Whole-genome sequencing of the Streptomyces coelicolor bldA39 mutant (J1700) reveals hundreds of previously unknown mutations

We report the genome sequence of the <i>bldA39</i> (J1700) mutant of <i>Streptomyces coelicolor</i>, a historically important strain that is deficient in sporulation and antimicrobial production. The <i>S. coelicolor</i> J1700 strain was used extensively from the 1980s onwards to underpin important discoveries in development and antibiotic production in <i>Streptomyces</i>. The <i>bldA</i> gene encodes a leucyl tRNA, required for the translation of the rare TTA codon found in ~2% of genes in <i>Streptomyces</i>. The whole genome of <i>S. coelicolor</i> J1700 was obtained via Illumina sequencing and mapped to the <i>S. coelicolor</i> M145 reference genome. Analysis of the genome sequence compared to <i>S. coelicolor</i> M145 identified the known <i>bldA39</i> mutation (T>C) and revealed more than 300 further mutations, likely associated with the <i>S. coelicolor</i> J1501 genetic background the strain was created in, including the nature of the <i>hisA1</i> and <i>uraA1</i> alleles used extensively in genetic mapping experiments and several mutations in natural product biosynthetic gene clusters. This work highlights the importance of whole-genome sequencing of historically important strains.