Host pathogen interaction between European strains of red algae 'Bangia' and oomycete Olpidiopsis porphyrae var. scotiae, and phylogenetic analysis for European 'Bangia' strains
Olpidiopsis is one of the main disease causal agents affecting Neoprophyra (commonly known as Nori) sea farms. A recent study described a Scottish variety in the Scottish water Olpidiopsis porphyrae var. scotiae. I studied the resistance of 11 red algae (‘Bangia’) strains against this new described variety by using microscopy inspection and qPCR assay. Results from microscopy inspection showed significant effect for ‘Bangia’ strains on incubation period (days from inoculation until observation of the first symptom) and the percentage of infection (the number of infected cells as percentage). qPCR assay showed also significant effect for the ‘Bangia’ strain on normalized Pfaffl ratio suggesting different levels of resistance for different ‘Bangia’ strains. Moreover, I studied the phylogeny for 20 ‘Bangia’ strains collected from France and Scotland by using rbcL and cox1 molecular markers and I compared the phylogenetic position of our ‘Bangia’ strains with available information for the phylogeny of ‘Bangia’ strains around the world. My study showed that eight strains are belong to ‘Bangia’2 clade, 11 strains belong to ‘Bangia’3 clade, and one freshwater strain belongs to ‘Bangia’ clade. Overall, there was different resistance reaction from different ‘Bangia’ strains against the pathogen suggesting different levels of host susceptibility which is not related to the clade.
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