TY - JOUR TI - Assessing life history tradeoffs in host range mutants of RNA bacteriophage phi6 DO - https://doi.org/doi:10.7282/T33T9K6F PY - 2015 AB - Studies on host range mutation and its effects on phage fitness are common for bacteriophage phi6. Expanding to a novel host can occur through a large number of mutations which provide a new resource for use typically at a decreased level of reproduction. Secondary mutations developed during evolution on the novel host can raise phage fitness but may also lead to specialization on that host. Again, the mutations that are beneficial on the novel host are usually detrimental on the initial host. Studying phage life history traits such as fecundity (reproduction rate and size) as well as competitive ability on the hosts may help determine where fitness is lost. Here I used host range mutants of phi6 that were previously evolved on P. pseudoalcaligenes East River Isolate A (ERA). I performed paired growth assays on original host P. syringae pathovar phaseolicola (PP) and burst assays on both PP and ERA to determine the effects of these mutations on the phage’s reproductive ability. My selection of phages includes a specialist on PP, a specialist on ERA, and generalists capable of infecting more than one host. Paired growth assays showed that two of the five mutants suffer a fitness cost relative to the wild type ancestor on PP. However, burst assays showed no significant difference between the wild type and evolved mutants on PP. Burst assays on ERA showed that several mutants improved their burst time and all mutants improved their burst sizes compared to their ancestor on that host. The evolved mutants were not able to separate themselves from one another. Mutants separated by one mutation showed significant effects from these differences. My results suggest that burst and fitness assays can be a component for assessing differences in phage life history but need to be supplemented with further experimentation. KW - Microbial Biology KW - Bacteriophages LA - eng ER -