Role of motility and chemotaxis in the pathogenesis of Dickeya dadantii 3937 (ex Erwinia chrysanthemi 3937).
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.
Antúnez-Lamas
María
M
Departamento de Biotecnología, Universidad Politécnica de Madrid, E.T.S. Ingenieros Agrónomos, CBGP, Centro de Biotecnología y Genómica de Plantas, Avda Complutense S/N, E-28040 Madrid, Spain.
Cabrera-Ordóñez
Ezequiel
E
Departamento de Biotecnología, Universidad Politécnica de Madrid, E.T.S. Ingenieros Agrónomos, CBGP, Centro de Biotecnología y Genómica de Plantas, Avda Complutense S/N, E-28040 Madrid, Spain.
López-Solanilla
Emilia
E
Departamento de Biotecnología, Universidad Politécnica de Madrid, E.T.S. Ingenieros Agrónomos, CBGP, Centro de Biotecnología y Genómica de Plantas, Avda Complutense S/N, E-28040 Madrid, Spain.
Raposo
Rosa
R
CIFOR, Instituto Nacional Investigaciones Agrarias (INIA), C. Coruña km 7.5, 28040 Madrid, Spain.
Trelles-Salazar
Oswaldo
O
Departamento de Arquitectura de Computadores, E.T.S. de Ingeniería Informática, Campus de Teatinos, E-29071 Málaga, Spain.
Rodríguez-Moreno
Andrés
A
Departamento de Arquitectura de Computadores, E.T.S. de Ingeniería Informática, Campus de Teatinos, E-29071 Málaga, Spain.
Rodríguez-Palenzuela
Pablo
P
Departamento de Biotecnología, Universidad Politécnica de Madrid, E.T.S. Ingenieros Agrónomos, CBGP, Centro de Biotecnología y Genómica de Plantas, Avda Complutense S/N, E-28040 Madrid, Spain.
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002633:Chemotaxis; D016974:Dickeya chrysanthemi / Q000472:pathogenicity* / Q000502:physiology*; D005407:Flagella / Q000235:genetics / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D015398:Signal Transduction; D014774:Virulence
D001426:Bacterial Proteins