Attachment, penetration and early host defense mechanisms during the infection of filamentous brown algae by Eurychasma dicksonii

Amerssa Tsirigoti, Gordon W. Beakes, Cecile Herve, Claire M. M. Gachon, Christos Katsaros

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Eurychasma dicksonii is one of the most common and widespread marine pathogens and attacks a broad spectrum of more than 45 brown algal species. The present study focuses on the mechanism used by the pathogen to attach on the host cell wall and force its way into algal cells. Ultrastructural examination revealed a needle-like structure which develops within the attached spore and extends along its main axis. Particular cell wall modifications are present at the basal part of the spore (adhesorium pad) and guide the needle-like tool to penetrate perpendicularly the host cell wall. The unique injection mechanism is shared with Haptoglossa species which suggests that this is an important characteristic of early diverging oomycetes. Furthermore, the encystment and adhesion mechanism of E. dicksonii shows significant similarities with other oomycetes, some of which are plant pathogens. Staining and immunolabelling techniques showed the deposition of β-1,3-glucans on the host cell wall at the pathogen penetration site, a strategy similar to physical responses previously described only in infected plant cells. It is assumed that the host defense in terms of callose-like deposition is an ancient response to infection.
Original languageEnglish
Pages (from-to)845-856
Number of pages11
Issue number3
Early online date11 Nov 2014
Publication statusPublished - May 2015


  • Brown algae
  • Eurychasma
  • Host defense
  • Injection mechanism
  • Oomycete
  • Parasite

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