Dickeya dadantii 3937 (ex Erwinia chrysanthemi), a member of the Enterobacteriaceae, causes soft rot in many economically important crops. A successful pathogen has to reach the interior of the plant in order to cause disease. To study the role of motility and chemotaxis in the pathogenicity of D. dadantii 3937, genes involved in the chemotactic signal transduction system (cheW, cheB, cheY and cheZ) and in the structure of the flagellar motor (motA) were mutagenized. All the mutant strains grew like the wild-type in culture media, and the production and secretion of pectolytic enzymes was not affected. As expected, the swimming ability of the mutant strains was reduced with respect to the wild-type: motA (94 %), cheY (80 %), cheW (74 %), cheB (54 %) and cheZ (48 %). The virulence of the mutant strains was analysed in chicory, Saintpaulia and potato. The mutant strains were also tested for their capability to enter into Arabidopsis leaves. All the mutants showed a significant decrease of virulence in certain hosts; however, the degree of virulence reduction varied depending on the virulence assay. The ability to penetrate Arabidopsis leaves was impaired in all the mutants, whereas the capacity to colonize potato tubers after artificial inoculation was affected in only two mutant strains. In general, the virulence of the mutants could be ranked as motA<cheY<cheB=cheW<cheZ, which correlated with the degree to which swimming was affected. These results clearly indicate that motility plays an important role in the pathogenicity of this bacterium.
AlfanoJ. R.,
CollmerA.1997; The type III (Hrp) secretion pathway of plant pathogenic bacteria: trafficking harpins. Avr proteins, and death. J Bacteriol 179:5655–5662
BauerD. W.,
BogdanoveA. J.,
BeerS. V.,
CollmerA.1994; Erwinia chrysanthemi hrp genes and their involvement in soft rot pathogenesis and elicitation of the hypersensitive response. Mol Plant Microbe Interact 7:573–581
BurallL. S.,
HarroJ. M.,
LiX.,
LockatellC. V.,
HimpslS. D.,
HebelJ. R.,
JohnsonD. E.,
MobleyH. L.2004; Proteus mirabilis genes that contribute to pathogenesis of urinary tract infection: identification of 25 signature-tagged mutants attenuated at least 100-fold. Infect Immun 72:2922–2938
BurkartM.,
ToguchiA.,
HarsheyR. M.1998; The chemotaxis system, but not chemotaxis, is essential for swarming motility in Escherichia coli . Proc Natl Acad Sci U S A 95:2568–2573
ButlerS. M.,
CamilliA.2004; Both chemotaxis and net motility greatly influence the infectivity of Vibrio cholerae . Proc Natl Acad Sci U S A 101:5018–5023
DonsL.,
ErikssonE.,
JinY.,
RottenbergM. E.,
KristenssonK.,
LarsenC. N.,
BrescianiJ.,
OlsenJ. E.2004; Role of flagellin and the two-component CheA/CheY system of Listeria monocytogenes in host cell invasion and virulence. Infect Immun 72:3237–3244
DowdJ. P.,
MatsumuraP.1997; The use of flash photolysis for a high-resolution temporal and spatial analysis of bacterial chemotactic behaviour: CheZ is not always necessary for chemotaxis. Mol Microbiol 25:295–302
el HassouniM.,
ChambostJ. P.,
ExpertD.,
Van GijsegemF.,
BarrasF.1999; The minimal gene set member msrA , encoding peptide methionine sulfoxide reductase, is a virulence determinant of the plant pathogen Erwinia chrysanthemi . Proc Natl Acad Sci U S A 96:887–892
FranzaT.,
SauvageC.,
ExpertD.1999; Iron regulation and pathogenicity in Erwinia chrysanthemi 3937: role of the Fur repressor protein. Mol Plant Microbe Interact 12:119–128
Llama-PalaciosA.,
Lopez-SolanillaE.,
Poza-CarrionC.,
Garcia-OlmedoF.,
Rodriguez-PalenzuelaP.2003; The Erwinia chrysanthemi phoP-phoQ operon plays an important role in growth at low pH, virulence and bacterial survival in plant tissue. Mol Microbiol 49:347–357
Lopez-SolanillaE.,
Garcia-OlmedoF.,
Rodriguez-PalenzuelaP.1998; Inactivation of the sapA to sapF locus of Erwinia chrysanthemi reveals common features in plant and animal bacterial pathogenesis. Plant Cell 10:917–924
Lopez-SolanillaE.,
Llama-PalaciosA.,
CollmerA.,
Garcia-OlmedoF.,
Rodriguez-PalenzuelaP.2001; Relative effects on virulence of mutations in the sap , pel , and hrp loci of Erwinia chrysanthemi . Mol Plant Microbe Interact 14:386–393
MiguelE.,
Poza-CarrionC.,
Lopez-SolanillaE.,
AguilarI.,
Llama-PalaciosA.,
Garcia-OlmedoF.,
Rodriguez-PalenzuelaP.2000; Evidence against a direct antimicrobial role of H2O2 in the infection of plants by Erwinia chrysanthemi . Mol Plant Microbe Interact 13:421–429
RodríguezA.,
GuilN.,
ShottonD. M.,
TrellesO.2004; Automatic analysis of the content of cell biological videos and database organization of their metadata descriptors. IEEE Trans Multimed 6:119–128
SambrookJ.,
FritschE. F.,
ManiatisT. A.1989Molecular Cloning: a Laboratory Manual , 2nd edn. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory;
SannaM. G.,
SimonM. I.1996; In vivo and in vitro characterization of Escherichia coli protein CheZ gain- and loss-of-function mutants. J Bacteriol 178:6275–6280
StephensB. B.,
LoarS. N.,
AlexandreG.2006; Role of CheB and CheR in the complex chemotactic and aerotactic pathway of Azospirillum brasilense . J Bacteriol 188:4759–4768
YamaguchiS.,
AizawaS.,
KiharaM.,
IsomuraM.,
JonesC. J.,
MacnabR. M.1986; Genetic evidence for a switching and energy-transducing complex in the flagellar motor of Salmonella typhimurium . J Bacteriol 168:1172–1179
YangS.,
PernaN. T.,
CookseyD. A.,
OkinakaY.,
LindowS. E.,
IbekweA. M.,
KeenN. T.,
YangC. H.2004; Genome-wide identification of plant-upregulated genes of Erwinia chrysanthemi 3937 using a GFP-based IVET leaf array. Mol Plant Microbe Interact 17:999–1008
YaoJ.,
AllenC.2006; Chemotaxis is required for virulence and competitive fitness of the bacterial wilt pathogen Ralstonia solanacearum . J Bacteriol 188:3697–3708