Peh Production, Flagellum Synthesis, and Virulence Reduced in Erwinia carotovora subsp. carotovora by Mutation in a Homologue of cytR

Erwinia carotovora subsp. carotovora is a causal agent of soft-rot diseases in a wide variety of plants. Here, we have isolated a new regulatory factor involved in the virulence of E. carotovora subsp. carotovora by in vivo insertional mutagenesis using a transposon Tn5. The gene was homologous to cytR encoding a transcriptional repressor of nucleoside uptake and catabolism genes in Escherichia coli, Salmonella typhimurium, and Vibrio cholerae. Phenotypic characterization of a nonpolar deletion mutant of the cytR homologue (ΔcytR) revealed that the ΔcytR mutant produced a reduced level of polygalacturonase (Peh) and lost its motility compared to that in the parental strain. With electron microscopy, the ΔcytR mutant was shown to be aflagellate. Furthermore, the expression of fliA and fliC (encoding σ28 and flagellin, respectively) was also reduced in ΔcytR mutant. The virulence of ΔcytR mutant was reduced in Chinese cabbage and potato compared to that of the parental strain. These results suggest that the CytR homologue of E. carotovora subsp. carotovora positively controls Peh production and flagellum synthesis and plays an important role in its pathogenicity.

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Kemampuan Bakteri Endofit Akar dan Ubi Kentang untuk Menekan Penyakit Busuk Lunak (Erwinia carotovora pv. carotovora) pada Ubi

Agrikultura ◽

10.24198/agrikultura.v27i3.10880 ◽

2016 ◽

Vol 27 (3) ◽

Author(s):

Noor Istifadah ◽

Muhamad Salman Umar ◽

Sudarjat Sudarjat ◽

Luciana Djaya

Keyword(s):

Biological Control ◽

Potato Tuber ◽

Endophytic Bacteria ◽

Erwinia Carotovora ◽

Soft Rot ◽

Soft Rot Disease ◽

Post Harvest ◽

Rot Disease

ABSTRACTThe abilities of endophytic bacteria from potato roots and tubers to suppress soft rot disease (Erwinia carotovora pv. carotovora) in potato tuberSoft rot disease caused by Erwinia carotovora pv. carotovora is one of limiting factors in cultivation and post harvest of potato. The eco-friendly control measure that can be developed for controlling the diseases is biological control. Microbes that are potential as biological control agents include endophytic bacteria. This paper discussed the results of study examining the potential of endophytic bacteria isolated from roots and tubers of potato to inhibit the growth of E. carotovora pv. carotovora in vitro and suppress soft rot disease in potato tuber. The results showed that among 24 isolates examined, four isolates of endophytic bacteria (one isolate from potato tuber and three isolates from potato roots) inhibited the growth of E. carotovora pv. carotovora in vitro with inhibition zone 3.5-6.8 mm. In the in vivo test, the isolates inhibited the soft rot disease in potato tuber by 71.5-86.4%. The isolate that tended to show relatively better inhibition in vitro and in vivo was isolate from potato tuber which is CK U3 (Lysinibacillus sp.)Keywords: Biological control, Endophytic bacteria, Post-harvest, Potato, Soft rot diseaseABSTRAKPenyakit busuk lunak yang disebabkan bakteri Erwinia carotovora pv. carotovora, merupakan salah satu kendala dalam budidaya dan pascapanen kentang. Cara pengendalian ramah lingkungan yang dapat dikembangkan untuk menekan penyakit tersebut adalah pengendalian biologi. Kelompok mikroba yang berpotensi sebagi agens pengendali biologi adalah bakteri endofit. Artikel ini mendiskusikan potensi isolat bakteri endofit yang berasal dari ubi dan akar kentang untuk menghambat pertumbuhan bakteri E. carotovora pv. carotovora secara in vitro dan menekan perkembangan penyakit busuk lunak pada ubi kentang. Hasil percobaan menunjukkan bahwa diantara 24 isolat bakteri yang diuji, terdapat empat isolat bakteri endofit (satu isolat dari ubi kentang dan tiga isolat dari akar kentang) yang dapat menghambat pertumbuhan bakteri E. carotovora pv. carotovora secara in vitro dengan zona penghambatan sebesar 3,5-6,8 mm. Pada pengujian secara in vivo, isolat-isolat tersebut dapat menekan perkembangan penyakit busuk lunak pada ubi kentang sebesar 71,5-86,4%. Isolat yang cenderung menunjukkan penghambatan relatif lebih baik secara in vitro dan in vivo adalah isolat bakteri endofit asal ubi kentang yaitu isolat CK U3 (Lysinibacillus sp.).Kata Kunci: Pengendalian biologi, Bakteri endofit, Pascapanen, Kentang, Penyakit busuk basah

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Bacillus subtilis BS 107 as an antagonist of potato blackleg and soft rot bacteria

Canadian Journal of Microbiology ◽

10.1139/w98-064 ◽

1998 ◽

Vol 44 (8) ◽

pp. 777-783 ◽

Cited By ~ 12

Author(s):

B M Sharga ◽

G D Lyon

Keyword(s):

Bacillus Subtilis ◽

Erwinia Carotovora ◽

Soft Rot ◽

Defined Medium ◽

Alkaline Solutions ◽

Water Mixture ◽

Potato Blackleg ◽

Antimicrobial Substances

Antimicrobial substances were produced by Bacillus subtilis BS 107 in a defined medium and isolated from culture filtrate by precipitation at pH 2.5. Active fractions were extracted in ethyl acetate, acetone, and 80% ethanol and purified by thin-layer chromatography (TLC) on silica gel plates developed with an ethanol-water mixture (2:1, v/v). In each case, a band with a Rf of 0.75 formed an inhibitory zone when the TLC plates were placed in contact with agar seeded with test cultures of the Erwinia spp. The antibiotic was released into the culture medium during early stages of growth of Bacillus subtilis BS 107 but higher amounts were released in older cultures. The antibiotic was resistant to the action of nucleases, proteases, and lipase. It was stable when autoclaved twice for 35 min at 2 atm (1 atm = 101.325 kPa) in acidic, neutral, and alkaline solutions. It remained active over the pH range of 1-14 during 1 month of observation and exhibited no loss of antimicrobial activity when stored at 4°C for over 1 year. Bacillus subtilis BS 107 showed activity in vitro and in vivo against Erwinia carotovora subsp. atroseptica and Erwinia carotovora subsp. carotovora, the causal agents of potato blackleg and tuber soft rot. The application of an antagonist or its antibiotic to cut potato tissues prevented or reduced symptoms of the diseases. The antibiotic was active in vitro against a broad spectrum of bacterial and fungal species.Key words: antagonist, Bacillus subtilis BS 107, Erwinia carotovora, potato.

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Recovery of Fusarium oxysporum Fo47 Mutants Affected in Their Biocontrol Activity After Transposition of the Fot1 Element

Phytopathology ◽

10.1094/phyto.2002.92.9.936 ◽

2002 ◽

Vol 92 (9) ◽

pp. 936-945 ◽

Cited By ~ 19

Author(s):

Sophie Trouvelot ◽

Chantal Olivain ◽

Ghislaine Recorbet ◽

Quirico Migheli ◽

Claude Alabouvette

Keyword(s):

Fusarium Oxysporum ◽

Insertional Mutagenesis ◽

Wild Type Strain ◽

Growth Habit ◽

Antagonistic Activity ◽

Phenotypic Characterization ◽

Wild Type ◽

Biocontrol Activity

To investigate the biocontrol mechanisms by which the antagonistic Fusarium oxysporum strain Fo47 is active against Fusarium wilt, a Fot1 transposon-mediated insertional mutagenesis approach was adopted to generate mutants affected in their antagonistic activity. Ninety strains in which an active Fot1 copy had transposed were identified with a phenotypic assay for excision and tested for their biocontrol activity against F. oxysporum f. sp. lini on flax in greenhouse experiments. Sixteen strains were affected in their capacity to protect flax plants, either positively (more antagonistic than Fo47) or negatively (less antagonistic). The molecular characterization of these mutants confirms the excision of Fot1 and its reinsertion in most of the cases. Moreover, we demonstrate that other transposable elements such as Fot2, impala, and Hop have no transposition activity in the mutant genomes. The phenotypic characterization of these mutants shows that they are affected neither in their in vitro growth habit nor in their competitiveness in soil compared with wild-type strain Fo47. These results show that mutants are not impaired in their saprophytic phase and suggest that the altered biocontrol phenotype should likely be expressed during the interaction with the host plant.

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Isolation and Characterization of FecA- and FeoB-Mediated Iron Acquisition Systems of the Spirochete Leptospira biflexa by Random Insertional Mutagenesis

Journal of Bacteriology ◽

10.1128/jb.187.9.3249-3254.2005 ◽

2005 ◽

Vol 187 (9) ◽

pp. 3249-3254 ◽

Cited By ~ 45

Author(s):

Hélène Louvel ◽

Isabelle Saint Girons ◽

Mathieu Picardeau

Keyword(s):

Insertional Mutagenesis ◽

Iron Acquisition ◽

Transposon Mutagenesis ◽

Ecological Niches ◽

Acid Biosynthesis ◽

Gene Encoding ◽

Isolation And Characterization ◽

Transposon Mutants

ABSTRACT The specific mechanisms by which Leptospira spp. acquire iron from their ecological niches are unknown. A major factor contributing to our ignorance of spirochetal biology is the lack of methods for genetic analysis of these organisms. In this study, we have developed a system for random transposon mutagenesis of Leptospira biflexa using a mariner transposon, Himar1. To demonstrate the validity of Himar1 in vivo transposon mutagenesis in L. biflexa, a screen of mutants for clones impaired in amino acid biosynthesis was first performed, enabling the identification of tryptophan and glutamate auxotrophs. To investigate iron transporters, 2,000 L. biflexa transposon mutants were screened onto media with and without hemin, thus allowing the identification of five hemin-requiring mutants, and the putative genes responsible for this phenotype were identified. Three mutants had distinct insertions in a gene encoding a protein which shares homology with the TonB-dependent receptor FecA, involved in ferric citrate transport. We also identified two mutants with a Himar1 insertion into a feoB-like gene, the product of which is required for ferrous iron uptake in many bacterial organisms. Interestingly, the growth inhibition exhibited by the fecA and feoB mutants was relieved by deferoxamine, suggesting the presence of a ferric hydroxamate transporter. These results confirm the importance of iron for the growth of Leptospira and its ability to use multiple iron sources.

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Plant ferredoxin-like protein (PFLP) exhibits an anti-microbial ability against soft-rot pathogen Erwinia carotovora subsp. carotovora in vitro and in vivo

Plant Science ◽

10.1016/j.plantsci.2006.01.007 ◽

2006 ◽

Vol 171 (1) ◽

pp. 17-23 ◽

Cited By ~ 14

Author(s):

Hsiang-En Huang ◽

Mang-Jye Ger ◽

Chao-Ying Chen ◽

Mei-Kuen Yip ◽

Mei-Chu Chung ◽

...

Keyword(s):

Erwinia Carotovora ◽

Soft Rot

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Construction and Phenotypic Characterization of an Auxotrophic Mutant of Mycobacterium tuberculosis Defective in l-Arginine Biosynthesis

Infection and Immunity ◽

10.1128/iai.70.6.3080-3084.2002 ◽

2002 ◽

Vol 70 (6) ◽

pp. 3080-3084 ◽

Cited By ~ 55

Author(s):

Bhavna G. Gordhan ◽

Debbie A. Smith ◽

Heidi Alderton ◽

Ruth A. McAdam ◽

Gregory J. Bancroft ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Mutant Strain ◽

Auxotrophic Mutant ◽

Phenotypic Characterization ◽

Wild Type ◽

Arginine Biosynthesis ◽

High Concentrations

ABSTRACT A mutant of Mycobacterium tuberculosis defective in the metabolism of l-arginine was constructed by allelic exchange mutagenesis. The argF mutant strain required exogenous l-arginine for growth in vitro, and in the presence of 0.96 mM l-arginine, it achieved a growth rate and cell density in stationary phase comparable to those of the wild type. The mutant strain was also able to grow in the presence of high concentrations of argininosuccinate, but its auxotrophic phenotype could not be rescued by l-citrulline, suggesting that the ΔargF::hyg mutation exerted a polar effect on the downstream argG gene but not on argH. The mutant strain displayed reduced virulence in immunodeficient SCID mice and was highly attenuated in immunocompetent DBA/2 mice, suggesting that l-arginine availability is restricted in vivo.

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Genetic Interactions between the Coagulation and Fibrinolytic Systems

Thrombosis and Haemostasis ◽

10.1055/s-0037-1616209 ◽

2001 ◽

Vol 86 (07) ◽

pp. 130-137 ◽

Cited By ~ 13

Author(s):

Jay Degen

Keyword(s):

Associated Factors ◽

Genetic Interactions ◽

Phenotypic Characterization ◽

System Components ◽

Genes Encoding ◽

Hemostatic Factors ◽

Mouse Lines ◽

Made In

SummaryNearly all of the genes encoding the established coagulation and fibrinolytic factors have been successfully altered or disrupted in transgenic mice. Although comprehensive studies of each of these genetargeted mouse lines are still ongoing, the initial findings have significantly refined our understanding of the roles of selected hemostatic factors in vivo, and occasionally altered long-standing concepts. This review summarizes some of the progress that has been made in the generation and phenotypic characterization of mice lacking key hemostatic factors, including coagulation, fibrinolytic, platelet and endothelial cell-associated factors. New insights regarding the role(s) and interplay of hemostatic factors that have emerged from detailed studies of mice carrying multiple deficits in coagulation and fibrinolytic system components are highlighted.

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In vivo bone metastases, osteoclastogenic ability, and phenotypic characterization of human breast cancer cells

Bone ◽

10.1016/j.bone.2003.07.012 ◽

2004 ◽

Vol 34 (4) ◽

pp. 697-709 ◽

Cited By ~ 17

Author(s):

Nadia Rucci ◽

Enrico Ricevuto ◽

Corrado Ficorella ◽

Maurizio Longo ◽

Marie Perez ◽

...

Keyword(s):

Breast Cancer ◽

Bone Metastases ◽

Cancer Cells ◽

Human Breast Cancer ◽

Breast Cancer Cells ◽

Phenotypic Characterization ◽

Human Breast Cancer Cells ◽

Human Breast

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A homolog of human transcription factor NF-X1 encoded by the Drosophila shuttle craft gene is required in the embryonic central nervous system.

Molecular and Cellular Biology ◽

10.1128/mcb.16.1.192 ◽

1996 ◽

Vol 16 (1) ◽

pp. 192-201 ◽

Cited By ~ 27

Author(s):

N D Stroumbakis ◽

Z Li ◽

P P Tolias

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Transcription Factor ◽

Consensus Sequence ◽

Preliminary Evidence ◽

Phenotypic Characterization ◽

Binding Motif ◽

New Family

NF-X1 is a novel cytokine-inducible transcription factor that has been implicated in the control of immune responses in humans, presumably by regulating expression of class II major histocompatibility genes. Here we report the cloning and genetic characterization of the first reported NF-X1 homolog, which is encoded by the Drosophila melanogaster shuttle craft (stc) gene. The deduced sequence of the fly and human proteins defines a new family of molecules distinguished by a novel cysteine-rich DNA-binding motif (consisting of seven copies of the consensus sequence Cx3Cx3LxCGx0-5HxCx3CHxGxCx2Cx7-9CxC). We have identified and begun a phenotypic characterization of mutations in the stc gene. stc mutants die at the end of embryogenesis, when they appear to be incapable of coordinating the typical peristaltic contraction waves normally required for embryos to hatch into feeding first instar larvae. Preliminary evidence indicates that the resulting lethality of this behavioral defect is accompanied by subtle morphological abnormalities in the central nervous system, where in wild-type embryos, STC protein is normally localized in the nuclei of repeated cell clusters within each neuromere and brain lobe. Thus, the NF-X1 homolog encoded by the Drosophila stc gene defines a new family of putative transcription factors and plays an essential role in the completion of embryonic development. This study presents the first in vivo genetic analysis of a member of this new protein family.

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