The Chondrus crispus-Acrochaete operculata host-pathogen association, a novel model in glycobiology and applied phycopathology

A review is presented of ongoing research on the oligosaccharide signalsinvolved in cell-cell recognition in the Chondrus crispus-Acrochaete operculata host-pathogen association. In this pathosystem,the host gametophytes are resistant to the pathogen, whereas thesporophytic generation is susceptible to infection. The virulence of thegreen algal pathogen is mediated by the recognition of carrageenanoligosaccharides released from its red algal host: kappa-carrageenanoligosaccharides inhibit A. operculata virulence while lambdacarrageenan oligosaccharides enhance its pathogenicity. It appears that therecognition of A. operculata by C. crispus also involves anoligosaccharidic signal. This signal is present in the non-virulent form of thepathogen whereas it is absent from the virulent form. Altogether thispathosystem offers a unique model to investigate the recognition ofoligosaccharide signals in plant-pathogen interactions. The possibleapplications of this research to develop new strategies for disease controlin maricultured algal crops are discussed.