Artículos (Microbiología)

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A Complex Regulatory Network Governs the Expression of Symbiotic Genes in Sinorhizobium Fredii HH103
(Frontiers Media, 2023) Navarro Gómez, Pilar; Fuentes Romero, Francisco; Pérez Montaño, Francisco de Asís; Jiménez Guerrero, Irene; Alías Villegas, Cynthia; Ayala García, Paula; Almozara, Andrés; Medina Morillas, Carlos; Ollero Márquez, Francisco Javier; Rodríguez Carvajal, Miguel Ángel; Ruiz Sainz, José Enrique; López Baena, Francisco Javier; Vinardell González, José María; Acosta Jurado, Sebastián; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Química orgánica; Ministerio de Ciencia e Innovación (MICIN). España
Introduction: The establishment of the rhizobium-legume nitrogen-fixing symbiosis relies on the interchange of molecular signals between the two symbionts. We have previously studied by RNA-seq the effect of the symbiotic regulators NodD1, SyrM, and TtsI on the expression of the symbiotic genes (the nod regulon) of Sinorhizobium fredii HH103 upon treatment with the isoflavone genistein. In this work we have further investigated this regulatory network by incorporating new RNA-seq data of HH103 mutants in two other regulatory genes, nodD2 and nolR. Both genes code for global regulators with a predominant repressor effect on the nod regulon, although NodD2 acts as an activator of a small number of HH103 symbiotic genes. Methods: By combining RNA-seq data, qPCR experiments, and b-galactosidase assays of HH103 mutants harbouring a lacZ gene inserted into a regulatory gene, we have analysed the regulatory relations between the nodD1, nodD2, nolR, syrM, and ttsI genes, confirming previous data and discovering previously unknown relations. Results and discussion: Previously we showed that HH103 mutants in the nodD2, nolR, syrM, or ttsI genes gain effective nodulation with Lotus japonicus, a model legume, although with different symbiotic performances. Here we show that the combinations of mutations in these genes led, in most cases, to a decrease in symbiotic effectiveness, although all of them retained the ability to induce the formation of nitrogen-fixing nodules. In fact, the nodD2, nolR, and syrM single and double mutants share a set of Nod factors, either overproduced by them or not generated by the wild-type strain, that might be responsible for gaining effective nodulation with L. japonicus.
A transcriptomic analysis of the effect of genistein on Sinorhizobium fredii HH103 reveals novel rhizobial genes putatively involved in symbiosis
(Nature Publishing Group, 2016) Pérez Montaño, Francisco de Asís; Jiménez Guerrero, Irene; Acosta Jurado, Sebastián; Navarro Gómez, Pilar; Ollero Márquez, Francisco Javier; Ruiz Sainz, José Enrique; López Baena, Francisco Javier; Vinardell González, José María; Universidad de Sevilla. Departamento de Microbiología
Sinorhizobium fredii HH103 is a rhizobial soybean symbiont that exhibits an extremely broad host-range. Flavonoids exuded by legume roots induce the expression of rhizobial symbiotic genes and activate the bacterial protein NodD, which binds to regulatory DNA sequences called nod boxes (NB). NB drive the expression of genes involved in the production of molecular signals (Nod factors) as well as the transcription of ttsI, whose encoded product binds to tts boxes (TB), inducing the secretion of proteins (effectors) through the type 3 secretion system (T3SS). In this work, a S. fredii HH103 global gene expression analysis in the presence of the flavonoid genistein was carried out, revealing a complex regulatory network. Three groups of genes differentially expressed were identified: i) genes controlled by NB, ii) genes regulated by TB, and iii) genes not preceded by a NB or a TB. Interestingly, we have found differentially expressed genes not previously studied in rhizobia, being some of them not related to Nod factors or the T3SS. Future characterization of these putative symbiotic-related genes could shed light on the understanding of the complex molecular dialogue established between rhizobia and legumes.
Deciphering the Symbiotic Significance of Quorum Sensing Systems of Sinorhizobium fredii HH103
(MDPI, 2020) Acosta Jurado, Sebastián; Alías Villegas, Cynthia; Espuny Gómez, María del Rosario; Vinardell González, José María; Pérez Montaño, Francisco de Asís; Universidad de Sevilla. Departamento de Microbiología
Quorum sensing (QS) is a bacterial cell-to-cell signaling mechanism that collectively regulates and synchronizes behaviors by means of small diffusible chemical molecules. In rhizobia, QS systems usually relies on the synthesis and detection of N-acyl-homoserine lactones (AHLs). In the model bacterium Sinorhizobium meliloti functions regulated by the QS systems TraI-TraR and SinI-SinR(-ExpR) include plasmid transfer, production of surface polysaccharides, motility, growth rate and nodulation. These systems are also present in other bacteria of the Sinorhizobium genus, with variations at the species and strain level. In Sinorhizobium fredii NGR234 phenotypes regulated by QS are plasmid transfer, growth rate, sedimentation, motility, biofilm formation, EPS production and copy number of the symbiotic plasmid (pSym). The analysis of the S. fredii HH103 genomes reveal also the presence of both QS systems. In this manuscript we characterized the QS systems of S. fredii HH103, determining that both TraI and SinI AHL-synthases proteins are responsible of the production of short- and long-chain AHLs, respectively, at very low and not physiological concentrations. Interestingly, the main HH103 luxR-type genes, expR and traR, are split into two ORFs, suggesting that in S. fredii HH103 the corresponding carboxy-terminal proteins, which contain the DNA-binding motives, may control target genes in an AHL-independent manner. The presence of a split traR gene is common in other S. fredii strains.
Exopolysaccharide Production by Sinorhizobium fredii HH103 Is Repressed by Genistein in a NodD1-Dependent Manner
(Public Library of Science, 2016) Acosta Jurado, Sebastián; Navarro Gómez, Pilar; Murdoch, Piedad del Socorro; Crespo Rivas, Juan Carlos; Shi Jie; Cuesta Berrio, Lidia; Ruiz Sainz, José Enrique; Rodríguez Carvajal, Miguel Ángel; Vinardell González, José María; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Química orgánica; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía
In the rhizobia-legume symbiotic interaction, bacterial surface polysaccharides, such as exopolysaccharide (EPS), lipopolysaccharide (LPS), K-antigen polysaccharide (KPS) or cyclic glucans (CG), appear to play crucial roles either acting as signals required for the progression of the interaction and/or preventing host defence mechanisms. The symbiotic significance of each of these polysaccharides varies depending on the specific rhizobialegume couple. In this work we show that the production of exopolysaccharide by Sinorhizobium fredii HH103, but not by other S. fredii strains such as USDA257 or NGR234, is repressed by nod gene inducing flavonoids such as genistein and that this repression is dependent on the presence of a functional NodD1 protein. In agreement with the importance of EPS for bacterial biofilms, this reduced EPS production upon treatment with flavonoids correlates with decreased biofilm formation ability. By using quantitative RT-PCR analysis we show that expression of the exoY2 and exoK genes is repressed in late stationary cultures of S. fredii HH103 upon treatment with genistein. Results presented in this work show that in S. fredii HH103 EPS production is regulated just in the opposite way than other bacterial signals such as Nod factors and type 3 secreted effectors: it is repressed by flavonoids and NodD1 and enhanced by the nod repressor NolR. These results are in agreement with our previous observations showing that lack of EPS production by S. fredii HH103 is not only non-detrimental but even beneficial for symbiosis with soybean
Non-Ionic Osmotic Stress Induces the Biosynthesis of Nodulation Factors and Affects Other Symbiotic Traits in Sinorhizobium fredii HH103
(MDPI, 2023) Fuentes Romero, Francisco; Moyano Bravo, Isamar; Ayala García, Paula; Rodríguez Carvajal, Miguel Ángel; Pérez Montaño, Francisco de Asís; Acosta Jurado, Sebastián; Ollero Márquez, Francisco Javier; Vinardell González, José María; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Química orgánica; Ministerio de Ciencia, Innovación y Universidades (MICINN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla
Simple Summary: Rhizobia are soil proteobacteria able to establish nitrogen-fixing symbiosis with host legumes. This symbiotic interaction, which is highly important from ecological and agronomical points of view since it allows growth of legumes in soils poor in nitrogen, requires a complex interchange of molecular signals between both symbionts. The production of rhizobial molecular signals is elicited by flavonoids, which are phenolic compounds exuded by legume roots. Recent work has shown that osmotic stress can also promote the formation of symbiotic signals in some rhizobia. In this work, we show that this is also the case for Sinorhizobium fredii HH103, a rhizobial strain able to establish symbiosis with hundreds of legumes, including the very important crop, soybean. Non-ionic osmotic stress, which can be encountered by the bacterium in the rhizosphere or inside the legume host, affected the expression of hundreds of bacterial genes and, consequently, influenced diverse bacterial traits, including the production of symbiotic signals and certain characteristics that may be relevant for successful interaction with the host: motility, production of the phytohormone indole acetic acid, and production of molecules involved in bacterial cell-to-cell communication. Thus, our work provides new evidence of how stress can promote rhizobia-legume symbiosis. Abstract: (1) Background: Some rhizobia, such as Rhizobium tropici CIAT 899, activate nodulation genes when grown under osmotic stress. This work aims to determine whether this phenomenon also takes place in Sinorhizobium fredii HH103. (2) Methods: HH103 was grown with and without 400 mM mannitol. β-galactosidase assays, nodulation factor extraction, purification and identification by mass spectrometry, transcriptomics by RNA sequencing, motility assays, indole acetic acid quantification, analysis of acyl-homoserine lactones, and indole acetic acid quantification were performed. (3) Results: Non-ionic osmotic stress induced the production of nodulation factors. Fortytwo different factors were detected, compared to 14 found in the absence of mannitol. Transcriptomics indicated that hundreds of genes were either activated or repressed upon non-ionic osmotic stress. The presence of 400 mM mannitol induced the production of indole acetic acid and acyl homoserine lactones, abolished swimming, and promoted surface motility. (4) Conclusions: In this work, we show that non-ionic stress in S. fredii HH103, caused by growth in the presence of 400 mM mannitol, provokes notable changes not only in gene expression but also in various bacterial traits, including the production of nodulation factors and other symbiotic signals.
Rhizobial exopolysaccharides: Genetic regulation of their synthesis and relevance in symbiosis with legumes
(Multidisciplinary Digital Publishing Institute (MDPI), 2021) Acosta Jurado, Sebastián; Fuentes Romero, Francisco; Ruiz Sainz, José Enrique; Janczarek, Monika; Vinardell González, José María; Universidad de Sevilla. Departamento de Microbiología
Rhizobia are soil proteobacteria able to engage in a nitrogen‐fixing symbiotic interaction with legumes that involves the rhizobial infection of roots and the bacterial invasion of new organs formed by the plant in response to the presence of appropriate bacterial partners. This interaction relies on a complex molecular dialogue between both symbionts. Bacterial N‐acetyl‐glucosamine oligomers called Nod factors are indispensable in most cases for early steps of the symbiotic inter-action. In addition, different rhizobial surface polysaccharides, such as exopolysaccharides (EPS), may also be symbiotically relevant. EPS are acidic polysaccharides located out of the cell with little or no cell association that carry out important roles both in free‐life and in symbiosis. EPS production is very complexly modulated and, frequently, co‐regulated with Nod factors, but the type of co‐regulation varies depending on the rhizobial strain. Many studies point out a signalling role for EPS‐derived oligosaccharides in root infection and nodule invasion but, in certain symbiotic cou-ples, EPS can be dispensable for a successful interaction. In summary, the complex regulation of the production of rhizobial EPS varies in different rhizobia, and the relevance of this polysaccharide in symbiosis with legumes depends on the specific interacting couple.
Sinorhizobium fredii HH103 invades lotus burttii by crack entry in a nod factor- and surface polysaccharide-dependent manner
(American Phytopathological Society, 2016) Acosta Jurado, Sebastián; Rodríguez-Navarro, Dulce Nombre; Kawaharada, Yasuyuki; Perea, Juan Fernández; Gil Serrano, Antonio Miguel; Jin, Haojie; An, Qi; Rodríguez Carvajal, Miguel Ángel; Andersen, Stig Uggerhøj; Sandal, Niels Nørgaard; Stougaard, Jens; Vinardell González, José María; Ruiz Sainz, José Enrique; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Química orgánica
Sinorhizobium fredii HH103-Rifr, a broad host range rhizobial strain, induces nitrogen-fixing nodules in Lotus burttii but ineffective nodules in L. japonicus. Confocal microscopy studies showed that Mesorhizobium loti MAFF303099 and S. fredii HH103-Rifr invade L. burttii roots through infection threads or epidermal cracks, respectively. Infection threads in root hairs were not observed in L. burttii plants inoculated with S. fredii HH103-Rifr. A S. fredii HH103-Rifr nodA mutant failed to nodulate L. burttii, demonstrating that Nod factors are strictly necessary for this crack-entry mode, and a noeL mutant was also severely impaired in L. burttii nodulation, indicating that the presence of fucosyl residues in the Nod factor is symbiotically relevant. However, significant symbiotic impacts due to the absence of methylation or to acetylation of the fucosyl residue were not detected. In contrast S. fredii HH103-Rifr mutants showing lipopolysaccharide alterations had reduced symbiotic capacity, while mutants affected in production of either exopolysaccharides, capsular polysaccharides, or both were not impaired in nodulation. Mutants unable to produce cyclic glucans and purine or pyrimidine auxotrophic mutants formed ineffective nodules with L. burttii. Flagellin-dependent bacterial mobility was not required for crack infection, since HH103-Rifr fla mutants nodulated L. burttii. None of the S. fredii HH103-Rif r surface-polysaccharide mutants gained effective nodulation with L. japonicus.
Sinorhizobium fredii HH103 nolR and nodD2 mutants gain capacity for infection thread invasion of Lotus japonicus Gifu and Lotus burttii
(Willey, 2019-03-06) Acosta Jurado, Sebastián; Rodríguez-Navarro, Dulce Nombre; Kawaharada, Yasuyuki; Rodríguez Carvajal, Miguel Ángel; Gil Serrano, Antonio Miguel; Soria Díaz, María Eugenia; Pérez Montaño, Francisco de Asís; Fernández Perea, Juan; Niu, Yanbo; Alias Villegas, Cynthia; Universidad de Sevilla. Departamento de Microbiología; Junta de Andalucía. P07-CVI-07500
Sinorhizobium fredii HH103 RifR, a broad-host-range rhizobial strain, forms ineffective nodules with Lotus japonicus but induces nitrogen-fixing nodules in Lotus burttii roots that are infected by intercellular entry. Here we show that HH103 RifR nolR or nodD2 mutants gain the ability to induce infection thread formation and to form nitrogen-fixing nodules in L. japonicus Gifu. Microscopy studies showed that the mode of infection of L. burttii roots by the nodD2 and nolR mutants switched from intercellular entry to infection threads (ITs). In the presence of the isoflavone genistein, both mutants overproduced Nod-factors. Transcriptomic analyses showed that, in the presence of Lotus japonicus Gifu root exudates, genes related to Nod factors production were overexpressed in both mutants in comparison to HH103 RifR. Complementation of the nodD2 and nolR mutants provoked a decrease in Nod-factor production, the incapacity to form nitrogen-fixing nodules with L. japonicus Gifu and restored the intercellular way of infection in L. burttii. Thus, the capacity of S. fredii HH103 RifR nodD2 and nolR mutants to infect L. burttii and L. japonicus Gifu by ITs and fix nitrogen L. japonicus Gifu might be correlated with Nod-factor overproduction, although other bacterial symbiotic signals could also be involved
Sinorhizobium fredii HH103 RirA is required for oxidative stress resistance and efficient symbiosis with Soybean
(MDPI, 2019-02-12) Crespo Rivas, Juan Carlos; Navarro Gómez, Pilar; Alías Villegas, Cynthia; Moreno Onorato, Francisco Javier; Cubo Sánchez, María Teresa; Vinardell González, José María; Ruiz Sainz, José Enrique; Acosta Jurado, Sebastián; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Biología Celular
Members of Rhizobiaceae contain a homologue of the iron-responsive regulatory protein RirA. In different bacteria, RirA acts as a repressor of iron uptake systems under iron-replete conditions and contributes to ameliorate cell damage during oxidative stress. In Rhizobium leguminosarum and Sinorhizobium meliloti, mutations in rirA do not impair symbiotic nitrogen fixation. In this study, a rirA mutant of broad host range S. fredii HH103 has been constructed (SVQ780) and its free-living and symbiotic phenotypes evaluated. No production of siderophores could be detected in either the wild-type or SVQ780. The rirA mutant exhibited a growth advantage under iron-deficient conditions and hypersensitivity to hydrogen peroxide in iron-rich medium. Transcription of rirA in HH103 is subject to autoregulation and inactivation of the gene upregulates fbpA, a gene putatively involved in iron transport. The S. fredii rirA mutant was able to nodulate soybean plants, but symbiotic nitrogen fixation was impaired. Nodules induced by the mutant were poorly infected compared to those induced by the wild-type. Genetic complementation reversed the mutant’s hypersensitivity to H2O2, expression of fbpA, and symbiotic deficiency in soybean plants. This is the first report that demonstrates a role for RirA in the Rhizobium-legume symbiosis.
Sinorhizobium fredii Strains HH103 and NGR234 Form Nitrogen Fixing Nodules With Diverse Wild Soybeans (Glycine soja) From Central China but Are Ineffective on Northern China Accessions
(Frontiers Media, 2018) Temprano Vera, Francisco Jesús; Rodríguez Navarro, Dulce Nombre; Acosta Jurado, Sebastián; Navarro Gómez, Pilar; Buendía Clavería, Ana María; Moreno Onorato, Francisco Javier; López Baena, Francisco Javier; Ruiz Sainz, José Enrique; Vinardell González, José María; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Biología Celular; Junta de Andalucía; Ministerio de Economía y Competitividad (MINECO). España
Sinorhizobium fredii indigenous populations are prevalent in provinces of Central China whereas Bradyrhizobium species (Bradyrhizobium japonicum, B. diazoefficiens, B. elkanii, and others) are more abundant in northern and southern provinces. The symbiotic properties of different soybean rhizobia have been investigated with 40 different wild soybean (Glycine soja) accessions from China, Japan, Russia, and South Korea. Bradyrhizobial strains nodulated all the wild soybeans tested, albeit efficiency of nitrogen fixation varied considerably among accessions. The symbiotic capacity of S. fredii HH103 with wild soybeans from Central China was clearly better than with the accessions found elsewhere. S. fredii NGR234, the rhizobial strain showing the broadest host range ever described, also formed nitrogen-fixing nodules with different G. soja accessions from Central China. To our knowledge, this is the first report describing an effective symbiosis between S. fredii NGR234 and G. soja. Mobilization of the S. fredii HH103 symbiotic plasmid to a NGR234 pSym-cured derivative (strain NGR234C) yielded transconjugants that formed ineffective nodules with G. max cv. Williams 82 and G. soja accession CH4. By contrast, transfer of the symbiotic plasmid pNGR234a to a pSym-cured derivative of S. fredii USDA193 generated transconjugants that effectively nodulated G. soja accession CH4 but failed to nodulate with G. max cv. Williams 82. These results indicate that intra-specific transference of the S. fredii symbiotic plasmids generates new strains with unpredictable symbiotic properties, probably due to the occurrence of new combinations of symbiotic signals.
Sinorhizobium meliloti DnaJ Is Required for Surface Motility, Stress Tolerance, and for Efficient Nodulation and Symbiotic Nitrogen Fixation
(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Brito Santana, Paula; Duque Pedraza, Julián J.; Bernabéu Roda, Lydia M.; Carvia-Hermoso, Cristina; Cuéllar, Virginia; Fuentes Romero, Francisco; Acosta Jurado, Sebastián; Vinardell González, José María; Soto, María J.; Universidad de Sevilla. Departamento de Microbiología; Ministerio de Ciencia e Innovación (MICIN). España
Bacterial surface motility is a complex microbial trait that contributes to host colonization. However, the knowledge about regulatory mechanisms that control surface translocation in rhizobia and their role in the establishment of symbiosis with legumes is still limited. Recently, 2-tridecanone (2-TDC) was identified as an infochemical in bacteria that hampers microbial colonization of plants. In the alfalfa symbiont Sinorhizobium meliloti, 2-TDC promotes a mode of surface motility that is mostly independent of flagella. To understand the mechanism of action of 2-TDC in S. meliloti and unveil genes putatively involved in plant colonization, Tn5 transposants derived from a flagellaless strain that were impaired in 2-TDC-induced surface spreading were isolated and genetically characterized. In one of the mutants, the gene coding for the chaperone DnaJ was inactivated. Characterization of this transposant and newly obtained flagella-minus and flagella-plus dnaJ deletion mutants revealed that DnaJ is essential for surface translocation, while it plays a minor role in swimming motility. DnaJ loss-of-function reduces salt and oxidative stress tolerance in S. meliloti and hinders the establishment of efficient symbiosis by affecting nodule formation efficiency, cellular infection, and nitrogen fixation. Intriguingly, the lack of DnaJ causes more severe defects in a flagellaless background. This work highlights the role of DnaJ in the free-living and symbiotic lifestyles of S. meliloti.
Structure and biological roles of Sinorhizobium fredii HH103 exopolysaccharide
(Public Library of Science, 2014) Rodríguez Navarro, Dulce Nombre; Rodríguez Carvajal, Miguel Ángel; Acosta Jurado, Sebastián; Soto Misffut, María José; Margaret Oliver, Isabel María; Crespo Rivas, Juan Carlos; Sanjuan, Juan; Temprano Vera, Francisco Jesús; Gil Serrano, Antonio Miguel; Ruiz Sainz, José Enrique; Vinardell González, José María; Universidad de Sevilla. Departamento de Química orgánica; Universidad de Sevilla. Departamento de Microbiología
Here we report that the structure of the Sinorhizobium fredii HH103 exopolysaccharide (EPS) is composed of glucose, galactose, glucuronic acid, pyruvic acid, in the ratios 5:2:2:1 and is partially acetylated. A S. fredii HH103 exoA mutant (SVQ530), unable to produce EPS, not only forms nitrogen fixing nodules with soybean but also shows increased competitive capacity for nodule occupancy. Mutant SVQ530 is, however, less competitive to nodulate Vigna unguiculata. Biofilm formation was reduced in mutant SVQ530 but increased in an EPS overproducing mutant. Mutant SVQ530 was impaired in surface motility and showed higher osmosensitivity compared to its wild type strain in media containing 50 mM NaCl or 5% (w/v) sucrose. Neither S. fredii HH103 nor 41 other S. fredii strains were recognized by soybean lectin (SBL). S. fredii HH103 mutants affected in exopolysaccharides (EPS), lipopolysaccharides (LPS), cyclic glucans (CG) or capsular polysaccharides (KPS) were not significantly impaired in their soybean-root attachment capacity, suggesting that these surface polysaccharides might not be relevant in early attachment to soybean roots. These results also indicate that the molecular mechanisms involved in S. fredii attachment to soybean roots might be different to those operating in Bradyrhizobium japonicum.
Surface Motility Regulation of Sinorhizobium fredii HH103 by Plant Flavonoids and the NodD1, TtsI, NolR, and MucR1 Symbiotic Bacterial Regulators
(Multidisciplinary Digital Publishing Institute (MDPI), 2022) Alías Villegas, Cynthia; Fuentes Romero, Francisco; Cuéllar, Virginia; Navarro Gómez, Pilar; Soto, María J.; Vinardell González, José María; Acosta Jurado, Sebastián; Universidad de Sevilla. Departamento de Microbiología; Ministerio de Ciencia e Innovación (MICIN). España
Bacteria can spread on surfaces to colonize new environments and access more resources. Rhizobia, a group of α- and β-Proteobacteria, establish nitrogen-fixing symbioses with legumes that rely on a complex signal interchange between the partners. Flavonoids exuded by plant roots and the bacterial transcriptional activator NodD control the transcription of different rhizobial genes (the so-called nod regulon) and, together with additional bacterial regulatory proteins (such as TtsI, MucR or NolR), influence the production of different rhizobial molecular signals. In Sinorhizobium fredii HH103, flavonoids and NodD have a negative effect on exopolysaccharide production and biofilm production. Since biofilm formation and motility are often inversely regulated, we have analysed whether flavonoids may influence the translocation of S. fredii HH103 on surfaces. We show that the presence of nod gene-inducing flavonoids does not affect swimming but promotes a mode of surface translocation, which involves both flagella-dependent and -independent mechanisms. This surface motility is regulated in a flavonoid-NodD1-TtsI-dependent manner, relies on the assembly of the symbiotic type 3 secretion system (T3SS), and involves the participation of additional modulators of the nod regulon (NolR and MucR1). To our knowledge, this is the first evidence indicating the participation of T3SS in surface motility in a plant-interacting bacterium. Interestingly, flavonoids acting as nod-gene inducers also participate in the inverse regulation of surface motility and biofilm formation, which could contribute to a more efficient plant colonisation.
The nodD1 Gene of Sinorhizobium fredii HH103 Restores Nodulation Capacity on Bean in a Rhizobium tropici CIAT 899 nodD1/nodD2 Mutant, but the Secondary Symbiotic Regulators nolR, nodD2 or syrM Prevent HH103 to Nodulate with This Legume
(MDPI, 2022) Fuentes Romero, Francisco; Navarro Gómez, Pilar; Ayala García, Paula; Moyano Bravo, Isamar; López Baena, Francisco Javier; Pérez Montaño, Francisco de Asís; Ollero Márquez, Francisco Javier; Ollero Márquez, Francisco Javier; Acosta Jurado, Sebastián; Vinardell González, José María; Universidad de Sevilla. Departamento de Microbiología; Ministerio de Ciencia, Innovación y Universidades (MICINN). España
Rhizobial NodD proteins and appropriate flavonoids induce rhizobial nodulation gene expression. In this study, we show that the nodD1 gene of Sinorhizobium fredii HH103, but not the nodD2 gene, can restore the nodulation capacity of a double nodD1/nodD2 mutant of Rhizobium tropici CIAT 899 in bean plants (Phaseolus vulgaris). S. fredii HH103 only induces pseudonodules in beans. We have also studied whether the mutation of different symbiotic regulatory genes may affect the symbiotic interaction of HH103 with beans: ttsI (the positive regulator of the symbiotic type 3 protein secretion system), and nodD2, nolR and syrM (all of them controlling the level of Nod factor production). Inactivation of either nodD2, nolR or syrM, but not that of ttsI, affected positively the symbiotic behavior of HH103 with beans, leading to the formation of colonized nodules. Acetylene reduction assays showed certain levels of nitrogenase activity that were higher in the case of the nodD2 and nolR mutants. Similar results have been previously obtained by our group with the model legume Lotus japonicus. Hence, the results obtained in the present work confirm that repression of Nod factor production, provided by either NodD2, NolR or SyrM, prevents HH103 to effectively nodulate several putative host plants.
The Sinorhizobium fredii HH103 Lipopolysaccharide is not only relevant at early soybean nodulation stages but also for symbiosome stability in mature nodules
(2013) Fedorova, Elena; Buendía Clavería, Ana María; Rodríguez Navarro, Dulce Nombre; Ruiz Sainz, José Enrique; Vinardell González, José María; Rodríguez Carvajal, Miguel Ángel; Hidalgo Perea, Ángeles; Margaret Oliver, Isabel María; Acosta Jurado, Sebastián; Mercedes Luc; Universidad de Sevilla. Departamento de Microbiología; Universidad de Sevilla. Departamento de Química Orgánica; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular
The Sinorhizobium fredii HH103 type III secretion system effector NopC blocks nodulation with Lotus japonicus Gifu
(Oxford, 2020-06-26) Jiménez Guerrero, Irene; Acosta Jurado, Sebastián; Medina Morillas, Carlos; Ollero Márquez, Francisco Javier; Alias Villegas, Cynthia; Vinardell González, José María; Pérez Montaño, Francisco de Asís; López Baena, Francisco Javier; Universidad de Sevilla. Departamento de Microbiología; Junta de Andalucía. P11- CVI-7050 and P11-CVI-7500
Results GunA from S. fredii HH103 shows cellulase activity and is secreted through the T3SS in response to the inducer flavonoid genistein. Interestingly, at the beggining of the symbiotic process, GunA was partially responsible for the induction of the expression of the soybean GmPR1 gene, a gene used as a marker for plant defense responses. However, GunAwas also detected in soybean and cowpea developed nodules. Finally, nodulation assays indicate that GunA is beneficial for symbiosis with soybean but detrimental with cowpea. Conclusion Secretion of GunA through the S. fredii HH103 T3SS clearly and differentially impacts the symbiotic performance of this strain with soybean and cowpea. GunA, or its cellulase activity, is recognised by soybean root cells very early in the symbiotic process but, curiously, its secretion can also be detected in mature nodules. This suggests different symbiotic roles at different symbiotic stages that need to be further elucidated
Transcriptomic studies of the effect of nod gene-inducing molecules in rhizobia: Different weapons, one purpose
(Multidisciplinary Digital Publishing Institute (MDPI), 2018) Jiménez Guerrero, Irene; Acosta Jurado, Sebastián; Cerro Sánchez, Pablo del; Navarro Gómez, Pilar; López Baena, Francisco Javier; Ollero Márquez, Francisco Javier; Vinardell González, José María; Pérez Montaño, Francisco de Asís; Universidad de Sevilla. Departamento de Microbiología; Ministerio de Economía y Competitividad (MINECO). España
Simultaneous quantification of transcripts of the whole bacterial genome allows the analysis of the global transcriptional response under changing conditions. RNA-seq and microarrays are the most used techniques to measure these transcriptomic changes, and both complement each other in transcriptome profiling. In this review, we exhaustively compiled the symbiosis-related transcriptomic reports (microarrays and RNA sequencing) carried out hitherto in rhizobia. This review is specially focused on transcriptomic changes that takes place when five rhizobial species, Bradyrhizobium japonicum (=diazoefficiens) USDA 110, Rhizobium leguminosarum biovar viciae 3841, Rhizobium tropici CIAT 899, Sinorhizobium (=Ensifer) meliloti 1021 and S. fredii HH103, recognize inducing flavonoids, plant-exuded phenolic compounds that activate the biosynthesis and export of Nod factors (NF) in all analysed rhizobia. Interestingly, our global transcriptomic comparison also indicates that each rhizobial species possesses its own arsenal of molecular weapons accompanying the set of NF in order to establish a successful interaction with host legumes.

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Examinando Artículos (Microbiología) por Autor "Acosta Jurado, Sebastián"