Genomic variants’ analysis of Escherichia coli K-12 cells resistant to phage T7 infection

In the laboratory of metagenome analysis there were obtained Escherichia coli BW25113 mutants resistant to infection with the T7 phage and possessing a mucoid phenotype. Tasks were set in carrying out whole genome sequencing of mutants and their further bioinformatic processing on the basis of bioinformatic analysis in order to determine the mechanism of acquiring resistance to bacteriophages. Bioinformatic analysis included searching genome variants for the strains under investigation by Bowtie2 and SNP calling software, prediction the importance of genome variants by IGV-browser, and predicting functions of the variants by the use of EcoCyc and NCBI open databases. As a result, mutations in the locus of genes igaA, RcsC, yjbF, yjbG, and yjbH affecting the components of the Rcs signal transmission cascade, the main regulator of the expression of the yjbEFGH gene cluster, responsible for the synthesis of colanic acid, were detected taking into account the results of previous research. Thus, it was proved that the discovered resistance arose during the selection of mutants forming a colane capsule that prevents the adsorption of phage particles by creating a physical barrier in front of the phage receptor on the cell surface. Genetic screenings adjusted to new combinations of phage attacks on bacteria are of great importance to get an insight into the ways of phages’ and phenotypes’ infecting and resistance genotypes. Currently, the insight into the reasons of bacteria resistance to phages is insufficient, therefore, the paper is aimed at filling the gap.