Genomic characterization and comparison of seven Myoviridae bacteriophage infecting Bacillus thuringiensis

Abstract

Bacillus thuringiensis Kurstaki, a bacterium that is a source of biopesticides and a safe simulant for pathogenic Bacillus species, was used to isolate seven unique bacteriophages. The phage genomes were sequenced and ranged in size from 158,100 to 163,019 bp encoding 290-299 genes, and the GC content of ~38% was similar to that of the host bacterium. All phages had terminal repeats 2-3 kb long. Three of the phages encoded tRNAs and three contained a self-splicing intron in the DNA polymerase gene. They were categorized as a single cluster (>60% nucleotide conservation) containing three subclusters (>80% nucleotide conservation), supported by genomic synteny and phylogenetic analysis. Considering the published genomes of phages that infect the genus Bacillus and noting the ability of many of the Bacillus cereus group phages to infect multiple species, a clustering system based on gene content is proposed.

Complete Genome Sequence of Bacillus Phage Belinda from Grand Cayman Island

“…Belinda was discovered in 2015 in soil from George Town, Grand Cayman Island (global positioning system [GPS] coordinates 19°17′35.3″N 81°23′04.8″W), having been isolated after soil enrichment with Bt DSM 350. Belinda and similar phages isolated on Bt DSM 350 also infected Bacillus thuringiensis kurstaki at about the same rate but do not infect more distantly related Bacillus species, as reported for C1 phages isolated on B. thuringiensis kurstaki ( 2 ).…”

Complete Genome Sequences of Bacillus Phages DirtyBetty and Kida

“…Neither phage has tRNAs present in its sequence. The two phages share 94% query coverage and 95% identity to each other, as well as similarly high values to other published cluster C1 Bacillus phages (10–13). They share 278 protein families (92% of their proteins), or phams (as described in reference 9), and relatively few protein-coding genes that are present in only one of these phages.…”

Genome Sequence of Bacillus cereus Group Phage SalinJah

“…However, the average ± standard deviation (SD) ANI among established and presumptive subcluster C1 phages is 0.92 ± 0.03, whereas the average ± SD ANI of SalinJah and Helga with C1 subcluster members is only 0.79 ± 0.01. This is below the 0.80 threshold established for subclusters ( 5 ). Together with differences observable through phylogenetic analysis and whole-genome alignment ( 6 ), this suggests the need for the creation of a new subcluster encompassing SalinJah and Helga.…”

“…KJ489399) and Megatron (accession no. KJ489401) in the above-mentioned respects, as well as in the presence of a large noncoding region, the lack of tRNA genes, and by encoding the same group I endolysins ( 5 ). In contrast, SalinJah shows lower ANI with phages in other C subclusters, with an ANI of 0.63, 0.62, and 0.59 compared to members of subclusters C2, C3, and C4, respectively.…”