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Diversity in CRISPR‐based immunity protects susceptible genotypes by restricting phage spread and evolution
Author(s) -
Common Jack,
WalkerSünderhauf David,
Houte Stineke,
Westra Edze R.
Publication year - 2020
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/jeb.13638
Subject(s) - biology , lytic cycle , crispr , genotype , genetic diversity , genetics , bacteriophage , host (biology) , immune system , population , evolutionary biology , gene , virus , demography , escherichia coli , sociology
Diversity in host resistance often associates with reduced pathogen spread. This may result from ecological and evolutionary processes, likely with feedback between them. Theory and experiments on bacteria–phage interactions have shown that genetic diversity of the bacterial adaptive immune system can limit phage evolution to overcome resistance. Using the CRISPR–Cas bacterial immune system and lytic phage, we engineered a host–pathogen system where each bacterial host genotype could be infected by only one phage genotype. With this model system, we explored how CRISPR diversity impacts the spread of phage when they can overcome a resistance allele, how immune diversity affects the evolution of the phage to increase its host range and if there was feedback between these processes. We show that increasing CRISPR diversity benefits susceptible bacteria via a dilution effect, which limits the spread of the phage. We suggest that this ecological effect impacts the evolution of novel phage genotypes, which then feeds back into phage population dynamics.