Isolate-specific resistance to the algicidal bacterium Kordia algicida in the diatom Chaetoceros genus

Algicidal bacteria can lyse phytoplankton cells, thereby contributing to algal bloom dynamics in the oceans. The target specificity of these bacteria determines their ecological impact. While species specificity of algicidal bacteria is documented, little is known about intra-species variability of their activity against phytoplankton. We describe variability in the Chaetoceros genus (Bacillariophyceae) to resist the lytic activity of the algicidal Flavobacterium Kordia algicida. This variability is evident between different Chaetoceros species, but even intra-specific variability of resistance is observed within one phytoplankton sample. This proves an ecological role of the individuality of diatom cells within a bloom.