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1
Benson, David R., James M. Brooks, Ying Huang, Derek M. Bickhart et Juliana E. Mastronunzio. « The Biology of Frankia sp. Strains in the Post-Genome Era ». Molecular Plant-Microbe Interactions® 24, no 11 (novembre 2011) : 1310–16. http://dx.doi.org/10.1094/mpmi-06-11-0150.
Texte intégralRésumé :
Progress in understanding symbiotic determinants involved in the N2-fixing actinorhizal plant symbioses has been slow but steady. Problems persist with studying the bacterial contributions to the symbiosis using traditional microbiological techniques. However, recent years have seen the emergence of several genomes from Frankia sp. strains and the development of techniques for manipulating plant gene expression. Approaches to understanding the bacterial side of the symbiosis have employed a range of techniques that reveal the proteomes and transcriptomes from both cultured and symbiotic frankiae. The picture beginning to emerge provides some perspective on the heterogeneity of frankial populations in both conditions. In general, frankial populations in root nodules seem to maintain a rather robust metabolism that includes nitrogen fixation and substantial biosynthesis and energy-generating pathways, along with a modified ammonium assimilation program. To date, particular bacterial genes have not been implicated in root nodule formation but some hypotheses are emerging with regard to how the plant and microorganism manage to coexist. In particular, frankiae seem to present a nonpathogenic presence to the plant that may have the effect of minimizing some plant defense responses. Future studies using high-throughput approaches will likely clarify the range of bacterial responses to symbiosis that will need to be understood in light of the more rapidly advancing work on the plant host.
2
Popovici, Jean, Gilles Comte, �milie Bagnarol, Nicole Alloisio, Pascale Fournier, Floriant Bellvert, C�dric Bertrand et 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, no 8 (26 février 2010) : 2451–60. http://dx.doi.org/10.1128/aem.02667-09.
Texte intégralRésumé :
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.
3
Popovici, Jean, Vincent Walker, Cédric Bertrand, Floriant Bellvert, Maria P. Fernandez et Gilles Comte. « Strain specificity in the Myricaceae - Frankia symbiosis is correlated to plant root phenolics ». Functional Plant Biology 38, no 9 (2011) : 682. http://dx.doi.org/10.1071/fp11144.
Texte intégralRésumé :
Plant secondary metabolites play an important role in the interaction between plants and their environment. For example, mutualistic nitrogen-fixing symbioses typically involve phenolic-based recognition between host plants and bacteria. Although 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 the actinobacterium Frankia. In this study, the responsiveness of two Myricaceae plant species, Myrica gale L. and Morella cerifera L., to Frankia inoculation was correlated with the plant–bacteria compatibility status. Two Frankia strains were inoculated: ACN14a, compatible with both M. gale and M. cerifera and Ea112, compatible only with M. cerifera. The effect of inoculation on root phenolic metabolism was evaluated by metabolic profiling based on high-performance liquid chromatography (HPLC) and principal component analysis (PCA). Our results revealed that: (i) both Frankia strains induced major modifications in root phenolic content of the two Myricaceae species and (ii) strain-dependant modifications of the phenolic contents were detected. The main plant compounds differentially affected by Frankia inoculation are phenols, flavonoids and hydroxycinnamic acids. This work provides evidence that during the initial phases of symbiotic interactions, Myricaceae plants adapt their secondary metabolism in accordance with the compatibility status of Frankia bacterial strains.
4
Berg, R. Howard. « Frankia forms infection threads ». Canadian Journal of Botany 77, no 9 (18 décembre 1999) : 1327–33. http://dx.doi.org/10.1139/b99-073.
Texte intégralRésumé :
Frankia forms symbioses with a great variety of plant hosts, and because nodule development is under plant control, this results in an interesting diversity in the structure of developing symbiotic cells. However, it is apparent that, in all these symbioses, the microsymbiont Frankia follows a similar pattern of development within symbiotic cells of the nodule: the cell is invaded by formation of an infection thread containing invasive hyphae sheathed in plant cell wall material, parasitic vegetative hyphae proliferate by branching from this infection thread, and N2-fixing symbiotic vesicles differentiate from tips of these vegetative hyphae. Infection threads are recognized by their ontogeny and morphology, being the cell-invasive structures in the case of the former and straight-growing hyphae in the case of the latter. Formation of infection threads is a feature shared in common with legumes. Unlike in legumes, the infection thread in actinorhizae is not defined by the presence of sheathing plant cell wall material; all forms of the bacterium have this. Rather than using the term "encapsulation," which suggests a bacterial origin, it is proposed the term "interfacial matrix" be used to describe this plant cell wall material separating Frankia from host cytoplasm.Key words: Frankia, infection thread, interfacial matrix, microsymbiont, nodule, symbiosis.
5
Mastronunzio, J. E., Y. Huang et D. R. Benson. « Diminished Exoproteome of Frankia spp. in Culture and Symbiosis ». Applied and Environmental Microbiology 75, no 21 (11 septembre 2009) : 6721–28. http://dx.doi.org/10.1128/aem.01559-09.
Texte intégralRésumé :
ABSTRACT Frankia species are the most geographically widespread gram-positive plant symbionts, carrying out N2 fixation in root nodules of trees and woody shrubs called actinorhizal plants. Taking advantage of the sequencing of three Frankia genomes, proteomics techniques were used to investigate the population of extracellular proteins (the exoproteome) from Frankia, some of which potentially mediate host-microbe interactions. Initial two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of culture supernatants indicated that cytoplasmic proteins appeared in supernatants as cells aged, likely because older hyphae lyse in this slow-growing filamentous actinomycete. Using liquid chromatography coupled to tandem mass spectrometry to identify peptides, 38 proteins were identified in the culture supernatant of Frankia sp. strain CcI3, but only three had predicted export signal peptides. In symbiotic cells, 42 signal peptide-containing proteins were detected from strain CcI3 in Casuarina cunninghamiana and Casuarina glauca root nodules, while 73 and 53 putative secreted proteins containing signal peptides were identified from Frankia strains in field-collected root nodules of Alnus incana and Elaeagnus angustifolia, respectively. Solute-binding proteins were the most commonly identified secreted proteins in symbiosis, particularly those predicted to bind branched-chain amino acids and peptides. These direct proteomics results complement a previous bioinformatics study that predicted few secreted hydrolytic enzymes in the Frankia proteome and provide direct evidence that the symbiosis succeeds partly, if not largely, because of a benign relationship.
6
Anne-Emmanuelle, Hay, Boubakri Hasna, Buonomo Antoine, Rey Marjolaine, Meiffren Guillaume, Cotin-Galvan Laetitia, Comte Gilles et Herrera-Belaroussi Aude. « Control of Endophytic Frankia Sporulation by Alnus Nodule Metabolites ». Molecular Plant-Microbe Interactions® 30, no 3 (mars 2017) : 205–14. http://dx.doi.org/10.1094/mpmi-11-16-0235-r.
Texte intégralRésumé :
A unique case of microbial symbiont capable of dormancy within its living host cells has been reported in actinorhizal symbioses. Some Frankia strains, named Sp+, are able to sporulate inside plant cells, contrarily to Sp− strains. The presence of metabolically slowed-down bacterial structures in host cells alters our understanding of symbiosis based on reciprocal benefits between both partners, and its impact on the symbiotic processes remains unknown. The present work reports a metabolomic study of Sp+ and Sp− nodules (from Alnus glutinosa), in order to highlight variabilities associated with in-planta sporulation. A total of 21 amino acids, 44 sugars and organic acids, and 213 secondary metabolites were detected using UV and mass spectrometric–based profiling. Little change was observed in primary metabolites, suggesting that in-planta sporulation would not strongly affect the primary functionalities of the symbiosis. One secondary metabolite (M27) was detected only in Sp+ nodules. It was identified as gentisic acid 5-O-β-d-xylopyranoside, previously reported as involved in plant defenses against microbial pathogens. This metabolite significantly increased Frankia in-vitro sporulation, unlike another metabolite significantly more abundant in Sp− nodules [M168 = (5R)-1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-O-β-d-glucopyranoside]. All these results suggest that the plant could play an important role in the Frankia ability to sporulate in planta and allow us to discuss a possible sanction emitted by the host against less cooperative Sp+ symbionts.
7
Markham, John H., et Chris P. Chanway. « Does past contact reduce the degree of mutualism in the Alnus rubra - Frankia symbiosis ? » Canadian Journal of Botany 77, no 3 (20 août 1999) : 434–41. http://dx.doi.org/10.1139/b98-227.
Texte intégralRésumé :
Although most vascular plants have symbiotic relationships with soil microbes, and there is an extensive theoretical literature on the evolution of mutualism, there has been little experimental examination of the evolution of mutualism between plants and their microbial symbionts. We inoculated red alder (Alnus rubra Bong.) seedlings from three high- and three low-elevation populations with crushed nodule suspensions containing the nitrogen fixing bacterium Frankia from either the parent trees (familiar strains) or the other plant population sampled within the parent watershed (unfamiliar strains). The inoculated seedlings were planted on three high- and three low-elevation sites. Growth was monitored over the second and third year following planting, after which the whole plants were harvested. The proportion of nitrogen derived from fixation was estimated from the ratio of stable nitrogen isotopes in the harvested leaves. On low-elevation sites, which had high soil nitrogen, plants with familiar Frankia strains were half the size and derived less fixed nitrogen from their symbionts compared with plants inoculated with unfamiliar Frankia strains. On high-elevation sites, which had low soil nitrogen, the type of inoculum had little effect on plant performance, although plants with familiar inoculum were consistently larger than plants with unfamiliar inoculum. These results suggest that the degree of mutualism in this symbiosis depends on environmental conditions and may decrease with time.Key words: coevolution, Frankia, Alnus rubra, mutualism, nitrogen fixation, symbiosis.
8
Pujic, Petar, Nicole Alloisio, Guylaine Miotello, Jean Armengaud, Danis Abrouk, Pascale Fournier et Philippe Normand. « The Proteogenome of Symbiotic Frankia alni in Alnus glutinosa Nodules ». Microorganisms 10, no 3 (18 mars 2022) : 651. http://dx.doi.org/10.3390/microorganisms10030651.
Texte intégralRésumé :
Omics are the most promising approaches to investigate microbes for which no genetic tools exist such as the nitrogen-fixing symbiotic Frankia. A proteogenomic analysis of symbiotic Frankia alni was done by comparing those proteins more and less abundant in Alnus glutinosa nodules relative to N2-fixing pure cultures with propionate as the carbon source. There were 250 proteins that were significantly overabundant in nodules at a fold change (FC) ≥ 2 threshold, and 1429 with the same characteristics in in vitro nitrogen-fixing pure culture. Nitrogenase, SuF (Fe–Su biogenesis) and hopanoid lipids synthesis determinants were the most overabundant proteins in symbiosis. Nitrogenase was found to constitute 3% of all Frankia proteins in nodules. Sod (superoxide dismutase) was overabundant, indicating a continued oxidative stress, while Kats (catalase) were not. Several transporters were overabundant including one for dicarboxylates and one for branched amino acids. The present results confirm the centrality of nitrogenase in the actinorhizal symbiosis.
9
Ribeiro, Ana, Inês Graça, Katharina Pawlowski et Patrícia Santos. « Actinorhizal plant defence-related genes in response to symbiotic Frankia ». Functional Plant Biology 38, no 9 (2011) : 639. http://dx.doi.org/10.1071/fp11012.
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Actinorhizal plants have become increasingly important as climate changes threaten to remake the global landscape over the next decades. These plants are able to grow in nutrient-poor and disturbed soils, and are important elements in plant communities worldwide. Besides that, most actinorhizal plants are capable of high rates of nitrogen fixation due to their capacity to establish root nodule symbiosis with N2-fixing Frankia strains. Nodulation is a developmental process that requires a sequence of highly coordinated events. One of these mechanisms is the induction of defence-related events, whose precise role in a symbiotic interaction remains to be elucidated. This review summarises what is known about the induction of actinorhizal defence-related genes in response to symbiotic Frankia and their putative function during symbiosis.
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Wilkinson, Helen, Alice Coppock, Bethany L. Richmond, Beatriz Lagunas et Miriam L. Gifford. « Plant–Environment Response Pathway Regulation Uncovered by Investigating Non-Typical Legume Symbiosis and Nodulation ». Plants 12, no 10 (12 mai 2023) : 1964. http://dx.doi.org/10.3390/plants12101964.
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Nitrogen is an essential element needed for plants to survive, and legumes are well known to recruit rhizobia to fix atmospheric nitrogen. In this widely studied symbiosis, legumes develop specific structures on the roots to host specific symbionts. This review explores alternate nodule structures and their functions outside of the more widely studied legume–rhizobial symbiosis, as well as discussing other unusual aspects of nodulation. This includes actinorhizal-Frankia, cycad-cyanobacteria, and the non-legume Parasponia andersonii-rhizobia symbioses. Nodules are also not restricted to the roots, either, with examples found within stems and leaves. Recent research has shown that legume–rhizobia nodulation brings a great many other benefits, some direct and some indirect. Rhizobial symbiosis can lead to modifications in other pathways, including the priming of defence responses, and to modulated or enhanced resistance to biotic and abiotic stress. With so many avenues to explore, this review discusses recent discoveries and highlights future directions in the study of nodulation.
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Berry, Alison M., Alberto Mendoza-Herrera, Ying-Yi Guo, Jennifer Hayashi, Tomas Persson, Ravi Barabote, Kirill Demchenko, Shuxiao Zhang et Katharina Pawlowski. « New perspectives on nodule nitrogen assimilation in actinorhizal symbioses ». Functional Plant Biology 38, no 9 (2011) : 645. http://dx.doi.org/10.1071/fp11095.
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Nitrogen-fixing root nodules are plant organs specialised for symbiotic transfer of nitrogen and carbon between microsymbiont and host. The organisation of nitrogen assimilation, storage and transport processes is partitioned at the subcellular and tissue levels, in distinctive patterns depending on the symbiotic partners. In this review, recent advances in understanding of actinorhizal nodule nitrogen assimilation are presented. New findings indicate that Frankia within nodules of Datisca glomerata (Presl.) Baill. carries out both primary nitrogen assimilation and biosynthesis of arginine, rather than exporting ammonium. Arginine is a typical storage form of nitrogen in plant tissues, but is a novel nitrogen carrier molecule in root nodule symbioses. Thus Frankia within D. glomerata nodules exhibits considerable metabolic independence. Furthermore, nitrogen reassimilation is likely to take place in the host in the uninfected nodule cortical cells of this root nodule symbiosis, before amino acid export to host sink tissues via the xylem. The role of an augmented pericycle in carbon and nitrogen exchange in root nodules deserves further attention in actinorhizal symbiosis, and further highlights the importance of a comprehensive, structure–function approach to understanding function in root nodules. Moreover, the multiple patterns of compartmentalisation in relation to nitrogen flux within root nodules demonstrate the diversity of possible functional interactions between host and microsymbiont that have evolved in the nitrogen-fixing clade.
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Alloisio, Nicole, Clothilde Queiroux, Pascale Fournier, Petar Pujic, Philippe Normand, David Vallenet, Claudine Médigue, Masatoshi Yamaura, Kentaro Kakoi et Ken-ichi Kucho. « The Frankia alni Symbiotic Transcriptome ». Molecular Plant-Microbe Interactions® 23, no 5 (mai 2010) : 593–607. http://dx.doi.org/10.1094/mpmi-23-5-0593.
Texte intégralRésumé :
The actinobacteria Frankia spp. are able to induce the formation of nodules on the roots of a large spectrum of actinorhizal plants, where they convert dinitrogen to ammonia in exchange for plant photosynthates. In the present study, transcriptional analyses were performed on nitrogen-replete free-living Frankia alni cells and on Alnus glutinosa nodule bacteria, using whole-genome microarrays. Distribution of nodule-induced genes on the genome was found to be mostly over regions with high synteny between three Frankia spp. genomes, while nodule-repressed genes, which were mostly hypothetical and not conserved, were spread around the genome. Genes known to be related to nitrogen fixation were highly induced, nif (nitrogenase), hup2 (hydrogenase uptake), suf (sulfur-iron cluster), and shc (hopanoids synthesis). The expression of genes involved in ammonium assimilation and transport was strongly modified, suggesting that bacteria ammonium assimilation was limited. Genes involved in particular in transcriptional regulation, signaling processes, protein drug export, protein secretion, lipopolysaccharide, and peptidoglycan biosynthesis that may play a role in symbiosis were also identified. We also showed that this Frankia symbiotic transcriptome was highly similar among phylogenetically distant plant families Betulaceae and Myricaceae. Finally, comparison with rhizobia transcriptome suggested that F. alni is metabolically more active in symbiosis than rhizobia.
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Gabbarini, Luciano Andrés, et Luis Gabriel Wall. « Diffusible factors from Frankia modify nodulation kinetics in Discaria trinervis, an intercellular root-infected actinorhizal symbiosis ». Functional Plant Biology 38, no 9 (2011) : 662. http://dx.doi.org/10.1071/fp11015.
Texte intégralRésumé :
Frankia BCU110501 induces nitrogen-fixing root nodules in Discaria trinervis (Gillies ex Hook. & Arn.) Reiche (Rhamnaceae) via intercellular colonisation, without root hair deformation. It produces diffusible factors (DFs) that might be involved in early interactions with the D. trinervis roots, playing a role in the nodulation process. The induction of root nodule development in actinorhizal symbiosis would depend on the concentration of factors produced by the bacteria and the plant. A detailed analysis of nodulation kinetics revealed that these DFs produce changes at the level of initial rate of nodulation and also in nodulation profile. Diluted Frankia BCU110501 inoculum could be activated in less than 96 h by DFs produced by Frankia BCU110501 cells that had been previously washed. Biochemical characterisation showed that Frankia BCU110501 DFs have a molecular weight of <12 kDa, are negatively charged at pH 7.0 and seem to contain a peptide bond necessary for their activity. Frankia BCU110501, belonging to Frankia Clade 3, does not induce nodules in Alnus acuminata H.B.K. ssp. acuminata but is able to deform root hairs, as do Frankia strains from Clade 1. The root hair deforming activity of Frankia BCU110501 DFs show the same biochemical characteristics of the DFs involved in nodulation of D. trinervis. These results suggest that Frankia symbiotic factors have a basic structure regardless of the infection pathway of the host plant.
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Zimpfer, J. F., G. J. Kennedy, C. A. Smyth, J. Hamelin, E. Navarro et J. O. Dawson. « Localization ofCasuarina-infectiveFrankianearCasuarina cunninghamianatrees in Jamaica ». Canadian Journal of Botany 77, no 9 (18 décembre 1999) : 1248–56. http://dx.doi.org/10.1139/b99-063.
Texte intégralRésumé :
Soil sampled along a 100-m linear series of plots extending from the stems of three Casuarina cunninghamiana Miq. trees was bioassayed to estimate the number of infective units (IU) of the symbiotic diazotroph Frankia per gram of soil using native Myrica cerifera L. and exotic C. cunninghamiana as Frankia traps. Casuarina-infective Frankia was detected only in soils within 20 m of Casuarina host trees. Myrica-infective Frankia was found in all of the plots assayed even though none of the native M. cerifera occurred on or near the site. Polymerase chain reaction - restriction fragment length polymorphism characterization of nodule microsymbiont DNA from both host species indicates that Casuarina were nodulated by a different group of Frankia than the groups nodulating Myrica. The Casuarina-infective Frankia is in the same taxonomic group as most other Casuarina-infective Frankia found where Casuarina trees were introduced outside of Australia. Soil collected near the C. cunninghamiana trees had higher total N, NO3, organic matter, P, Mg, K, Ca, pH, and cation exchange capacity. Homogenates ofC. cunninghamiana leaves and stems increased the number of IUs of Frankia CjI82 001 when inoculated and incubated for 3 months in an artificial soil. Thus, it seems that C. cunninghamiana is able to alter soil chemical properties and possibly favor its specific microsymbiont in soil.Key words: Frankia, Casuarina, Myrica, symbiosis, allelopathy, N-fixation.
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Pawlowski, Katharina, Didier Bogusz, Ana Ribeiro et Alison M. Berry. « Progress on research on actinorhizal plants ». Functional Plant Biology 38, no 9 (2011) : 633. http://dx.doi.org/10.1071/fp11066.
Texte intégralRésumé :
In recent years, our understanding of the plant side of actinorhizal symbioses has evolved rapidly. No homologues of the common nod genes from rhizobia were found in the three Frankia genomes published so far, which suggested that Nod factor-like molecules would not be used in the infection of actinorhizal plants by Frankia. However, work on chimeric transgenic plants indicated that Frankia Nod factor equivalents signal via the same transduction pathway as rhizobial Nod factors. The role of auxin in actinorhizal nodule formation differs from that in legume nodulation. Great progress has been made in the analysis of pathogenesis-related and stress-related gene expression in nodules. Research on nodule physiology has shown the structural and metabolic diversity of actinorhizal nodules from different phylogenetic branches. The onset of large-scale nodule transcriptome analysis in different actinorhizal systems will provide access to more information on the symbiosis and its evolution.
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Imanishi, Leandro, Alice Vayssières, Claudine Franche, Didier Bogusz, Luis Wall et Sergio Svistoonoff. « Transformed Hairy Roots of Discaria trinervis : A Valuable Tool for Studying Actinorhizal Symbiosis in the Context of Intercellular Infection ». Molecular Plant-Microbe Interactions® 24, no 11 (novembre 2011) : 1317–24. http://dx.doi.org/10.1094/mpmi-03-11-0078.
Texte intégralRésumé :
Among infection mechanisms leading to root nodule symbiosis, the intercellular infection pathway is probably the most ancestral but also one of the least characterized. Intercellular infection has been described in Discaria trinervis, an actinorhizal plant belonging to the Rosales order. To decipher the molecular mechanisms underlying intercellular infection with Frankia bacteria, we set up an efficient genetic transformation protocol for D. trinervis based on Agrobacterium rhizogenes. We showed that composite plants with transgenic roots expressing green fluorescent protein can be specifically and efficiently nodulated by Frankia strain BCU110501. Nitrogen fixation rates and feedback inhibition of nodule formation by nitrogen were similar in control and composite plants. In order to challenge the transformation system, the MtEnod11 promoter, a gene from Medicago truncatula widely used as a marker for early infection-related symbiotic events in model legumes, was introduced in D. trinervis. MtEnod11::GUS expression was related to infection zones in root cortex and in the parenchyma of the developing nodule. The ability to study intercellular infection with molecular tools opens new avenues for understanding the evolution of the infection process in nitrogen-fixing root nodule symbioses.
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Gabbarini, Luciano Andrés, et Luis Gabriel Wall. « Diffusible factors involved in early interactions of actinorhizal symbiosis are modulated by the host plant but are not enough to break the host range barrier ». Functional Plant Biology 38, no 9 (2011) : 671. http://dx.doi.org/10.1071/fp11003.
Texte intégralRésumé :
Nodulation kinetics were analysed in two nitrogen-fixing actinorhizal symbioses that show different pathways for infection: Alnus acuminata H. B. K., which is infected by Frankia ArI3, and Discaria trinervis (Hooker et Arnot) Reiche, which is infected by Frankia BCU110501. Both pairs are incompatible in cross-inoculation experiments. The dose–response effects in nodulation were studied in A. acuminata seedlings using different concentrations of compatible and incompatible bacteria in co-inoculation experiments. Restriction fragment length polymorphism PCR analysis and plant-trapping analysis showed no co-occupation in A. acuminata nodules when plants were co-inoculated with Frankia BCU110501 and Frankia ArI3. Despite the lack of co-occupation, the noninfective BCU110501 could modify the nodulation parameters of the non-host A. acuminata when infective ArI3 was present in the inoculum. The results suggest that although BCU110501 was not able to induce nodulation in A. acuminata, its interaction with the plant could induce autoregulation as if some level of infection or partial recognition could be achieved. We explored the possibility that physiological complementation of the heterologous Frankia BCU110501 for nodulation of A. acuminata originated in the homologous Frankia ArI3 in the presence of compatible root exudates. Despite the possibility of full activation between bacteria and the host, there was no co-infection of Frankia BCU110501 in Alnus or of Frankia ArI3 in Discaria either. These negative results suggest a physical recognition barrier in actinorhizal symbiosis that operates after early interactions, involving something other than root exudates and diffusible factors of bacterial or plant origin, regardless of the infection pathway.
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Yoo, Won Young, Si Bum Sung et Chung Sun An. « Nucleotide sequences of the 2-oxoacid ferredoxin oxidoreductase and ferredoxin genes fromFrankiastrain EuIK1, a symbiont ofElaeagnus umbellataroot nodules ». Canadian Journal of Botany 77, no 9 (18 décembre 1999) : 1279–86. http://dx.doi.org/10.1139/b99-079.
Texte intégralRésumé :
A genomic clone, pEuNIFII, was isolated by screening a genomic library of Frankia strain EuIK1, a symbiont of Elaeagnus umbellata Thunb. root nodules. A 1.5-kb fragment of pEuNIF4.0, which contained ORF2 and N-terminal part of nifS, was used as a probe. A 7.2-kb BamHI fragment of pEuNIFII, which was proven to be adjacent to the probe, was subjected to sequence determination. The sequence analysis suggested one partial ORF followed by three open reading frames (ORFs). Two ORFs next to nifS encodes an a subunit (672 amino acids) and b subunit (347 amino acids) of a 2-oxoacid ferredoxin oxidoreducatase (OR), respectively. The third ORF encodes 114 amino acids of a 7Fe-type ferredoxin (Fdx). All ORFs are transcribed in the same direction as other nif genes. Alignment of the deduced amino acid sequences from frankiae OR revealed the motifs of gamma and alpha domains seen in other ORs in the a subunit, and the beta domain in the b subunit. Frankia or shows about 44% nucleotide sequence similarity with nifJ from Klebsiella pneumoniae, while frankiae fdx shows about 56% similarity with fdxI from Azotobacter vinelandii. These genes are reported for the first time in Frankia, and putative roles of their products in symbiosis is discussed in relation to nitrogen fixation and carbohydrate metabolism.Key words: 2-oxoacid ferredoxin oxidoreductase, ferredoxin, nucleotide sequence, Frankia EuIK1.
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Benabdoun, Faïza Meriem, Mathish Nambiar-Veetil, Leandro Imanishi, Sergio Svistoonoff, Nadia Ykhlef, Hassen Gherbi et Claudine Franche. « Composite Actinorhizal Plants with Transgenic Roots for the Study of Symbiotic Associations with Frankia ». Journal of Botany 2011 (1 novembre 2011) : 1–8. http://dx.doi.org/10.1155/2011/702947.
Texte intégralRésumé :
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.
20
Valverde, Claudio, et Luis Gabriel Wall. « Regulation of nodulation in Discaria trinervis (Rhamnaceae) - Frankia symbiosis ». Canadian Journal of Botany 77, no 9 (18 décembre 1999) : 1302–10. http://dx.doi.org/10.1139/b99-072.
Texte intégralRésumé :
Nodulation in Discaria trinervis (Hook. et Arn.) Reiche was mainly located around the position of the taproot tip at the moment of inoculation with Frankia. Nodule distribution, but not final level of nodulation, was affected by the inoculum dose and the culture age of Frankia. Taproot inoculation resulted in distal suppression of nodulation of the growing root as early as 3 days after inoculation, that is, before the first nodules could be detected. Systemic inhibition in split root systems was maximal, but not complete, for a delay of 20 days between inoculations on both sides. Reinoculation of 9.5-week-old nodulated D. trinervis plants did not cause further nodulation. Nevertheless, nodule excision, with or without new inoculation, allowed the plant to develop new nodules not only at the infectible region of the young developing root but also in the region of prior existing nodules, where we observed arrested nodules at an early developmental stage. We conclude that root nodulation in D. trinervis might be controlled by two different pathways that operate through inhibition of infection and nodule development. One pathway is activated immediately after the first stages of root cell division are induced because of root inoculation with Frankia. The inhibition becomes systemic and is widespread in the root system before host cell invasion is carried out at the infection sites. The second pathway requires the presence of mature and N2-fixing nodules.Key words: actinorhiza, autoregulation, Discaria trinervis, feedback inhibition, Frankia, intercellular infection.
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Basistha, Bharat C., et Arnab Sen. « Sea buckthorn and its microsymbiont-a review ». NBU Journal of Plant Sciences 5, no 1 (2011) : 67–84. http://dx.doi.org/10.55734/nbujps.2011.v05i01.011.
Texte intégralRésumé :
Hippophae sp. is a versatile plant restricted in distribution to the Himalayas having multipurpose usage including food, fodder, medicine, and controlling soil erosion. Besides, it plays a huge role in increasing the fertility of the soil by harboring symbiotic nitrogen fixing bacteria called Frankia. In this review we have looked into two main aspects of this symbiosis. First we have made a detailed account of the macrosymbiont i.e. Hippophae. Since Hippophae has food and medicinal properties and are widely used in cosmetic production, we excavated the antioxidant activity of various parts of Hippophae including fruits, seeds, bark and leaf. People of Indo-Tibetan plateau adapt a special agro-technique to cultivate Hippophae. The technique has been discussed here. A detail report of this plant including their distribution and various ecological parameters has also been done. On the other hand we have also elucidate about the microsymbiont present in root nodule of Hippophae i.e. Frankia. Frankia is filamentous actinomycetes which fix atmospheric nitrogen to the soil and therefore increase the soil-fertility. A detailed account of morphology. anatomy, phylogeny and ecology of Frankia has been illustrated here. The diversity of Frankia in soil is another interesting topic and the speciation of this bacterium is an everlasting controversy. We have given a closer look to the genetic diversity and phylogenetic relationships of Frankia at intra and inter generic level.
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Sarkar, Indrani. « A conference report on 19th International Meeting on Frankia and Actinorhizal Plants ». NBU Journal of Plant Sciences 11, no 1 (2019) : 124–25. http://dx.doi.org/10.55734/nbujps.2019.v11i01.008.
Texte intégralRésumé :
The 19th International conference on Frankia and Actinorhizal plants which I attended along with one of my colleague Miss Reha Labar was held from 17th-10th March, 2018 at Hammamet, Tunisia Since my research is about Frankia and other actinobacteria, this conference provided a full opportunity to meet with people from different parts of the world who are working on the same topic and also learned some new techniques they are using for better understanding of Frankia and Actinorhizal symbiosis.
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Svistoonoff, Sergio, Laurent Laplaze, Florence Auguy, John Runions, Robin Duponnois, Jim Haseloff, Claudine Franche et Didier Bogusz. « cg12 Expression Is Specifically Linked to Infection of Root Hairs and Cortical Cells during Casuarina glauca and Allocasuarina verticillata Actinorhizal Nodule Development ». Molecular Plant-Microbe Interactions® 16, no 7 (juillet 2003) : 600–607. http://dx.doi.org/10.1094/mpmi.2003.16.7.600.
Texte intégralRésumé :
cg12 is an early actinorhizal nodulin gene from Casuarina glauca encoding a subtilisin-like serine protease. Using transgenic Casuarinaceae plants carrying cg12-gus and cg12-gfp fusions, we have studied the expression pattern conferred by the cg12 promoter region after inoculation with Frankia. cg12 was found to be expressed in root hairs and in root and nodule cortical cells containing Frankia infection threads. cg12 expression was also monitored after inoculation with ineffective Frankia strains, during my-corrhizae formation, and after diverse hormonal treatments. None of these treatments was able to induce its expression, therefore suggesting that cg12 expression is linked to plant cell infection by Frankia strains. Possible roles of cg12 in actinorhizal symbiosis are discussed.
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Myers, Anna K., et Louis S. Tisa. « Isolation of antibiotic-resistant and antimetabolite-resistant mutants ofFrankiastrains EuI1c and Cc1.17 ». Canadian Journal of Microbiology 50, no 4 (1 avril 2004) : 261–67. http://dx.doi.org/10.1139/w04-013.
Texte intégralRésumé :
Antibiotic-resistant and antimetabolite-resistant mutants of the nitrogen-fixing symbiotic bacterium Frankia were isolated to provide strains with genetic backgrounds amenable to genetic analysis. The lethal and mutagenic effects of ethyl methanesulfonate (EMS) and UV light on four Frankia strains were investigated. UV irradiation or EMS treatment of strain EuI1c cells resulted in the formation of two different colony types: rough and smooth. The smooth colonies were conditional sporulation mutants. In the case of EMS-induced cells of strain Cc1.17, resistance to lincomycin, ampicillin, and 5-fluorouracil occurred at a frequency of 1 × 10–5, 1 × 10–5, and 4 × 10–5, respectively. The lincomycin-resistant mutants produced a yellow–tan pigment that was released into the growth medium. Resistance to tetracycline and lincomycin with EMS-induced cells of strain EuI1c occurred at a frequency of 3.2 × 10–3and 4.7 × 10–4, respectively. These strains will be useful for the development of genetic methods for Frankia.Key words: genetics, genetic markers, Frankia, actinorhizal symbiosis, nitrogen fixation, mutagenesis, EMS, UV light.
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Berry, A. M., L. McIntyre et M. E. McCully. « Fine structure of root hair infection leading to nodulation in the Frankia–Alnus symbiosis ». Canadian Journal of Botany 64, no 2 (1 février 1986) : 292–305. http://dx.doi.org/10.1139/b86-043.
Texte intégralRésumé :
Root hair infection by Frankia (Actinomycetales) is the means by which nitrogen-fixing root nodules are initiated upon the actinorhizal host, Alnus rubra. Structural details of the infectious process and the changes in host root hair cells are demonstrated at the prenodule stage for the first time using light and transmission electron microscopy. The Frankia hypha is the infective agent, extending from the rhizosphere through the root hair wall in a highly deformed region of the hair. There is no evidence of pleomorphism of the Frankia hypha. The primary wall fibrils of the root hair appear disorganized at the site of penetration. There is extensive secondary wall formation in the infected hair. At the site of penetration, root hair cell wall ingrowths occur that are structurally consistent with transfer cell wall formation. The ingrowths are continuous with the encapsulating wall layer surrounding the Frankia hypha The host cytoplasm is rich in ribosomes, secretory products, and organelles, including Golgi bodies, mitochondria, plastids, and profiles of endoplasmic reticulum. In an aborted infection sequence, some structural features of the host response to Frankia are observable, while other aspects of successful infection do not occur. Limited transfer cell wall is formed at the site of near infection. The root hair cytoplasm is senescent, however, and a callosic plug appears to surround the pathway of infection.
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Wall, Luis Gabriel, et Kerstin Huss-Danell. « Regulation of nodulation in Alnus incana-Frankia symbiosis ». Physiologia Plantarum 99, no 4 (avril 1997) : 594–600. http://dx.doi.org/10.1111/j.1399-3054.1997.tb05362.x.
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Wall, Luis Gabriel, et Kerstin Huss-Danell. « Regulation of nodulation in Alnus incana-Frankia symbiosis* ». Physiologia Plantarum 99, no 4 (avril 1997) : 594–600. http://dx.doi.org/10.1034/j.1399-3054.1997.990411.x.
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Solans, Mariana. « Discaria trinervis – Frankia symbiosis promotion by saprophytic actinomycetes ». Journal of Basic Microbiology 47, no 3 (juin 2007) : 243–50. http://dx.doi.org/10.1002/jobm.200610244.
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Chen, Haoran, Sylvie Renault et John Markham. « The Effect of Frankia and Hebeloma crustiliniforme on Alnus alnobetula subsp. Crispa Growing in Saline Soil ». Plants 11, no 14 (16 juillet 2022) : 1860. http://dx.doi.org/10.3390/plants11141860.
Texte intégralRésumé :
The mining of the oil sands region of Canada’s boreal forest creates disturbed land with elevated levels of salts. Understanding how native plants respond to salt stress is critical in reclaiming these lands. The native species, Alnus alnobetula subsp. crispa forms nitrogen-fixing nodules with Frankia, and ectomycorrhizae with a number of fungal species. These relationships may make the plant particularly well suited for restoring disturbed land. We inoculated A. alnobetula subsp. crispa with Frankia and Hebeloma crustiliniforme and exposed the plants to 0, 50, or 100 mM NaCl for seven weeks. Frankia-inoculated plants had increased biomass regardless of salt exposure, even though salt exposure reduced nitrogen fixation and reduced the efficiency of nitrogen-fixing nodules. The nitrogen-fixing symbiosis also decreased leaf stress and increased root phosphatase levels. This suggests that N-fixing plants not only have increased nitrogen nutrition but also have increased access to soil phosphorus. Mycorrhizae did not affect plant growth but did reduce nodule numbers and nodule efficiency. These results suggest that the nitrogen-fixing trait is more critical than mycorrhizae. While salt stress inhibits nitrogen-fixing symbiosis, plants still benefit from nitrogen fixation when exposed to salt.
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Baker, Ethan, Yang Tang, Feixia Chu et Louis S. Tisa. « Molecular responses ofFrankiasp. strain QA3 to naphthalene ». Canadian Journal of Microbiology 61, no 4 (avril 2015) : 281–92. http://dx.doi.org/10.1139/cjm-2014-0786.
Texte intégralRésumé :
The Frankia–actinorhizal plant symbiosis plays a significant role in plant colonization in soils contaminated with heavy metals and toxic aromatic hydrocarbons. The molecular response of Frankia upon exposure to soil contaminants is not well understood. To address this issue, we subjected Frankia sp. strain QA3 to naphthalene stress and showed that it could grow on naphthalene as a sole carbon source. Bioinformatic analysis of the Frankia QA3 genome identified a potential operon for aromatic compound degradation as well as several ring-hydroxylating dioxygenases. Under naphthalene stress, the expression of these genes was upregulated. Proteome analysis showed a differential protein profile for cells under naphthalene stress. Several protein spots were analyzed and used to identify proteins involved in stress response, metabolism, and energy production, including a lignostilbene dioxygenase. These results provide a model for understanding the molecular response of Frankia to common soil pollutants, which may be required for survival and proliferation of the bacterium and their hosts in polluted environments.
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Pujic, Petar, Lorena Carro, Pascale Fournier, Jean Armengaud, Guylaine Miotello, Nathalie Dumont, Caroline Bourgeois et al. « Frankia alni Carbonic Anhydrase Regulates Cytoplasmic pH of Nitrogen-Fixing Vesicles ». International Journal of Molecular Sciences 24, no 11 (23 mai 2023) : 9162. http://dx.doi.org/10.3390/ijms24119162.
Texte intégralRésumé :
A phyloprofile of Frankia genomes was carried out to identify those genes present in symbiotic strains of clusters 1, 1c, 2 and 3 and absent in non-infective strains of cluster 4. At a threshold of 50% AA identity, 108 genes were retrieved. Among these were known symbiosis-associated genes such as nif (nitrogenase), and genes which are not know as symbiosis-associated genes such as can (carbonic anhydrase, CAN). The role of CAN, which supplies carbonate ions necessary for carboxylases and acidifies the cytoplasm, was thus analyzed by staining cells with pH-responsive dyes; assaying for CO2 levels in N-fixing propionate-fed cells (that require a propionate-CoA carboxylase to yield succinate-CoA), fumarate-fed cells and N-replete propionate-fed cells; conducting proteomics on N-fixing fumarate and propionate-fed cells and direct measurement of organic acids in nodules and in roots. The interiors of both in vitro and nodular vesicles were found to be at a lower pH than that of hyphae. CO2 levels in N2-fixing propionate-fed cultures were lower than in N-replete ones. Proteomics of propionate-fed cells showed carbamoyl-phosphate synthase (CPS) as the most overabundant enzyme relative to fumarate-fed cells. CPS combines carbonate and ammonium in the first step of the citrulline pathway, something which would help manage acidity and NH4+. Nodules were found to have sizeable amounts of pyruvate and acetate in addition to TCA intermediates. This points to CAN reducing the vesicles’ pH to prevent the escape of NH3 and to control ammonium assimilation by GS and GOGAT, two enzymes that work in different ways in vesicles and hyphae. Genes with related functions (carboxylases, biotin operon and citrulline-aspartate ligase) appear to have undergone decay in non-symbiotic lineages.
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Hay, Anne-Emmanuelle, Aude Herrera-Belaroussi, Marjolaine Rey, Pascale Fournier, Philippe Normand et Hasna Boubakri. « Feedback Regulation of N Fixation in Frankia-Alnus Symbiosis Through Amino Acids Profiling in Field and Greenhouse Nodules ». Molecular Plant-Microbe Interactions® 33, no 3 (mars 2020) : 499–508. http://dx.doi.org/10.1094/mpmi-10-19-0289-r.
Texte intégralRésumé :
Symbiosis established between actinorhizal plants and Frankia spp., which are nitrogen-fixing actinobacteria, promotes nodule organogenesis, the site of metabolic exchange. The present study aimed to identify amino acid markers involved in Frankia-Alnus interactions by comparing nodules and associated roots from field and greenhouse samples. Our results revealed a high level of citrulline in all samples, followed by arginine (Arg), aspartate (Asp), glutamate (Glu), γ-amino-n-butyric acid (GABA), and alanine (Ala). Interestingly, the field metabolome approach highlighted more contrasted amino acid patterns between nodules and roots compared with greenhouse samples. Indeed, 12 amino acids had a mean relative abundance significantly different between field nodule and root samples, against only four amino acids in greenhouse samples, underlining the importance of developing “ecometabolome” approaches. In order to monitor the effects on Frankia cells (respiration and nitrogen fixation activities) of amino acid with an abundance pattern evocative of a role in symbiosis, in-vitro assays were performed by supplementing them in nitrogen-free cultures. Amino acids had three types of effects: i) those used by Frankia as nitrogen source (Glu, Gln, Asp), ii) amino acids stimulating both nitrogen fixation and respiration (e.g., Cit, GABA, Ala, valine, Asn), and iii) amino acids triggering a toxic effect (Arg, histidine). In this paper, a N-metabolic model was proposed to discuss how the host plant and bacteria modulate amino acids contents in nodules, leading to a fine regulation sustaining high bacterial nitrogen fixation.
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Pérez, Néstor-Octavio, Hiram Olivera, Luis Vásquez et María Valdés. « Genetic characterization of MexicanFrankiastrains nodulatingCasuarina equisetifolia ». Canadian Journal of Botany 77, no 9 (18 décembre 1999) : 1214–19. http://dx.doi.org/10.1139/b99-075.
Texte intégralRésumé :
There is a need to increase the utilization of the Casuarina equisetifolia J.R. Forst. & G. Forst. - Frankia symbiosis and be sure of its effectiveness in Mexico. This may be facilitated by selecting appropriate bacterial strains for which ecological characteristics are known. We tested various typing methods to develop genetic markers for ecological studies. DNA, extracted from clonal cultures of native strains or from reference cultures of Casuarina-infective Frankia strains, was used as the template in polymerase chain reactions (PCR) with primers targeting different DNA regions. nifH and 16S rDNA probes from the reference strain Frankia Br were utilized to authenticate the isolates. Polymorphisms of the restricted fragments of the intergenetic spacer between the 16S-23S rDNAs were analyzed. Repetitive extragenic palindromic sequences (rep-PCR) (BOXA1R primer) were used to generate genomic fingerprints. All studied strains showed two copies of the ribosomal operon and a single copy of the nifH gene. PCR - restriction fragment length polymorphism patterns of the 16S-23S intergenetic spacer (IGS) were similar for all Frankia isolates; however, the rep-PCR technique was sensitive enough to distinguish between some of these Frankia strains. The Mexican cultured strains of Frankia nodulating C. equisetifolia appeared to be closely related to the isolated and nodular Frankia from trees growing outside Australia.Key words: Frankia, Casuarina, 16S rRNA, 16S-23S IGS, nifH, repetitive sequence polymerase chain reaction.
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Sasakura, Fuyuko, Toshiki Uchiumi, Yoshikazu Shimoda, Akihiro Suzuki, Katsumi Takenouchi, Shiro Higashi et Mikiko Abe. « A Class 1 Hemoglobin Gene from Alnus firma Functions in Symbiotic and Nonsymbiotic Tissues to Detoxify Nitric Oxide ». Molecular Plant-Microbe Interactions® 19, no 4 (avril 2006) : 441–50. http://dx.doi.org/10.1094/mpmi-19-0441.
Texte intégralRésumé :
Actinorhizal symbiosis is as important in biological nitrogen fixation as legume-rhizobium symbiosis in the global nitrogen cycle. To understand the function of hemoglobin (Hb) in actinorhizal symbiosis, we characterized a Hb of Alnus firma, AfHb1. A cDNA that encodes nonsymbiotic Hb (nonsym-Hb) was isolated from a cDNA library of A. firma nodules probed with LjHb1, a nonsym-Hb of Lotus japonicus. No homolog of symbiotic Hb (sym-Hb) could be identified by screening in the cDNA library or by polymerase chain reaction (PCR) using degenerate primers for other sym-Hb genes. The deduced amino acid sequence of AfHb1 showed 92% sequence similarity with a class 1 nonsym-Hb of Casuarina glauca. Quantitative reverse transcriptase-PCR analysis showed that AfHb1 was expressed strongly in the nodules and enhanced expression was detected under cold stress but not under hypoxia or osmotic stress. Moreover, AfHb1 was strongly induced by the application of nitric oxide (NO) donors, and the application of a NO scavenger suppressed the effect of NO donors. Acetylene reduction was strongly inhibited by the addition of NO donors. AfHb1 may support the nitrogen fixation ability of members of the genus Frankia as a NO scavenger.
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Clawson, Michael L., Jeffrey Gawronski et David R. Benson. « Dominance ofFrankiastrains in stands ofAlnus incanasubsp.rugosaandMyrica pensylvanica ». Canadian Journal of Botany 77, no 9 (18 décembre 1999) : 1203–7. http://dx.doi.org/10.1139/b99-070.
Texte intégralRésumé :
To address issues of dominance and diversity of Frankia spp. strains, we sequenced 16S rRNA genes from root nodules and strains collected from Alnus incana subsp. rugosa (Du Roi) R.T. Clausen and Myrica pensylvanica Loisel. stands. Of 22 strains isolated previously from A. incana, 16 had the same partial rDNA sequence; the remaining 6 strains composed five additional groups. The groups identified by 16S rDNA analysis corresponded to phenotypic groups established previously by one- and two-dimensional polyacrylamide gel analysis, colony and hyphal morphology, and carbon source utilization patterns. Dominance of one strain was also evident in nodules collected from a single M. pensylvanica stand. The dominant strain had a partial 16S rDNA sequence identical to that of Frankia alni strain CpI1.Key words: Frankia, Myrica, Alnus, actinorhizal, root nodules, nitrogen fixation, symbiosis, 16S rRNA.
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Ribeiro, Ana, Alison M. Berry, Katharina Pawlowski et Patrícia Santos. « Actinorhizal plants ». Functional Plant Biology 38, no 9 (2011) : v. http://dx.doi.org/10.1071/fpv38n9_fo.
Texte intégralRésumé :
Actinorhizal plants are a group of taxonomically diverse angiosperms with remarkable economic and ecological significance. Most actinorhizal plants are able to thrive under extreme adverse environmental conditions as well as to fix atmospheric nitrogen due to their capacity to establish root nodule symbioses with Frankia bacteria. This special issue of Functional Plant Biology is dedicated to actinorhizal plant research, covering part of the work presented at the 16th International Meeting onFrankia and Actinorhizal Plants, held on 5–8 September 2010, in Oporto, Portugal. The papers (4 reviews and 10 original articles) give an overall picture of the status of actinorhizal plant research and the imposed challenges, covering several aspects of the symbiosis, ecology and molecular tools.
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Gueddou, Abdellatif, Imed Sbissi, Moussa Louati, Faten Ghodhbane-Gtari, Hafsa Cherif-Silini et Maher Gtari. « Root Nodule Microsymbionts of Native Coriaria myrtifolia in Algeria ». Microbiology Insights 15 (janvier 2022) : 117863612211337. http://dx.doi.org/10.1177/11786361221133794.
Texte intégralRésumé :
Coriaria myrtifolia occurs as natural flora of warm temperate climates of northern Algeria which commonly found in hedges, forest and ravine edges. This actinorhizal species was known to establish a mutualistic symbiosis with members of phylogenetic cluster 2 (including strains associated to Coriaria spp., Ceanothus, Datiscaceae, and Dryadoideae) within the genus Frankia. Attempts to isolate C. myrtifolia microsymbionts from native plants growing in 4 locations in Algeria permitted to only recover asymbiotic Frankia strains (unable to reestablish nodulation and to fix nitrogen) from phylogenetic cluster 4 and several non- Frankia actinobacteria including members of Micrococcus, Micromonospora, Nocardia, Plantactinospora, and Streptomyces genera. The biodiversity of Frankia microsymbionts of C. myrtifolia root nodules was assessed using PCR-amplification followed by partial nucleotide sequencing of glnA1 (glutamine synthetase type 1) gene. On the 12 different glnA1 gene sequences obtained in this study, 9 were detected for the first time, and were mainly closelyrelated to Mediterranean genotypes previously described in the Grand Maghreb countries (Morocco and Tunisia) and in Europe (France) but without clear separations from other cluster 2 genotypes.
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Maity, Pooja Jha, et Katharina Pawlowski. « Anthropogenic influences on the distribution of the Casuarina-Frankia symbiosis ». Symbiosis 84, no 3 (28 mars 2021) : 353–67. http://dx.doi.org/10.1007/s13199-021-00765-5.
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GREITNER, CAROL S., et WILLIAM E. WINNER. « Effects of O3 on alder photosynthesis and symbiosis with Frankia ». New Phytologist 111, no 4 (avril 1989) : 647–56. http://dx.doi.org/10.1111/j.1469-8137.1989.tb02359.x.
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Chen, Li-hong, Jian Liu, Gui-min Yao et Wei Yan. « Genetic diversity ofFrankiastrains in root nodules fromHippophae¨ rhamnoidesL. » Botany 86, no 3 (mars 2008) : 240–47. http://dx.doi.org/10.1139/b07-133.
Texte intégralRésumé :
The Hippophae¨ rhamnoides L. – Frankia symbiosis is of ecological and practical importance, but very little is known about H. rhamnoides-infective Frankia strains. To address this problem, we have used PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of nifD–nifK intergenic spacer (IGS) to estimate their genetic diversity at 19 sites in Northern China. Restriction analysis indicated that H. rhamnoides-infective Frankia had a high genetic diversity; the samples were divided into nine RFLP patterns (A–I). Elevation and precipitation likely affect the distribution of different Frankia patterns in root nodules. The patterns A and D were present in relatively large areas, which were located at various elevations; however, the distribution of patterns B, C, E, F, G, H, and I generally followed a geographic range. The richness of Frankia diversity was influenced by plant cover and geographic factors such as elevation and precipitation. H. rhamnoides cover had a higher diversity than that of natural vegetation cover. The center part of the geographical range, with intermediate elevation and precipitation, had a higher level of Frankia diversity than that of the west part and east part with high or low elevations and precipitations, respectively. The nifD–nifK IGS regions were sequenced from 28 nodule samples. Phylogenetic analysis showed that H. rhamnoides-infective Frankia strains were all clustered with the Elaeagnus group, and the diversity of this group was quite extensive. Phylogenetic relationships between Hippophae¨ and Elaeagnus-infective Frankia strains were relatively close to each other. Although not very close to either Hippophae¨- or Elaeagnus-infective Frankia strains, Shepherdia -infective strain SCN10a was closer to Hippophae¨-infective strains than to Elaeagnus- infective strains. This is the first detailed report on the genetic diversity and phylogenetic analysis of H. rhamnoides-infective Frankia.
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Roy, Sébastien, Damase P. Khasa et Charles W. Greer. « Combining alders, frankiae, and mycorrhizae for the revegetation and remediation of contaminated ecosystems ». Canadian Journal of Botany 85, no 3 (mars 2007) : 237–51. http://dx.doi.org/10.1139/b07-017.
Texte intégralRésumé :
Alder shrubs and trees that are capable of forming symbioses with mycorrhizal fungi and the nitrogen-fixing actinomycete Frankia sp. are particularly hardy species found worldwide in harsh and nutrient-deficient ecosystems. The mycorrhizal symbiosis may assist alders in nutrient and water uptake, while the actinorhizal symbiosis provides assimilable nitrogen. It is through these highly efficient symbioses, in which microsymbionts benefit from plant photosynthates, that actinorhizal plants such as alders colonize poor substrates, enrich soil, and initiate plant succession. These natural capabilities, combined with careful screening of microsymbionts and host plants, may prove useful for the rehabilitation of disturbed ecosystems. Although alders have been used extensively at industrial scales in forestry, nurse planting, and contaminated land revegetation, relatively little research has focussed on their actinorhizal and mycorrhizal plant–microbe interactions in contaminated environments. To study such a topic is, however, critical to the successful development of phytotechnologies, and to understand the impact of anthropogenic stress on these organisms. In this review, we discuss two alder-based phytotechnologies that hold promise: the stimulation of organic contaminant biodegradation (rhizodegradation) by soil microflora in the presence of alders, and the phytostabilization of inorganic contaminants. We also summarize the plant–microbe interactions that characterize alders, and discuss important issues related to the study of actinorhizal and (or) mycorrhizal alders for the rehabilitation of disturbed soils.
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Schrader, James A., et William R. Graves. « Nodulation and Growth of Alnus nitida and Alnus maritima Inoculated with Species-specific and Nonspecific Frankia ». Journal of Environmental Horticulture 26, no 1 (1 mars 2008) : 29–34. http://dx.doi.org/10.24266/0738-2898-26.1.29.
Texte intégralRésumé :
Abstract Actinorhizal plants form N2-fixing symbioses with soil-borne bacteria of the genus Frankia. Potential exists for development of sustainable, actinorhizal nursery crops that obtain most of their required N through N2 fixation, but information on host-symbiont specificity, presence of compatible Frankia in soils, and techniques to inoculate during plant production is lacking. Our objectives were to determine the effect of inoculum type and source and the effect of supplemental N on nodulation, growth, and N content of two actinorhizal species, Alnus nitida (Spach) Endl. and Alnus maritima (Marsh.) Muhl. ex Nutt. Plants of both species were subjected to one of four inoculum treatments (two crushed-nodule inocula: species-specific and cross inoculation, and two soil inocula: soil collected beneath native Alnus rubra Bong. in Washington state and native prairie soil from Iowa), were supplied fertilizer with or without N, and were grown in a greenhouse for 22 weeks. Inoculated plants nodulated, grew larger and faster, and accrued greater N content than uninoculated controls in both fertilizer treatments. Plants that received species-specific inoculum grew larger, acquired more dry weight from symbioses, and accumulated higher N content than cross-inoculated plants. Plants of A. nitida inoculated with soil from Washington state grew larger and accumulated more dry weight from symbioses than those inoculated with prairie soil, but A. maritima grew similarly with soil inoculum from both sources. Our results demonstrate that A. nitida and A. maritima can benefit from N2-fixing symbiosis during production and that potential exists for development of superior inocula and inoculation techniques.
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Auguy, Florence, Khalid Abdel-Lateif, Patrick Doumas, Pablo Badin, Vanessa Guerin, Didier Bogusz et Valérie Hocher. « Activation of the isoflavonoid pathway in actinorhizal symbioses ». Functional Plant Biology 38, no 9 (2011) : 690. http://dx.doi.org/10.1071/fp11014.
Texte intégralRésumé :
We investigated the involvement of flavonoids in the actinorhizal nodulation process resulting from the interaction between the tropical tree Casuarina glauca Sieb. ex Spreng. and the actinomycete Frankia. Eight C. glauca genes involved in flavonoid biosynthesis: chalcone synthase (CHS), chalcone isomerase (CHI), isoflavone reductase (IFR), flavonoid-3-hydroxylase (F3H), flavonoid 3′-hydroxylase (F3′H), flavonoid 3′,5′ hydroxylase (F3′5′H), dihydroflavonol 4-reductase (DFR) and flavonol synthase (FLS), were identified from a unigene database and gene expression patterns were monitored by quantitative real-time PCR (qRT–PCR) during the nodulation time course. Results showed that FLS and F3′5′H transcripts accumulated in mature nodules whereas CHI and IFR transcripts accumulated preferentially early after inoculation with Frankia. Comparison of IFR and CHI expression in inoculated plants and in control plants cultivated with or without nitrogen confirmed that early expression of IFR is specifically linked to symbiosis. Taken together, these data suggest for the first time that isoflavonoids are implicated in actinorhizal nodulation.
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Bélanger, Pier-Anne, Jean-Philippe Bellenger et Sébastien Roy. « Strong modulation of nutrient distribution in Alnus glutinosa as a function of the actinorhizal symbiosis ». Botany 91, no 4 (avril 2013) : 218–24. http://dx.doi.org/10.1139/cjb-2012-0184.
Texte intégralRésumé :
Micro- and macro-nutrient acquisition by plants and microorganisms is a cornerstone for their survival and has a direct impact on biogeochemical cycling. In this study, we investigated, in controlled conditions, how the availability of exogenous nitrate impacted nutrient acquisition and distribution in black alder (Alnus glutinosa (L.) Gaertn.) in the presence, or absence, of its nitrogen-fixing bacterial symbiont (Frankia sp.). Our findings show that alder physiology and distribution of nutrients between aerial and root tissues were strongly influenced by the presence of the symbiont. In both nodulated and non-nodulated alders, root allocation and total plant biomass were positively correlated, except when nodulated alders were subjected to low nitrate conditions (≤15 ppm). Alders receiving 45 ppm exogenous nitrate had a less developed actinorhizal symbiosis. These findings reflect the importance of root exploration in relation to plant dependence to exogenous nitrate. Nutrient composition of alder aerial tissues, in particular molybdenum, was significantly altered in the presence of Frankia. In the context of plant leaf-litter mutualism involving metals and N exchange, our findings of high Mo and P translocation to shoots of non-nodulated alders underscores how the state of the symbiosis in actinorhizal plants can influence the biogeochemical cycling of elements.
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Berg, R. Howard. « Cytoplasmic bridge formation in the nodule apex of actinorhizal root nodules ». Canadian Journal of Botany 77, no 9 (18 décembre 1999) : 1351–57. http://dx.doi.org/10.1139/b99-078.
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High-pressure frozen - freeze-substituted actinorhizal root nodules of several distantly related plant genera were used to document the sequence of structural changes in cortical cells of the nodule apex that happened prior to their infection. The sequence of mobilization of the plant cell cytoplasm requisite to infection by Frankia was (i) penetration of the parenchyma cell vacuole by cytoplasmic strands, which contained microtubules; (ii) movement of the nucleus and other organelles (Golgi stacks, endoplasmic reticulum, mitochondria), involved later in growth of the infection thread, to the cell center on these strands; (iii) thickening of some of these strands generally located at midpoints of the wall, forming cytoplasmic bridges (preinfection threads); and (iv) infection of the cell by initiation of infection threads (containing Frankia) within the cytoplasmic bridges. The infection thread was caged in microtubules that were oriented along its axis, suggesting the cytoskeleton had a major role in the infection process, perhaps guiding the growth of the infection thread across the cell. The coalignment of cytoplasmic bridges, along several cells, towards the advancing microsymbiont suggested Frankia secretes a diffusible signal eliciting this host response.Key words: actinorhiza, cryofixation, development, infection, microtubules, symbiosis.
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VALVERDE, CLAUDIO, et LUIS GABRIEL WALL. « Time course of nodule development in the Discaria trinervis (Rhamnaceae) -Frankia symbiosis ». New Phytologist 141, no 2 (février 1999) : 345–54. http://dx.doi.org/10.1046/j.1469-8137.1999.00345.x.
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Pawlowski, Katharina, Susan Swensen, Changhui Guan, Az-Eddine Hadri, Alison M. Berry et Ton Bisseling. « Distinct Patterns of Symbiosis-Related Gene Expression in Actinorhizal Nodules from Different Plant Families ». Molecular Plant-Microbe Interactions® 16, no 9 (septembre 2003) : 796–807. http://dx.doi.org/10.1094/mpmi.2003.16.9.796.
Texte intégralRésumé :
Phylogenetic analyses suggest that, among the members of the Eurosid I clade, nitrogen-fixing root nodule symbioses developed multiple times independently, four times with rhizobia and four times with the genus Frankia. In order to understand the degree of similarity between symbiotic systems of different phylogenetic subgroups, gene expression patterns were analyzed in root nodules of Datisca glomerata and compared with those in nodules of another actinorhizal plant, Alnus glutinosa, and with the expression patterns of homologous genes in legumes. In parallel, the phylogeny of actinorhizal plants was examined more closely. The results suggest that, although relationships between major groups are difficult to resolve using molecular phylogenetic analysis, the comparison of gene expression patterns can be used to inform evolutionary relationships. In this case, stronger similarities were found between legumes and intracellularly infected actinorhizal plants (Alnus) than between actinorhizal plants of two different phylogenetic subgroups (Alnus/Datisca).
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Salgado, Marco Guedes, Irina V. Demina, Pooja Jha Maity, Anurupa Nagchowdhury, Andrea Caputo, Elizaveta Krol, Christoph Loderer, Günther Muth, Anke Becker et Katharina Pawlowski. « Legume NCRs and nodule-specific defensins of actinorhizal plants—Do they share a common origin ? » PLOS ONE 17, no 8 (18 août 2022) : e0268683. http://dx.doi.org/10.1371/journal.pone.0268683.
Texte intégralRésumé :
The actinorhizal plant Datisca glomerata (Datiscaceae, Cucurbitales) establishes a root nodule symbiosis with actinobacteria from the earliest branching symbiotic Frankia clade. A subfamily of a gene family encoding nodule-specific defensin-like cysteine-rich peptides is highly expressed in D. glomerata nodules. Phylogenetic analysis of the defensin domain showed that these defensin-like peptides share a common evolutionary origin with nodule-specific defensins from actinorhizal Fagales and with nodule-specific cysteine-rich peptides (NCRs) from legumes. In this study, the family member with the highest expression levels, DgDef1, was characterized. Promoter-GUS studies on transgenic hairy roots showed expression in the early stage of differentiation of infected cells, and transient expression in the nodule apex. DgDef1 contains an N-terminal signal peptide and a C-terminal acidic domain which are likely involved in subcellular targeting and do not affect peptide activity. In vitro studies with E. coli and Sinorhizobium meliloti 1021 showed that the defensin domain of DgDef1 has a cytotoxic effect, leading to membrane disruption with 50% lethality for S. meliloti 1021 at 20.8 μM. Analysis of the S. meliloti 1021 transcriptome showed that, at sublethal concentrations, DgDef1 induced the expression of terminal quinol oxidases, which are associated with the oxidative stress response and are also expressed during symbiosis. Overall, the changes induced by DgDef1 are reminiscent of those of some legume NCRs, suggesting that nodule-specific defensin-like peptides were part of the original root nodule toolkit and were subsequently lost in most symbiotic legumes, while being maintained in the actinorhizal lineages.
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Lundquist, Per-Olof, et Kerstin Huss-Danell. « Response of nitrogenase to altered carbon supply in a Frankia-Alnus incana symbiosis ». Physiologia Plantarum 83, no 3 (novembre 1991) : 331–38. http://dx.doi.org/10.1111/j.1399-3054.1991.tb00102.x.
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Valverde, Claudio, et Luis Gabriel Wall. « Regulation of nodulation in Discaria trinervis (Rhamnaceae) - Frankia symbiosis ». Canadian Journal of Botany 77, no 9 (1999) : 1302–10. http://dx.doi.org/10.1139/cjb-77-9-1302.
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