Identification of novel virulence genes and metabolic pathways required for full fitness of Pseudomonas savastanoi pv. savastanoi in olive (Olea europaea) knots

Authors

  • Isabel M. Matas,

    1. Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Área de Genética, Facultad de Ciencias, Málaga, Spain
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  • Lotte Lambertsen,

    1. Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Área de Genética, Facultad de Ciencias, Málaga, Spain
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  • Luis Rodríguez-Moreno,

    1. Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Área de Genética, Facultad de Ciencias, Málaga, Spain
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  • Cayo Ramos

    Corresponding author
    • Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Área de Genética, Facultad de Ciencias, Málaga, Spain
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Author for correspondence:

Cayo Ramos

Tel: +34 95213 1955

Email: crr@uma.es

Summary

  • Comparative genomics and functional analysis of Pseudomonas syringae and related pathogens have mainly focused on diseases of herbaceous plants; however, there is a general lack of knowledge about the virulence and pathogenicity determinants required for infection of woody plants.
  • Here, we applied signature-tagged mutagenesis (STM) to Pseudomonas savastanoi pv. savastanoi during colonization of olive (Olea europaea) knots, with the goal of identifying the range of genes linked to growth and symptom production in its plant host.
  • A total of 58 different genes were identified, and most mutations resulted in hypovirulence in woody olive plants. Sequence analysis of STM mutations allowed us to identify metabolic pathways required for full fitness of P. savastanoi in olive and revealed novel mechanisms involved in the virulence of this pathogen, some of which are essential for full colonization of olive knots by the pathogen and for the lysis of host cells.
  • This first application of STM to a P. syringae-like pathogen provides confirmation of functional capabilities long believed to play a role in the survival and virulence of this group of pathogens but not adequately tested before, and unravels novel factors not correlated previously with the virulence of other plant or animal bacterial pathogens.

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