Extracellular Enzymes and Pathogenesis of Soft-Rot Erwinia

Barras, Frédéric; Gijsegem, Frédérique Van; Chatterjee, Asita

doi:10.1146/annurev.py.32.090194.001221

Cited by 490 publications

(376 citation statements)

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“…E. carotovora species induce the soft rotting of many fruits and potatoes through the production of a battery of pectinolytic enzymes (Barras et al, 1994). Recently, we identified a strain of Erwinia carotovora carotovora, Ecc15, that-unlike most bacterial species-induced a systemic immune response in Drosophila larvae after natural ingestion (Basset et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

A single gene that promotes interaction of a phytopathogenic bacterium with its insect vector, Drosophila melanogaster

et al. 2003

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Insects are major vectors of plant and animal disease, and bacterial phytopathogens are often disseminated by flies. We have previously reported that some isolates of the phytopathogenic bacterial species Erwinia carotovora infect Drosophila and activate an immune response. Using a genetic screen, we have now identified two genes that are required by E. carotovora to infect Drosophila. One of these genes has a regulatory role whereas the other, evf, confers an infectious phenotype: its transfer to non-infectious Erwinia strains or to several enterobacteria improves survival in the gut and triggers the immune response. Overexpression of Erwinia virulence factor (evf) allowed bacteria to colonize the apical side of the gut epithelium and in some cases to spread to the body cavity. Our results demonstrate a specific interaction between plant pathogens and flies that promote their dissemination.

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Section: Introductionmentioning

confidence: 99%

A single gene that promotes interaction of a phytopathogenic bacterium with its insect vector, Drosophila melanogaster

et al. 2003

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“…A number of regulatory genes have been identified in Erwinia that specifically control the production of extracellular enzymes (Barras et al, 1994;Collmer & Keen, 1986;Kotoujansky, 1987), polysaccharides (Leigh & Coplin, 1992;Roberts & Coleman, 1991) and antibiotics (McGowan etal., 1995). Such specific regulatory systems are generally activated during lateexponential growth or early-stationary phase when bacAbbreviations: EPS, extracellular polysaccharide; HR, hypersensitive reaction; HSL, N-(3-oxohexanoyl)-~-homoserine lactone.…”

Section: Introductionmentioning

confidence: 99%

Global regulation in Erwinia species by Erwinia carotovora rsmA, a homologue of Escherichia coli csrA: repression of secondary metabolites, pathogenicity and hypersensitive reaction

et al. 1996

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Our previous studies revealed that rsmA of Erwinia carotovora subsp. carotovora strain 71 suppressed the synthesis of the cell density (quorum) sensing signal N-(3-oxohexanoyl)-~-homoserine lactone, the production of extracellular enzymes and tissue macerating ability in soft-rotting Erwinia species and that homologues of this negative regulator gene were present in other Erwinia species. Northern blot data presented here demonstrate that rsmA and rsmA-like genes are also expressed in soft-rotting and non-softrotting Erwinia spp. such as E. amylovora, E. carotovora subsp. atroseptica, E. carotovora subsp. betavasculorum, E. cerotovora subsp. carotovora, E. chrysanthemi, E. henbicola and E. stewaflii. A low-copy plasmid carrying rsmA of E. carotovora subsp. carotovora strain 71 caused suppression of antibiotic production in E. carotovora subsp. betavasculorum, flagellum formation in E. carotovora subsp. carotovora, carotenoid production in E. henbicola and E. stewartii, and indigoidine production in E. chrysanthemi. In E. amylovora, rsmA of E. carotovora subsp. carotovora suppressed the elicitation of the hypersensitive reaction in tobacco leaves and the production of disease symptoms in apple shoots, in addition to repressing motility and extracellular polysaccharide production. We conclude that rsmA homologues function as global regulators of secondary metabolic pathways as well as factors controlling host interaction of Entvinia species.

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“…These enzymes facilitate the maceration of host plant tissues and the liberation of nutrients. The aepA gene product is believed to regulate the timely induction of these exoenzymes by responding to levels of specific components of plant extracts to ensure optimal destruction of plant tissues before initiation of the host's defense response (Barras et al, 1994). The homology of LAF3 with this regulatory gene product is consistent with its role in coordinated induction and repression of several phyA-regulated mRNAs (Fig.…”

Section: Laf3 Appears To Be An Ortholog Of a Ubiquitous Bacterial Promentioning

confidence: 85%

“…1B) argues against a role restricted to regulation cell elongation. It is proposed that coordinated activation of the aepABH (activator of extracellular protein production) operon down-regulates expression of the rsmA repressor of the synthesis of cell walldegrading enzymes (Barras et al, 1994), although the precise role of aepA action in this process does not appear to have elucidated. Certainly, the ubiquitous presence of aepA and rsmA homologs throughout microbial kingdoms but not in animals suggests that their roles might extend beyond mediating pathogenicity.…”

Section: Laf3 Appears To Be An Ortholog Of a Ubiquitous Bacterial Promentioning

confidence: 99%

LAF3, a Novel Factor Required for Normal Phytochrome A Signaling

et al. 2003

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Phytochrome A (phyA) is the photolabile plant light receptor that mediates broad spectrum very low-fluence responses and high irradiance responses to continuous far-red light (FR c ). An Arabidopsis mutant laf3-1 (long after far-red 3) was recovered from a screen for transposon-tagged mutants that exhibit reduced inhibition of hypocotyl elongation in FR c . The laf phenotype correlated well with a strongly attenuated disappearance of XTR7 transcript in FR c . The effects of laf3-1 on phyA-controlled CAB, CHS, and PET H expression were more subtle, and the mutation had no clear effects on PET E and ASN1 transcript levels in FR c . The use of two alternative transcription initiation sites in the LAF3 gene generates two isoforms that differ only at their N termini. Transcripts encoding both isoforms were induced during germination and were present at slightly higher levels in de-etiolated seedlings than in those grown in darkness. No significant differential regulation of the two isoforms was observed upon exposure to either FR c or continuous red light. Transcripts encoding the shorter isoform (LAF3 ISF2 ) always appear to be more abundant than those encoding the longer isoform (LAF3 ISF1 ). However, both isoforms were capable of full complementation of the laf3-1 hypocotyl phenotype in FR c . When fused to a yellow fluorescent protein, both isoforms localize to the perinuclear region, suggesting that LAF3 encodes a product that might regulate nucleo-cytoplasmic trafficking of an intermediate(s) involved in phyA signal transduction.Phytochromes are soluble chromoproteins that regulate plant growth and development by their ability to interconvert between two stable spectral forms. Red light (R) converts the R-absorbing Pr form (the form synthesized in darkness) to the Pfr (far-red absorbing form) and far-red light (FR) reconverts Pfr to Pr. Two important features distinguish phytochrome A (phyA) from the other four phytochromes in Arabidopsis. First, although the Arabidopsis phytochromes phyB to phyE are activated exclusively by R and inactivated by irradiation with FR, phyA can be activated by FR and low fluences of R and blue light (B). Secondly, although phyA levels decrease rapidly after exposure to light as a result of both down-regulation of PHYA gene transcription (Cantó n and Quail, 1999) and far greater photolability of phyA than other phytochromes (Sharrock and Clack, 2002), phyA is by far the most abundant phytochrome in etiolated seedlings. These features enable phyA to perform a seminal role in triggering the shift between skotomorphogenesis and photomorphogenesis. Together, they ensure that the inhibition of hypocotyl elongation, and the activation of physiological changes needed to ensure photosynthetic competence are already underway when seedlings emerge from the soil surface. Despite its lability in light-grown plants, the influence of phyA throughout the life cycle is evidenced by its involvement in sensing photoperiod to ensure that flowering is initiated at the proper time (Johnson et al., 199...

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Extracellular Enzymes and Pathogenesis of Soft-Rot Erwinia

Cited by 490 publications

References 75 publications

A single gene that promotes interaction of a phytopathogenic bacterium with its insect vector, Drosophila melanogaster

A single gene that promotes interaction of a phytopathogenic bacterium with its insect vector, Drosophila melanogaster

Global regulation in Erwinia species by Erwinia carotovora rsmA, a homologue of Escherichia coli csrA: repression of secondary metabolites, pathogenicity and hypersensitive reaction

LAF3, a Novel Factor Required for Normal Phytochrome A Signaling

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