Pectate Lyase Regulation and Bacterial Soft-Rot Pathogenesis

Collmer, Alan; Berman, Phyllis; Mount, Mark S.

doi:10.1016/b978-0-12-509001-8.50027-5

Cited by 47 publications

(32 citation statements)

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“…Previous studies indicate that E. chrysanthemi extracellular enzymes are also regulated by growth phase (7,20). In contrast to previous work which suggested that expression of Mu-lac out insertion mutants in E. chrysanthemi 3937 is independent of growth phase (22), our results indicate that out gene regulation by growth phase parallels the regulation of E. chrysanthemi extracellular enzymes (Fig.…”

Section: Discussioncontrasting

confidence: 56%

“…In P. aeruginosa, in which the PulO homolog has been demonstrated to play a role in both pilin formation and protein secretion, it also appears to be transcribed independently of the pulE through pulM homologs (5). (7,9). However, the high level of pectate lyase induction observed here suggests that sufficient exo-poly-a-D-galacturonosidase escapes from these out mutants to initiate the induction process.…”

Section: Discussionmentioning

confidence: 99%

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Analysis of eight out genes in a cluster required for pectic enzyme secretion by Erwinia chrysanthemi: sequence comparison with secretion genes from other gram-negative bacteria

1992

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Many extraceliular proteins produced by Erwinia chrysanthemi require the out gene products for transport across the outer membrane. In a previous report (S. Y. He, M. Lindeberg, A. K. Chatterjee, and A. Collmer, Proc. Natl. Acad. Sci. USA 88:1079-1083, 1991) cosmid pCPP2006, sufficient for secretion of Erwinia chrysanthemi extracellular proteins by Escherichia coli, was partially sequenced, revealing four out genes sharing high homology with pulH through pulK from KiebsieUla oxytoca. The nucleotide sequence of eight additional out genes reveals homology with pulC through puiG, pulL, pulM, pulO, and other genes involved in secretion by various gram-negative bacteria. Although signal sequences and hydrophobic regions are generally conserved between Pul and Out proteins, four out genes contain unique inserts, a pulN homolog is not present, and outO appears to be transcribed separately from outC through outM. The sequenced region was subcloned, and an additional 7.6-kb region upstream was identified as being required for secretion in E. coli. out gene homologs were found on Erwinia carotovora cosmid clone pAKC651 but were not detected in E. coli. The outC-through-outM operon is weakly induced by polygalacturonic acid and strongly expressed in the early stationary phase. The out and pul genes are highly similar in sequence, hydropathic properties, and overall arrangement but differ in both transcriptional organization and the nature of their induction.Gram-negative bacteria employ several routes for the secretion of extracellular proteins (29). Among these, the Sec-dependent pathway appears to secrete the largest and most diverse group of proteins. This two-step pathway uses the Sec machinery for translocation across the inner membrane and an accessory secretion apparatus for translocation across the outer membrane. Secretion of the starch-degrading enzyme pullulanase by Kiebsiella oxytoca is the beststudied example of the Sec-dependent route (34). Pugsley and coworkers have demonstrated that pulS and a 13-gene operon (pulC throughpulO) are necessary and sufficient for secretion of the pullulanase enzyme across the outer membrane (34). Subsequent research has demonstrated that components of this secretion pathway are conserved among diverse gram-negative bacteria (29).Erwinia chrysanthemi and Erwinia carotovora, like many other bacterial pathogens of plants and animals, depend on extracellular proteins for virulence. Both of the Erwinia species secrete a wide variety of cell wall-degrading enzymes that macerate plant tissues and produce soft rot symptoms (27). Murata et al. (31) reported the cloning of a cluster of E. carotovora out genes that complemented all secretion mutants in that species. However, unlike the K oxytoca pulS-pulC-through-pulO secretion cluster, which enables Escherichia coli to secrete pullulanase, the E. carotovora out cluster does not confer on E. coli the ability to secrete E. carotovora pectic enzymes.The only other secretion genes known to confer on E. coli the ability to secrete heterologou...

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Section: Discussioncontrasting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Analysis of eight out genes in a cluster required for pectic enzyme secretion by Erwinia chrysanthemi: sequence comparison with secretion genes from other gram-negative bacteria

1992

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“…Hypothetically, in EC14, coordinate regulation would allow the endo-polygalacturonase to degrade plant cell wall pectic polymers to soluble oligogalacturonic acids. In turn, the intracellular exo-pectate lyase PDII would reduce these oligosaccharides to 4,5-unsaturated di-and trigalacturonic acids (5,18), Unsaturated digalacturonic acids may act as inducers of endo-pectate lyase in E. carotovora subsp. carotovora (P. M. Berman and M. S. Mount, unpublished observations), as well as in E. chrysanthemi (4).…”

Section: Downloaded Frommentioning

confidence: 99%

Requirement for two or more Erwinia carotovora subsp. carotovora pectolytic gene products for maceration of potato tuber tissue by Escherichia coli

Roberts¹,

Berman²,

Allen³

et al. 1986

J Bacteriol

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Several genes encoding enzymes capable of degrading plant cell wail components have been cloned from Erwinia carotovora subsp. carotovora EC14. Plasmids containing cloned EC14 DNA mediate the production of endo-pectate lyases, exo-pectate lyase, endo-polygalacturonase, and cellulase(s). Escherichua coil strains containing one of these plasmids or combinations of two plasmids were tested for their ability to macerate potato tuber slices. Only one E. coli strain, containing two plasnids that encode endo-pectate lyases, exo-pectate lyase, and endo-polygalacturonase, caused limited maceration. The pectolytic proteins associated with one of these plasmids, pDRI, have been described previously (D. P. Roberts, P. M. Berman, C. Allen, V. K. Stromberg, G. H. Lacy, and M. S. Mount, Can. J. Plant Pathol. 8:17-27, 1986) and include two secreted endo-pectate lyases. The second plasmid, pDR30, contains a 2.1-kiloabse EC14 DNA insert that mediates the production of an exo-pectate lyase and an endo-polygalacturonase. These enzymes are similar in physicochemical properties to those produced by EC14. Our results suggest that the concerted activities of endo-pectate lyases with endo-polygalacturonase or exo-pectate lyase or both cause maceration.Erwinia carotovora subsp. carotovora causes soft rot on many plants. Soft rot results from the activity of extracellular enzymes (11). Extracellular enzymes produced by E. carotovora subsp. carotovora capable of degrading plant cell wall and plant cell membrane components include the following: endo-pectate lyase, endo-polygalacturonase, cellulase, protease, phosphatidase C, and phosholipase A (2,8,9,18,20,22). In an effort to clarify the role of Erwinia pectic enzymes in pathogenesis, several laboratories have isolated genes encoding enzymatic pathogenic determinants from Erwinia spp. (1, 6, 10, 17a, 23).Pectolytic enzymes are key factors in soft rot pathogenesis (for a review, see reference 5); however, the individual roles of the six or more pectolytic enzymes produced by E. carotovora subsp. carotovora EC14 (17a,18) MATERIALS AND METHODS Bacterial strains and plasmids. The bacterial strains and plasmids constructed or used or both constructed and used in this research are listed in Table 1 and in Table 2, respectively. Strain names with the prefix L-indicate designations for strains in the culture collection of G. H. Lacy.Chromosomal DNA isolation. Chromosomal DNA was isolated from strain EC14 as previously reported (17a).Cloning and construction of recombinant strains. Strain EC14 chromosomal DNA was partially digested with BamHI; ligated into dephosphorylated, BamHI-cleaved pBR322 DNA; and transformed into E. coli HB101 by procedures described previously (17a). Transformants with chimeric plasmids had ampicillin-resistant, tetracyclinesensitive phenotypes when screened on YT agar medium (13) containing ampicillin (30 jig/ml) or ampicillin and tetracycline (10 ,ug/ml). Transformants producing pectolytic or cellulolytic enzymes were detected on ampicillin-amended PEC-YA medium (19) or...

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“…Pectin-degrading enzymes have been shown to be important in pathogenesis by a number of bacterial plant pathogens (6,8), most notably the soft rot erwinias. Purified Erwinia pectic enzymes macerate plant tissue and cause plant cell death (2,23), and cloned Erwinia pectic enzyme genes confer the ability to macerate plant tissue on the non-plant pathogen E. coli (7,15,27,31).…”

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Analysis of the Pseudomonas solanacearum polygalacturonase encoded by pglA and its involvement in phytopathogenicity

1988

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A major endopolygalacturonase excreted by Pseudomonas solanacearum was purified to >95 % homogeneity and shown to have an isoelectric point of 9.0 and a subunit molecular mass of 52 kilodaltons (kDa). The gene encoding this enzyme (pglA) was isolated from a genomic library of P. solanacearum DNA based on its expression in Escherichia coli and shown to be contained on a 1.8-kilobase DNA fragment. The identity of the pglA gene product and the 52-kDa polygalacturonase was demonstrated by immunoadsorption and isoelectric focusing experiments. The cloned pglA gene was apparently expressed from its own promoter in E. coli and its product was partially secreted into the periplasm. The pglA gene was insertionally inactivated in vitro and used to mutate the chromosomal pgL4 gene of P. solanacearum by marker exchange mutagenesis. The resulting mutant strain was deficient in production of the 52-kDa polygalacturonase and took twice as long to wilt and kill tomato plants as the wild-type parent in plant bioassay experiments. Complementation in trans with the wild-type cloned pg4 gene restored virulence to near wild-type levels. The data indicate that the pglA gene is important, but not absolutely necessary, for pathogenesis.

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Pectate Lyase Regulation and Bacterial Soft-Rot Pathogenesis

Cited by 47 publications

References 70 publications

Analysis of eight out genes in a cluster required for pectic enzyme secretion by Erwinia chrysanthemi: sequence comparison with secretion genes from other gram-negative bacteria

Analysis of eight out genes in a cluster required for pectic enzyme secretion by Erwinia chrysanthemi: sequence comparison with secretion genes from other gram-negative bacteria

Requirement for two or more Erwinia carotovora subsp. carotovora pectolytic gene products for maceration of potato tuber tissue by Escherichia coli

Analysis of the Pseudomonas solanacearum polygalacturonase encoded by pglA and its involvement in phytopathogenicity

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