczak. "Nitrate reduction and nitrogen fixation in symbiotic association Rhizobium-legumes." Acta Biochimica Polonica 49, no. 2 (2002): 537–46. http://dx.doi.org/10.18388/abp.2002_3813.
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The inhibitory effect of nitrate on nitrogenase activity in root nodules of legume plants has been known for a long time. The major factor inducing changes in nitrogenase activity is the concentration of free oxygen inside nodules. Oxygen availability in the infected zone of nodule is limited, among others, by the gas diffusion resistance in nodule cortex. The presence of nitrate may cause changes in the resistance to O2 diffusion. The aim of this paper is to review literature data concerning the effect of nitrate on the symbiotic association between rhizobia and legume plants, with special emphasis on nitrogenase activity. Recent advances indicate that symbiotic associations of Rhizobium strains characterized by a high nitrate reductase activity are less susceptible to inhibition by nitrate. A thesis may be put forward that dissimilatory nitrate reduction, catalyzed by bacteroid nitrate reductase, significantly facilitates the symbiotic function of bacteroids.
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Zou, Yanfen, and Bifan Cai. "Models and Mechanisms of Effective Rural Operation for Promoting Common Prosperity: A Longitudinal Case Study of the "Guzhu Model" from a Symbiotic Perspective." Global Academic Frontiers 3, no. 2 (2025): 189–202. https://doi.org/10.5281/zenodo.15583223.
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Achieving common prosperity for all people is the essential requirement of Chinese-style modernization, and the weakest key link at present is the common prosperity of farmers and rural areas. Taking Guzhu Village in Changxing County as a typical case, this paper adopts the longitudinal single case study method to explore the process, operation mode and mechanism of the village's road to common prosperity from the perspective of symbiosis theory. The results show that: (1) Guzhu Village has experienced different stages of development in the process of common prosperity, and each stage has produced different symbiotic effects. Individual villagers have given birth to the bud of rural development, but their lack of knowledge, cognition and management ability can't achieve high-quality rural development. The gradual participation of the government, associations and operating companies has injected new energy into promoting rural areas towards common prosperity. (2) The village focuses on multiple symbiotic subjects and operates collaboratively with the help of symbiotic environment. Effective collaboration between symbiotic units has become the key to rural common prosperity. The symbiotic model respects the core position of villagers, effectively promotes the participation and recognition of all villagers, turns the ecological advantages and resource advantages in the village into economic advantages and development advantages, and realizes the villagers' material wealth, spiritual and cultural wealth and ecological harmony in the village. Research suggestions: In the process of rural development, we can inject new energy into the village by maintaining the dominant position of villagers, introducing new units such as operating companies, making full use of resource endowments to broaden the path of increasing income and getting rich, giving full play to the synergy among symbiotic units, and jointly strengthening the rural collective economy.
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Mies, M., C. R. Voolstra, C. B. Castro, D. O. Pires, E. N. Calderon, and P. Y. G. Sumida. "Expression of a symbiosis-specific gene in Symbiodinium type A1 associated with coral, nudibranch and giant clam larvae." Royal Society Open Science 4, no. 5 (2017): 170253. http://dx.doi.org/10.1098/rsos.170253.
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Symbiodinium are responsible for the majority of primary production in coral reefs and found in a mutualistic symbiosis with multiple animal phyla. However, little is known about the molecular signals involved in the establishment of this symbiosis and whether it initiates during host larval development. To address this question, we monitored the expression of a putative symbiosis-specific gene (H + -ATPase) in Symbiodinium A1 ex hospite and in association with larvae of a scleractinian coral ( Mussismilia hispida ), a nudibranch ( Berghia stephanieae ) and a giant clam ( Tridacna crocea ). We acquired broodstock for each host, induced spawning and cultured the larvae. Symbiodinium cells were offered and larval samples taken for each host during the first 72 h after symbiont addition. In addition, control samples including free-living Symbiodinium and broodstock tissue containing symbionts for each host were collected. RNA extraction and RT-PCR were performed and amplified products cloned and sequenced. Our results show that H + -ATPase was expressed in Symbiodinium associated with coral and giant clam larvae, but not with nudibranch larvae, which digested the symbionts. Broodstock tissue for coral and giant clam also expressed H + -ATPase, but not the nudibranch tissue sample. Our results of the expression of H + -ATPase as a marker gene suggest that symbiosis between Symbiodinium and M. hispida and T. crocea is established during host larval development. Conversely, in the case of B. stephanieae larvae, evidence does not support a mutualistic relationship. Our study supports the utilization of H + -ATPase expression as a marker for assessing Symbiodinium– invertebrate relationships with applications for the differentiation of symbiotic and non-symbiotic associations. At the same time, insights from a single marker gene approach are limited and future studies should direct the identification of additional symbiosis-specific genes, ideally from both symbiont and host.
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Lee, Jun-Ki, Ahn-Heum Eom, and Sang-Sun Lee. "Multiple Symbiotic Associations Found in the Roots ofBotrychium ternatum." Mycobiology 30, no. 3 (2002): 146. http://dx.doi.org/10.4489/myco.2002.30.3.146.
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Fujihara, Shinsuke, Hiroto Abe, Yasuo Minakawa, Shoichiro Akao, and Tadakatsu Yoneyama. "Polyamines in Nodules from Various Plant-Microbe Symbiotic Associations." Plant and Cell Physiology 35, no. 8 (1994): 1127–34. http://dx.doi.org/10.1093/oxfordjournals.pcp.a078705.
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Lema, Kimberley A., Bette L. Willis, and David G. Bourne. "Corals Form Characteristic Associations with Symbiotic Nitrogen-Fixing Bacteria." Applied and Environmental Microbiology 78, no. 9 (2012): 3136–44. http://dx.doi.org/10.1128/aem.07800-11.
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ABSTRACTThe complex symbiotic relationship between corals and their dinoflagellate partnerSymbiodiniumis believed to be sustained through close associations with mutualistic bacterial communities, though little is known about coral associations with bacterial groups able to fix nitrogen (diazotrophs). In this study, we investigated the diversity of diazotrophic bacterial communities associated with three common coral species (Acropora millepora,Acropora muricata, andPocillopora damicormis) from three midshelf locations of the Great Barrier Reef (GBR) by profiling the conserved subunit of thenifHgene, which encodes the dinitrogenase iron protein. Comparisons of diazotrophic community diversity among coral tissue and mucus microenvironments and the surrounding seawater revealed that corals harbor diversenifHphylotypes that differ between tissue and mucus microhabitats. Coral mucusnifHsequences displayed high heterogeneity, and many bacterial groups overlapped with those found in seawater. Moreover, coral mucus diazotrophs were specific neither to coral species nor to reef location, reflecting the ephemeral nature of coral mucus. In contrast, the dominant diazotrophic bacteria in tissue samples differed among coral species, with differences remaining consistent at all three reefs, indicating that coral-diazotroph associations are species specific. Notably, dominant diazotrophs for all coral species were closely related to the bacterial group rhizobia, which represented 71% of the total sequences retrieved from tissue samples. The species specificity of coral-diazotroph associations further supports the coral holobiont model that bacterial groups associated with corals are conserved. Our results suggest that, as in terrestrial plants, rhizobia have developed a mutualistic relationship with corals and may contribute fixed nitrogen toSymbiodinium.
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Crowell, Robert M. "Two unusual water mite symbiotic associations in New Zealand." SIL Proceedings, 1922-2010 23, no. 4 (1988): 2035–37. http://dx.doi.org/10.1080/03680770.1987.11899841.
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Saffo, M. B. "Themes from Variation: Probing the Commonalities of Symbiotic Associations." Integrative and Comparative Biology 42, no. 2 (2002): 291–94. http://dx.doi.org/10.1093/icb/42.2.291.
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Boursaux-Eude, Caroline, and Roy Gross. "New insights into symbiotic associations between ants and bacteria." Research in Microbiology 151, no. 7 (2000): 513–19. http://dx.doi.org/10.1016/s0923-2508(00)00221-7.
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Pirlo, S. D., R. D. Johnson, C. R. Voisey, A. Koulman, and G. T. Bryan. "Heterologous synthesis of the fungal alkaloid peramine." NZGA: Research and Practice Series 13 (January 1, 2007): 483. http://dx.doi.org/10.33584/rps.13.2006.3131.
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