Molecular cloning of a polygalacturonate lyase gene from Xanthomonas campestris pv. campestris and role of the gene product in pathogenicity

Dow, J. Maxwell; Milligan, D. E.; Jamieson, Lee; Barber, C. E.; Daniels, Michael J.

doi:10.1016/0885-5765(89)90081-7

Cited by 37 publications

(28 citation statements)

References 20 publications

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“…The two polygalacturonase genes are XCC3459 and XC_0705 for pehA and XCC2266 and XC_1849 for pglA (da Silva et al, 2002;Qian et al, 2005). None of these genes have been studied, although three forms of pectate lyases have been reported (Dow et al, 1987(Dow et al, , 1989. Recently, it was found that a mutation in pglA only slightly reduced the level of polygalacturonase activity (Chien, 2006), indicating that PglA is not the major polygalacturonase in Xcc.…”

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confidence: 99%

Regulation of the pehA gene encoding the major polygalacturonase of Xanthomonas campestris by Clp and RpfF

Hsiao

Zheng

et al. 2008

Microbiology

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Exopolysaccharide and several extracellular enzymes of Xanthomonas campestris pv. campestris (Xcc), the causative agent of black rot in crucifers, are virulence factors. In this study, sequence and mutational analysis has demonstrated that Xcc pehA encodes the major polygalacturonase, a member of family 28 of the glycosyl hydrolases. Using the 59 RACE (rapid amplification of cDNA ends) method, the pehA transcription initiation site was mapped at 102 nt downstream of a Clp (cAMP receptor protein-like protein)-binding site. Transcriptional fusion assays showed that pehA transcription is greatly induced by polygalacturonic acid, positively regulated by Clp and RpfF (an enoyl-CoA hydratase homologue which is required for the synthesis of cis-11-methyl-2-dodecenoic acid, a low-molecular-mass diffusible signal factor), subjected to catabolite repression, which is independent of Clp or RpfF, and repressed under conditions of oxygen limitation or nitrogen starvation. Our findings extend previous work on Clp and RpfF regulation to show that they both influence the expression of pehA in Xcc.

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Section: Introductionmentioning

confidence: 99%

Regulation of the pehA gene encoding the major polygalacturonase of Xanthomonas campestris by Clp and RpfF

Hsiao

Zheng

et al. 2008

Microbiology

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“…campestris incites black rot is not known. Mutants that lack degradative enzymes and extracellular polysaccharides (EPS) were nonpathogenic (9), whereas mutants defective only in cellulase, protease, polygalacturonate lyase, or EPS production were still able to cause black rot (8,11,31,35,38 …”

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A plant-inducible gene of Xanthomonas campestris pv. campestris encodes an exocellular component required for growth in the host and hypersensitivity on nonhosts

Kamoun

Kado

1990

J Bacteriol

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Using Tn4431, a transposon that allows transcriptional fusions to a promoterless luciferase (lux) operon, we have isolated a nonpathogenic mutant of Xanthomonas campestris pv. campestris, i.e., JS111, that does not incite any of the black rot symptoms on all tested cruciferous host plants (J. J. Shaw, L. G. Settles, and C. I. Kado, Mol. Plant Microbe Interact. 1:3945, 1988). In the study reported here, we determined that in contrast to the wild-type strain, JS111 is unable to induce a hypersensitive necrotic response on nonhost plants such as datura, tomato, and cucumber, suggesting that JS111 is a nonpathogenic, nonhypersensitive Hrp mutant. JS111 displayed culture growth rates, exopolysaccharide production, and protease, pectate lysase, cellulase, amylase, and phosphatase activities comparable to those of the wild-type strain. However, the growth of JS111 in host leaves was markedly attenuated. Coinoculation of JS111 with the wild-type strain in cauliflower or radish leaves rescued the growth deficiency of the mutant to normal levels. The locus mutated in JS11 was cloned and named hrpXc, and transcriptional and genetic complementation analyses of the hrpXc locus were conducted. The regulation of hrpXc expression was also investigated in vitro and in planta, using fusions to a lux or chloramphenicol acetyltransferase reporter gene. The hrpXc gene was found to be strongly induced in radish leaves. This is the first report and analysis of a hrp locus from a Xanthomonas species.In recent years, the application of molecular genetic approaches to plant pathogenic bacteria has led to the identification and isolation of a number of genes involved in the interaction between the bacterium and the plant. These genes can be tentatively classified into four groups relative to the phenotype they confer on the bacteria. (i) hrp (hypersensitive response and pathogenicity) genes are required for pathogenicity on hosts and for the induction of a hypersensitive response (HR) on nonhost plants (1, 2, 23). (ii) dsp (disease-specific) genes are necessary for pathogenicity but do not affect HR induction on nonhosts (6). (iii) avr (avirulence) genes confer race-or cultivar-specific interactions. The avirulence genes are dominant genes and restrict the host range of the bacteria to the cultivars that contain a complementary resistance gene(s) (36, 37). (iv) Of considerable importance are the hsv (host-specific virulence) genes that have been isolated from bacteria with wide host ranges and are required for pathogenicity on only some of the host plants (13, 14, 28; D. Gabriel, ASM News 52:19-25, 1986). hsv genes can extend the host range when introduced in narrow-host-range strains (25,39).In this paper, we report the identification and characterization of a hrp gene from Xanthomonas campestris pv. campestris, the causal agent of the black rot of crucifers, a worldwide and economically important plant disease (40). Hydathodes are the principal natural mode of entry in the plant, although secondary entry sites can develop in the roots ...

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“…(18), Xanthomonas campestris pv. campestris (8), Yersinia pseudotuberculosis (28), and Aspergillus nidulans (7), have recently been cloned and characterized. Despite its pathologic and ecologic importance, the pel gene of fluorescent pseudomonads has not yet been carefully examined.…”

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Cloning of pectate lyase gene pel from Pseudomonas fluorescens and detection of sequences homologous to pel in Pseudomonas viridiflava and Pseudomonas putida

Liao

1991

J Bacteriol

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Pectate lyase (PL) depolymerizes pectin and other polygalacturonates (PGAs) and is thought to play a role in bacterial invasion of plants. Production of PL by the soft-rotting pathogen Pseudomonasfluorescens CY091 is regulated by Ca2+. In the presence of Ca2+, this bacterium constitutively synthesizes PL in media containing glucose, glycerol, or PGA and excretes over 87% of total PL into culture fluids. In the absence of Ca2 , the organism fails to use PGA as a carbon source and produces very low levels of PL in media containing glucose or glycerol. Of the small amount of PL produced by the bacterium in Ca2+-deficient media, over 78% was detected within the cells, indicating that Ca2' is critical not only for the production but also for the secretion of PL. The pel gene, encoding an alkaline PL (p1 10.0, Mr 41,000) was cloned and located on the overlapping region of a 4.3-kb Sall and a 7.1-kb EcoRI fragment. Pseudomonas fluorescens is a heterogenous species and consists of a diversity of ecologic and physiological groups (36). Certain strains of this species are postharvest pathogens of plants, which cause soft rot of fruits and vegetables in storage and at markets (25). Soft-rotting P. fluorescens (often referred to as P. marginalis) is capable of degrading pectic components of plant cell walls by producing a wide variety of pectolytic enzymes, including pectin methylesterase (30), pectin lyase (33, 35), polygalacturonase (10,30,42), and pectate lyase (PL) (9,10,12,22,30,42). Production of methylesterase, pectin lyase, and polygalacturonase is rare and has been detected only in a few strains (30,33,35,42). With the exception of one strain (30), all of the soft-rotting pseudomonads so far studied produce PL. Thus, it is generally believed that PL is the principal or sole enzyme responsible for tissue maceration caused by most strains of P. fluorescens and P. viridiflava (22, 24).The PL system of P. fluorescens is considerably different from that of Erwinia spp., although soft-rot symptoms caused by the two organisms are similar. In Erwinia spp., all strains so far studied produce three to five PL isozymes (pl 4.5 to 10.0) (18), whereas in P. fluorescens, all eight strains recently examined in our laboratory produce one or possibly two PLs (22). Furthermore, production of PLs in Erwinia spp. is induced by pectic substrates and subjected to catabolite or self-catabolite repression (18). In P. fluorescens, however, the mode of PL production varies considerably among strains and can be constitutive (30,42) or inducible (9,30,43). In some strains, PL production is induced by pectic substances in a mechanism resembling that previously demonstrated in Erwinia spp. (18). In others, the regulatory factors or mechanisms have not been clearly defined. For example, Zucker and Hankin (43) showed that a nonpectolytic isolate of P. fluorescens can be converted to pectolytic by a series of subcultures in media containing pectin or plant tissue extracts. Hildebrand (10) reported that expression of a pectolytic phenotype in fluo...

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Molecular cloning of a polygalacturonate lyase gene from Xanthomonas campestris pv. campestris and role of the gene product in pathogenicity

Cited by 37 publications

References 20 publications

Regulation of the pehA gene encoding the major polygalacturonase of Xanthomonas campestris by Clp and RpfF

Regulation of the pehA gene encoding the major polygalacturonase of Xanthomonas campestris by Clp and RpfF

A plant-inducible gene of Xanthomonas campestris pv. campestris encodes an exocellular component required for growth in the host and hypersensitivity on nonhosts

Cloning of pectate lyase gene pel from Pseudomonas fluorescens and detection of sequences homologous to pel in Pseudomonas viridiflava and Pseudomonas putida

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