Sequencing adaptive laboratory evolution of umbrella toxin resistance
Streptomyces secrete toxigenic protein complexes that mediate congeneric competition. Known as umbrella toxins, these particles inhibit the growth of other species of Streptomyces in a highly selective manner. In order to determine the mechanism of umbrella toxin targeting specificity by identifying the Umb particle receptor, populations of S. griseus and S. antibioticus resistant to intoxication by Umb particles were evolved. These resistant populations were screened for individual isolates displaying resistance to treatment with Umb particles. Mutations responsible for conferring resistance to Umb particle intoxication were identified by sequencing the genomes of the resistant evolved isolates and comparing them to the genome of the Umb-sensitive ancestral strain. The genome of the S. griseus strain used was publicly available and could be used to align and compare the sequencing results for both the ancestor and the evolved isolates. There was no published genome for the strain of S. antibioticus used, so a whole genome sequence of this strain was generated before the sequences of the S. antibioticus ancestor and evolved isolates could be aligned and compared.