TY  - JOUR
A1  - Coloma, Sebastian
A1  - Gaedke, Ursula
A1  - Sivonen, Kaarina
A1  - Hiltunen, Teppo
T1  - Frequency of virus-resistant hosts determines experimental community dynamics
JF  - Ecology : a publication of the Ecological Society of America
N2  - Parasites, such as bacterial viruses (phages), can have large effects on host populations both at the ecological and evolutionary levels. In the case of cyanobacteria, phages can reduce primary production and infected hosts release intracellular nutrients influencing planktonic food web structure, community dynamics, and biogeochemical cycles. Cyanophages may be of great importance in aquatic food webs during large cyanobacterial blooms unless the host population becomes resistant to phage infection. The consequences on plankton community dynamics of the evolution of phage resistance in bloom forming cyanobacterial populations are still poorly studied. Here, we examined the effect of different frequencies of a phage-resistant genotype within a filamentous nitrogen-fixing Nodularia spumigena population on an experimental plankton community. Three Nodularia populations with different initial frequencies (0%, 5%, and 50%) of phage-resistant genotypes were inoculated in separate treatments with the phage 2AV2, the green alga Chlorella vulgaris, and the rotifer Brachionus plicatilis, which formed the experimental plankton community subjected to either nitrogen-limited or nitrogen-rich conditions. We found that the frequency of the phage-resistant Nodularia genotype determined experimental community dynamics. Cyanobacterial populations with a high frequency (50%) of the phage-resistant genotype dominated the cultures despite the presence of phages, retaining most of the intracellular nitrogen in the plankton community. In contrast, populations with low frequencies (0% and 5%) of the phage-resistant genotype were lysed and reduced to extinction by the phage, transferring the intracellular nitrogen held by Nodularia to Chlorella and rotifers, and allowing Chlorella to dominate the communities and rotifers to survive. This study shows that even though phages represent minuscule biomass, they can have key effects on community composition and eco-evolutionary feedbacks in plankton communities.
KW  - cyanobacteria
KW  - eco-evolutionary feedbacks
KW  - experimental evolution
KW  - host-parasite interaction
KW  - phage resistance
KW  - predator-prey interaction
Y1  - 2018
U6  - https://doi.org/10.1002/ecy.2554
SN  - 0012-9658
SN  - 1939-9170
VL  - 100
IS  - 1
PB  - Wiley
CY  - Hoboken
ER  -