Bioactivities and genome insights of a thermotolerant antibiotics-producing Streptomyces sp. TM32 reveal its potentials for novel drug discovery.

A way to defeat antimicrobial resistance (AMR) crisis is to supply novel drugs to the pharmaceutical industry. This effort leads to a global call for seeking the beneficial microbes from underexplored habitats. To support this call, we isolated Streptomyces sp. TM32 from the rhizosphere soil of a medicinal plant, turmeric (Curcuma longa L.). TM32 exhibited strong antimicrobial activities against both human and plant pathogens, including an AMR pathogen, Staphylococcus haemolyticus MR-CoNS. Surprisingly, such antimicrobial results of TM32's autoclaved crude extract remained the same. Based on the genome data analysis, TM32 belongs to the same genomic species with Streptomyces sioyaensis DSM 40032 ^T , supported by the relatively high-average nucleotide identity values (ANIb: 96.80% and OrthoANIu: 97.14%) and in silico DNA-DNA relatedness value of 75.40%. Importantly, the gene annotation analyses revealed that TM32's genome contains various genes encoding the biosynthesis of either known or unknown antibiotics and some metabolites involved in plant growth-promoting traits. However, bioactivities and genome data comparison of TM32 and DSM 40032 ^T showed a set of apparent differences, for example, antimicrobial potentials, genome size, number, and occurrence of coding DNA sequences in the chromosomes. These findings suggest that TM32 is a new strain of S. sioyaensis and serves as an emerging source for further discovery of valuable and novel bioactive compounds.
(© 2019 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)