Role of motility and chemotaxis in the pathogenesis of Dickeya dadantii 3937 (ex Erwinia chrysanthemi 3937).
نویسندگان
چکیده
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.
منابع مشابه
SlyA, a MarR family transcriptional regulator, is essential for virulence in Dickeya dadantii 3937.
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PhoP-PhoQ Two-Component System Required for Colonization Leading to Virulence of Dickeya dadantii 3937 in planta
Dickeya dadantii (formerly Erwinia chrysanthemi, Pectobacterium chrysanthemi) is a necrotrophic, intracellular, plant pathogenic enterobacterium that induces soft rot diseases on a great variety of plants worldwide by secreting mainly multiple plant cell wall-degrading enzymes including pectinases, cellulases and proteases1. Additional factors that contribute to its pathogenicity are exopolysac...
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BACKGROUND Dickeya dadantii is a necrotrophic pathogen causing disease in many plants. Previous studies have demonstrated that the type III secretion system (T3SS) of D. dadantii is required for full virulence. HrpL is an alternative sigma factor that binds to the hrp box promoter sequence of T3SS genes to up-regulate their expression. METHODOLOGY/PRINCIPAL FINDINGS To explore the inventory o...
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عنوان ژورنال:
- Microbiology
دوره 155 Pt 2 شماره
صفحات -
تاریخ انتشار 2009