In Silico Analysis of PKS and NRPS Gene Clusters in Arisostatin- and Kosinostatin-Producers and Description of Micromonospora okii sp. nov.

Micromonospora sp. TP-A0316 and Micromonospora sp. TP-A0468 are producers of arisostatin and kosinostatin, respectively. Micromonospora sp. TP-A0316 showed a 16S rRNA gene sequence similarity of 100% to Micromonosporaoryzae CP2R9-1T whereas Micromonospora sp. TP-A0468 showed a 99.3% similarity to Micromonospora haikouensis 232617T. A phylogenetic analysis based on gyrB sequences suggested that Micromonospora sp. TP-A0316 is closely related to Micromonospora oryzae whereas Micromonospora TP-A0468 is an independent genomospecies. As Micromonospora sp. TP-A0468 showed some phenotypic differences to its closely related species, it was classified as a novel species, for which the name Micromonospora okii sp. nov. is proposed. The type strain is TP-A0468T (= NBRC 110461T). Micromonospora sp. TP-A0316 and M. okii TP-A0468T were both found to harbor 15 gene clusters for secondary metabolites such as polyketides and nonribosomal peptides in their genomes. Arisostatin-biosynthetic gene cluster (BGC) of Micromonospora sp. TP-A0316 closely resembled tetrocarcin A-BGC of Micromonospora chalcea NRRL 11289. A large type-I polyketide synthase gene cluster was present in each genome of Micromonospora sp. TP-A0316 and M. okii TP-A0468T. It was an ortholog of quinolidomicin-BGC of M. chalcea AK-AN57 and widely distributed in the genus Micromonospora.