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Marcella Holsters - One of the best experts on this subject based on the ideXlab platform.
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. A cDNA clone,
2015Co-Authors: Sofie Goormachtig, Sam Lievens, M Van Montagu, Willem Van De Velde, Marcella HolstersAbstract:On the tropical legume Sesbania rostrata, stem-borne nodules develop after inoculation of adventitious root primordia with the microsymbiont Azorhizobium caulinodan
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comparative transcriptome analysis reveals common and specific tags for root hair and crack entry invasion in sesbania rostrata
Plant Physiology, 2007Co-Authors: Ward Capoen, Jeroen Den Herder, Jeroen De Gussem, Annick De Keyser, Marcella Holsters, Stephane Rombauts, Sofie GoormachtigAbstract:The tropical legume Sesbania rostrata provides its microsymbiont Azorhizobium caulinodans with versatile invasion strategies to allow nodule formation in temporarily flooded habitats. In aerated soils, the bacteria enter via the root hair curling mechanism. Submergence prevents this epidermal invasion by accumulation of inhibiting concentrations of ethylene and, under these conditions, the bacterial colonization occurs via intercellular cortical infection at lateral root bases. The transcriptome of both invasion ways was compared by cDNA-amplified fragment length polymorphism analysis. Clusters of gene tags were identified that were specific for either epidermal or cortical invasion or were shared by both. The data provide insight into mechanisms that control infection and illustrate that entry via the epidermis adds a layer of complexity to rhizobial invasion.
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nodulation enhanced sequences from the water stress tolerant tropical legume sesbania rostrata
Plant Science, 2004Co-Authors: Katrien Schroeyers, Cristian Chaparro, Sofie Goormachtig, Marcella HolstersAbstract:The interaction of the tropical legume Sesbania rostrata with the Azorhizobium caulinodans bacterium results in the formation of nodules not only on roots but also on stems at adventitious root bases. Transcripts that are expressed during stem nodule initiation were identified with the suppression subtractive hybridization technique. Out of an original collection of 102, 26 genes were confirmed to be differentially expressed in macroarray hybridizations. Most of the genes belong to the medium-abundant expression group, but more information on some low-abundant differentially expressed genes was obtained by in situ hybridization. Two genes, SrSAMS and SrERF1 that are clearly enhanced during nodulation could be involved in the production and perception of ethylene, which is necessary for nodulation of S. rostrata under aquatic conditions.
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agrobacterium rhizogenes mediated transformation of sesbania rostrata
Plant Science, 2003Co-Authors: Willem Van De Velde, Joachim Mergeay, Marcella Holsters, Sofie GoormachtigAbstract:In order to study the function of nodulin genes and the activity of their promoters, the Agrobacterium rhizogenes transformation strategy was adopted for Sesbania rostrata. Two protocols were selected to generate S. rostrata transgenic roots that can be nodulated efficiently after application of Azorhizobium caulinodans, ORS571. Cotransformation frequencies of 22 and 72% were obtained with the first and second protocol, respectively. The transgenic root nodules showed no apparent differences when compared with the wild-type root nodules. The screening procedure for cotransformation of binary T-DNA in transgenic roots and root nodules was optimized by using an enhanced green-fluorescent protein construct. The A. rhizogenes transformation system was used to analyze the 35S promoter-driven expression of reporter genes in developing root nodules.
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pmh11 a tool for gene disruption and expression analysis in Azorhizobium caulinodans
Plasmid, 2002Co-Authors: Wim Dhaeze, Christa Verplancke, Vladimir Mironov, Marcella HolstersAbstract:Abstract Tools for mutagenesis and expression analyses are needed to study the role of bacterial genes. Here, we report the construction of pMH11, a small, mobilizable plasmid that replicates in Escherichia coli , but not in Azorhizobium caulinodans , a nodulating microsymbiont of Sesbania rostrata , and that contains a unique Bam HI restriction site upstream of a promoterless lacZ gene. pMH11 and two derivatives with the multiple cloning site of pBluescript (KS II ) are useful for mutagenesis by gene disruption and for expression analyses after selection for cointegration by kanamycin resistance. Weakly constitutive promoter activity from the vector allowed transcription of genes downstream of the integration site, so that no polar effects were caused by gene disruption.
Robert A. Ludwig - One of the best experts on this subject based on the ideXlab platform.
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respiratory membrane endo hydrogenase activity in the microaerophile Azorhizobium caulinodans is bidirectional
PLOS ONE, 2012Co-Authors: Brittany N Sprecher, Margo E Gittings, Robert A. LudwigAbstract:Background The microaerophilic bacterium Azorhizobium caulinodans, when fixing N2 both in pure cultures held at 20 µM dissolved O2 tension and as endosymbiont of Sesbania rostrata legume nodules, employs a novel, respiratory-membrane endo-hydrogenase to oxidize and recycle endogenous H2 produced by soluble Mo-dinitrogenase activity at the expense of O2.
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Azorhizobium caulinodans strains.
2012Co-Authors: Brittany N Sprecher, Margo E Gittings, Robert A. LudwigAbstract:Azorhizobium caulinodans strains.
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Respiratory Membrane endo-Hydrogenase Activity in the Microaerophile Azorhizobium caulinodans Is Bidirectional
2012Co-Authors: Brittany N Sprecher, Margo E Gittings, Robert A. LudwigAbstract:BackgroundThe microaerophilic bacterium Azorhizobium caulinodans, when fixing N2 both in pure cultures held at 20 µM dissolved O2 tension and as endosymbiont of Sesbania rostrata legume nodules, employs a novel, respiratory-membrane endo-hydrogenase to oxidize and recycle endogenous H2 produced by soluble Mo-dinitrogenase activity at the expense of O2. Methods and FindingsFrom a bioinformatic analysis, this endo-hydrogenase is a core (6 subunit) version of (14 subunit) NADH:ubiquinone oxidoreductase (respiratory complex I). In pure A. caulinodans liquid cultures, when O2 levels are lowered to
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personal correspondence
2003Co-Authors: John D. Scott, Robert A. LudwigAbstract:Azorhizobium caulinodans electron-transferring flavoprotein N electrochemically couples pyruvat
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Azorhizobium caulinodans respires with at least four terminal oxidases
Journal of Bacteriology, 1994Co-Authors: Christopher L. Kitts, Robert A. LudwigAbstract:Abstract In culture, Azorhizobium caulinodans used at least four terminal oxidases, cytochrome aa3 (cytaa3), cytd, cyto, and a second a-type cytochrome, which together mediated general, respiratory electron (e-) transport to O2. To genetically dissect physiological roles for these various terminal oxidases, corresponding Azorhizobium apocytochrome genes were cloned, and three cytaa3 mutants, a cytd mutant, and a cytaa3, cytd double mutant were constructed by reverse genetics. These cytochrome oxidase mutants were tested for growth, oxidase activities, and N2 fixation properties both in culture and in symbiosis with the host plant Sesbania rostrata. The cytaa3 mutants grew normally, fixed N2 normally, and remained fully able to oxidize general respiratory e- donors (NADH, succinate) which utilize a cytc-dependent oxidase. By difference spectroscopy, a second, a-type cytochrome was detected in the cytaa3 mutants. This alternative a-type cytochrome (Amax = 610 nm) was also present in the wild type but was masked by bona fide cytaa3 (Amax = 605 nm). In late exponential-phase cultures, the cytaa3 mutants induced a new, membrane-bound, CO-binding cytc550, which also might serve as a cytc oxidase (a fifth terminal oxidase). The cloned Azorhizobium cytaa3 genes were strongly expressed during exponential growth but were deactivated prior to onset of stationary phase. Azorhizobium cytd mutants showed 40% lower N2 fixation rates in culture and in planta, but aerobic growth rates were wild type. The cytaa3, cytd double mutant showed 70% lower N2 fixation rates in planta. Pleiotropic cytc mutants were isolated by screening for strains unable to use N,N,N',N'-tetramethyl-p-phenylenediamine as a respiratory e- donor. These mutants synthesized no detectable cytc, excreted coproporphyrin, grew normally in aerobic minimal medium, grew poorly in rich medium, and fixed N2 poorly both in culture and in planta. Therefore, while aerobic growth was sustained by quinol oxidases alone, N2 fixation required cytc oxidase activities. Assuming that the terminal oxidases function as do their homologs in other bacteria, Azorhizobium respiration simultaneously employs both quinol and cytc oxidases. Because Azorhizobium terminal oxidase mutants were able to reformulate their terminal oxidase mix and grow more or less normally in aerobic culture, these terminal oxidases are somewhat degenerate. Its extensive terminal oxidase repertoire might allow Azorhizobium spp. to flourish in wide-ranging O2 environments.
Sofie Goormachtig - One of the best experts on this subject based on the ideXlab platform.
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. A cDNA clone,
2015Co-Authors: Sofie Goormachtig, Sam Lievens, M Van Montagu, Willem Van De Velde, Marcella HolstersAbstract:On the tropical legume Sesbania rostrata, stem-borne nodules develop after inoculation of adventitious root primordia with the microsymbiont Azorhizobium caulinodan
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comparative transcriptome analysis reveals common and specific tags for root hair and crack entry invasion in sesbania rostrata
Plant Physiology, 2007Co-Authors: Ward Capoen, Jeroen Den Herder, Jeroen De Gussem, Annick De Keyser, Marcella Holsters, Stephane Rombauts, Sofie GoormachtigAbstract:The tropical legume Sesbania rostrata provides its microsymbiont Azorhizobium caulinodans with versatile invasion strategies to allow nodule formation in temporarily flooded habitats. In aerated soils, the bacteria enter via the root hair curling mechanism. Submergence prevents this epidermal invasion by accumulation of inhibiting concentrations of ethylene and, under these conditions, the bacterial colonization occurs via intercellular cortical infection at lateral root bases. The transcriptome of both invasion ways was compared by cDNA-amplified fragment length polymorphism analysis. Clusters of gene tags were identified that were specific for either epidermal or cortical invasion or were shared by both. The data provide insight into mechanisms that control infection and illustrate that entry via the epidermis adds a layer of complexity to rhizobial invasion.
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nodulation enhanced sequences from the water stress tolerant tropical legume sesbania rostrata
Plant Science, 2004Co-Authors: Katrien Schroeyers, Cristian Chaparro, Sofie Goormachtig, Marcella HolstersAbstract:The interaction of the tropical legume Sesbania rostrata with the Azorhizobium caulinodans bacterium results in the formation of nodules not only on roots but also on stems at adventitious root bases. Transcripts that are expressed during stem nodule initiation were identified with the suppression subtractive hybridization technique. Out of an original collection of 102, 26 genes were confirmed to be differentially expressed in macroarray hybridizations. Most of the genes belong to the medium-abundant expression group, but more information on some low-abundant differentially expressed genes was obtained by in situ hybridization. Two genes, SrSAMS and SrERF1 that are clearly enhanced during nodulation could be involved in the production and perception of ethylene, which is necessary for nodulation of S. rostrata under aquatic conditions.
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agrobacterium rhizogenes mediated transformation of sesbania rostrata
Plant Science, 2003Co-Authors: Willem Van De Velde, Joachim Mergeay, Marcella Holsters, Sofie GoormachtigAbstract:In order to study the function of nodulin genes and the activity of their promoters, the Agrobacterium rhizogenes transformation strategy was adopted for Sesbania rostrata. Two protocols were selected to generate S. rostrata transgenic roots that can be nodulated efficiently after application of Azorhizobium caulinodans, ORS571. Cotransformation frequencies of 22 and 72% were obtained with the first and second protocol, respectively. The transgenic root nodules showed no apparent differences when compared with the wild-type root nodules. The screening procedure for cotransformation of binary T-DNA in transgenic roots and root nodules was optimized by using an enhanced green-fluorescent protein construct. The A. rhizogenes transformation system was used to analyze the 35S promoter-driven expression of reporter genes in developing root nodules.
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patterns of pectin methylesterase transcripts in developing stem nodules of sesbania rostrata
Molecular Plant-microbe Interactions, 2002Co-Authors: Sam Lievens, Sylvia Herman, Sofie Goormachtig, Marcella HolstersAbstract:Differential display was applied to the early stages of the interaction between the tropical legume Sesbania rostrata and its microsymbiont Azorhizobium caulinodans ORS571. An upregulated clone that is similar to pectin methylesterase-encoding genes was isolated (Srpmel). The full-length sequence of Srpmel was used to localize PME transcripts in situ during S. rostrata stem-nodule development. Several expression patterns were distinguished, hinting at general roles in vascular tissue development and cell division or expansion and at symbiosis-specific functions, such as uninfected cell differentiation.
Edward C. Cocking - One of the best experts on this subject based on the ideXlab platform.
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Xylem Colonization of Tomato by Azorhizobium Caulinodans ORS571
Acta Biologica Hungarica, 2001Co-Authors: Edward C. CockingAbstract:Tomato seedlings growing aseptically in Murashige and Skoog Medium were inoculated with Azorhizobium caulinodans ORS571 (pXLGD4), carrying the lacZ reporter gene. By microscopic analyses of inoculated tomato roots, it has been demonstrated that the xylem of tomato roots can be colonized by Azorhizobium . We discuss whether this colonization of the xylem of tomato roots by diazotrophic azorhizobia might provide a suitable niche for endophytic nitrogen fixation.
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Azorhizobium caulinodans ors571 colonizes the xylem of arabidopsis thaliana
Molecular Plant-microbe Interactions, 2001Co-Authors: Philip J Stone, K J Ocallaghan, M. R. Davey, Edward C. CockingAbstract:Improved conditions were used for the aseptic growth of Arabidopsis thaliana to investigate whether xylem colonization of A. thaliana by Azorhizobium caulinodans ORS571 might occur. When seedlings were inoculated with ORS571 (pXLGD4) tagged with the lacZ reporter gene, nearly all of the plants showed blue regions of ORS571 colonization at lateral root cracks (LRC). The flavonoids naringenin and liquiritigenin significantly stimulated colonization of LRC by ORS571. Blue bands of ORS571 (pXLGD4) bacteria were observed histochemically in the xylem of intact roots of inoculated plants. Detailed microscopic analysis of sections of primary and lateral roots from inoculated A. thaliana confirmed xylem colonization. Xylem colonization also occurred with an ORS571 nodC mutant deficient in nodulation factors. There was no significant difference in the percentage of plants with xylem colonization or in the mean length of xylem colonized per plant between plants inoculated with either ORS571 (pXLGD4) or ORS571::nodC (pXLGD4), with or without naringenin.
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The xylem of rice ( Oryza sativa ) is colonized by Azorhizobium caulinodans
Proceedings of The Royal Society B: Biological Sciences, 2000Co-Authors: Ganesan Gopalaswamy, K. J. O’callaghan, Michael R. Davey, Sadasivam Kannaiyan, Edward C. CockingAbstract:Following inoculation with Azorhizobium caulinodans ORS571(pXLGD4), lateral root development of rice and colonization of lateral root cracks by bacteria were shown to be stimulated by the flavonoid naringenin. Rice seedlings growing aseptically in the presence of naringenin were inoculated with ORS571(pXLGD4), carrying the lac Z reporter gene. By microscopic analysis of sections of inoculated rice roots, it has been demonstrated that the xylem of rice roots can be colonized by Azorhizobium caulinodans . We discuss whether this colonization of the xylem of rice roots by azorhizobia could provide a suitable niche for endophytic nitrogen fixation.
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xylem colonization of sesbania rostrata by Azorhizobium caulinodans ors571
Highlights of nitrogen fixation research. Proceedings of the Sixteenth North American Conference on Symbiotic Nitrogen Fixation held in Cancun Mexico , 1999Co-Authors: K J Ocallaghan, M. R. Davey, Edward C. CockingAbstract:Benign, non-rhizobial, endophytic bacteria probably exist in the xylem of many healthy plants (Bell et al., 1995; Kloepper et al., 1992), including legumes (Gagne et al., 1987). Agrobacteria, plant pathogens related closely to Rhizobium (Young, 1992), can move through the xylem of the legume Sesbania rostrata (Vlachova et al., 1987). The present study assessed the endophytic behaviour of Azorhizobium caulinodans ORS571, in non-nodular tissues of its host, S. rostrata. ORS571 colonized xylem elements, in addition to invading the nodules of this plant.
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Crack Entry Invasion of Sesbania rostrata by Azorhizobium caulinodans ORS571 is Nod Gene-Independent
Biological Nitrogen Fixation for the 21st Century, 1998Co-Authors: K. J. O’callaghan, M. R. Davey, Edward C. CockingAbstract:After activation of rhizobial nodABC genes, rhizobia release Nod factors which induce nodule meristems in the plant host. The nodABC genes play an essential role in the early stages of invasion by Rhizobium meliloti, which invades alfalfa via the root hair curling pathway (Denarie et al. 1992). Azorhizobium caulinodans ORS571 contains genes showing some homology to the nodABC genes of R. meliloti (Goethals et al. 1989), but invades its host, the tropical legume Sesbania rostrata, by entering the naturally occurring cracks which form around emergent lateral roots. The significance of the fact that rhizobial invasion pathways differ so greatly is unclear.
Toshihiro Aono - One of the best experts on this subject based on the ideXlab platform.
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intercellular and intracellular colonization of Azorhizobium caulinodans in arabidopsis thaliana under nitrogen deficient conditions
Soil Science and Plant Nutrition, 2021Co-Authors: Keigo Kurumisawa, Junichi Matsuoka, Fumiko Ishizuna, Tetsuhiro Ogawa, Kengo Morohashi, Toshihiro AonoAbstract:Azorhizobium caulinodans ORS571 is a microsymbiont of the tropical legume Sesbania rostrata. This bacterium induces nodules on the stems and roots of host plants, and fixes nitrogen in the host cel...
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lysr type transcriptional regulator of high temperature inducible class a β lactamase gene controls pathogenic r body production genes in Azorhizobium caulinodans
Soil Science and Plant Nutrition, 2021Co-Authors: Tomoki Hirakawa, Junichi Matsuoka, Tetsuhiro Ogawa, Makoto Hidaka, Kengo Morohashi, Toshihiro AonoAbstract:Azorhizobium caulinodans ORS571 is a rhizobium of the tropical legume Sesbania rostrata. This bacterium possesses the reb operon, which is associated with pathogenic R-bodies. To establish symbiosi...
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localization of the reb operon expression is inconsistent with that of the r body production in the stem nodules formed by Azorhizobium caulinodans mutants having a deletion of prar
Journal of General and Applied Microbiology, 2019Co-Authors: Junichi Matsuoka, Fumiko Ishizuna, Tetsuhiro Ogawa, Makoto Hidaka, Lowela Siarot, Toshihiro AonoAbstract:Azorhizobium caulinodans, a kind of rhizobia, has a reb operon encoding pathogenic R-body components, whose expression is usually repressed by a transcription factor PraR. Mutation on praR induced a high expression of reb operon and the formation of aberrant nodules, in which both morphologically normal and shrunken host cells were observed. Histochemical GUS analyses of praR mutant expressing reb operon-uidA fusion revealed that the bacterial cells within the normal host cells highly expressed the reb operon, but rarely produced R-bodies. On the other hand, the bacterial cells within the shrunken host cells frequently produced R-bodies but rarely expressed the reb operon. This suggests that R-body production is not only regulated at the transcriptional level, but by other regulatory mechanisms as well.
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a putative tetr type transcription factor azc_3265 from the legume symbiont Azorhizobium caulinodans represses the production of r bodies that are toxic to eukaryotic cells
Soil Science and Plant Nutrition, 2017Co-Authors: Jun Matsuoka, Fumiko Ishizuna, Tetsuhiro Ogawa, Makoto Hidaka, Keigo Kurumisawa, Kengo Morohashi, Katsuharu Saito, Tatsuhiro Ezawa, Toshihiro AonoAbstract:Azorhizobium caulinodans ORS571 is a microsymbiont of the legume Sesbania rostrata, which forms nitrogen-fixing nodules on stems and roots. This bacterium harbors a reb operon, which is associated ...
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an outer membrane autotransporter aoaa of Azorhizobium caulinodans is required for sustaining high n2 fixing activity of stem nodules
Fems Microbiology Letters, 2008Co-Authors: Tadahiro Suzuki, Toshihiro Aono, Chite Liu, Shino Suzuki, Taichiro Iki, Keisuke Yokota, Hiroshi OyaizuAbstract:In this study, we investigated the function of a putative high-molecular-weight outer membrane protein, azorhizobial outer membrane autotransporter A (AoaA), of Azorhizobium caulinodans ORS571. Sequence analysis revealed that AoaA was an autotransporter protein belonging to the type V protein secretion system. Azorhizobium caulinodans forms N2-fixing nodules on the stems and roots of Sesbania rostrata . The sizes of stem nodules formed by an aoaA mutant having transposon insertion within this ORF were as large as those in the wild-type strain, but the N2-fixing activity of the nodules by the aoaA mutant was lower than that of wild-type nodules. cDNA-amplified fragment length polymorphism and reverse transcriptase-PCR analysis revealed that the expressions of several pathogen-related genes of host plants were induced in the aoaA mutant nodules. Furthermore, exopolysaccharide production was defective in the aoaA mutant under free-living conditions. These results indicate that AoaA may have an important role in sustaining the symbiosis by suppressing plant defense responses. The exopolysaccharide production controlled by AoaA might mediate this suppression mechanism.
