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.