title: Swimming and twitching motility are essential for attachment and virulence of Pantoea ananatis in onion seedlings.
abstract: Pantoea ananatis is a widespread phytopathogen with a broad host range. Despite its ability to infect economically important crops, such as maize, rice and onion, relatively little is known about how this bacterium infects and colonizes host tissue or spreads within and between hosts. To study the role of motility in pathogenicity, we analysed both swimming and twitching motility in P. ananatis LMG 20103. Genetic recombineering was used to construct four mutants affected in motility. Two flagellar mutants were disrupted in the flgK and motA genes, required for flagellar assembly and flagellar rotation, respectively. Similarly, two twitching motility mutants were generated, impaired in the structure (pilA) and functioning (pilT) of the type IV pili. The role of swimming and twitching motility during the infection cycle of P. ananatis in onion seedlings was determined by comparing the mutant- and wild-type strains using several in vitro and in planta assays. From the results obtained, it was evident that flagella aid P. ananatis in locating and attaching to onion leaf surfaces, as well as in pathogenicity, whereas twitching motility is instrumental in the spread of the bacteria on the surface once attachment has occurred. Both swimming and twitching motility contribute towards the ability of P. ananatis to cause disease in onions.
authors.affiliation: Department of Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002 South Africa.
authors.forename: Tania
authors.initials: T
authors.lastname: Weller-Stuart
authors.affiliation: Department of Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002 South Africa.|Cell and Molecular Sciences, The James Hutton Institute, Dundee, DD2 5DA UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Toth
authors.affiliation: Department of Microbiology, Centre of Microbial Ecology and Genomics (CMEG), University of Pretoria, Pretoria, 0002 South Africa.
authors.forename: Pieter
authors.initials: P
authors.lastname: De Maayer
authors.affiliation: Department of Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002 South Africa.
authors.forename: Teresa
authors.initials: T
authors.lastname: Coutinho
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D036781:Fimbriae Proteins / Q000378:metabolism; D005407:Flagella / Q000378:metabolism; D019697:Onions / Q000382:microbiology*; D020636:Pantoea / Q000472:pathogenicity*; D010935:Plant Diseases / Q000382:microbiology; D036226:Seedlings / Q000382:microbiology*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D036781:Fimbriae Proteins
keywords: Pantoea ananatis; attachment; dispersal; flagella; motility; type IV pili; virulence