Streptomyces differentiation in liquid cultures as a trigger of secondary metabolism

We thank the Spanish “Ministerio de Economía y Competitividad” (MINECO; BIO2015-65709-R) for financial support

ArgR of Streptomyces coelicolor is a pleiotropic transcriptional regulator: effect on the transcriptome, antibiotic production, and differentiation in liquid cultures

[EN] ArgR is a well-characterized transcriptional repressor controlling the expression of arginine and pyrimidine biosynthetic genes in bacteria. In this work, the biological role of Streptomyces coelicolor ArgR was analyzed by comparing the transcriptomes of S. coelicolor ΔargR and its parental strain, S. coelicolor M145, at five different times over a 66-h period. The effect of S. coelicolor ArgR was more widespread than that of the orthologous protein of Escherichia coli, affecting the expression of 1544 genes along the microarray time series. This S. coelicolor regulator repressed the expression of arginine and pyrimidine biosynthetic genes, but it also modulated the expression of genes not previously described to be regulated by ArgR: genes involved in nitrogen metabolism and nitrate utilization; the act, red, and cpk genes for antibiotic production; genes for the synthesis of the osmotic stress protector ectoine; genes related to hydrophobic cover formation and sporulation (chaplins, rodlins, ramR, and whi genes); all the cwg genes encoding proteins for glycan cell wall biosynthesis; and genes involved in gas vesicle formation. Many of these genes contain ARG boxes for ArgR binding. ArgR binding to seven new ARG boxes, located upstream or near the ectA-ectB, afsS, afsR, glnR, and redH genes, was tested by DNA band-shift assays. These data and those of previously assayed fragments permitted the construction of an improved model of the ArgR binding site. Interestingly, the overexpression of sporulation genes observed in the ΔargR mutant in our culture conditions correlated with a sporulation-like process, an uncommon phenotypeSIGrant BIO2013-34723 from the Spanish Ministry of Science and Innovation to PL. Work in the AM's laboratory was funded by the European Research Council (ERC Starting Grant; Strp-differentiation 280304) and by the Spanish Ministry of Economy and Competitiveness (Grant BIO2015-65709-R)

Transcriptomic analysis of Streptomyces coelicolor differentiation in solid sporulating cultures: first compartmentalized and second multinucleated mycelia have different and distinctive transcriptomes

[EN] Streptomycetes are very important industrial bacteria, which produce two thirds of all clinically relevant secondary metabolites. They have a complex developmental-cycle in which an early compartmentalized mycelium (MI) differentiates to a multinucleated mycelium (MII) that grows inside the culture medium (substrate mycelium) until it starts to growth into the air (aerial mycelium) and ends up forming spores. Streptomyces developmental studies have focused mainly on the later stages of MII differentiation (aerial mycelium and sporulation), with regulation of pre-sporulation stages (MI/MII transition) essentially unknown. This work represents the first study of the Streptomyces MI transcriptome, analyzing how it differs from the MII transcriptome. We have used a very conservative experimental approach to fractionate MI from MII and quantify gene expressions. The expression of well characterized key developmental/metabolic genes involved in bioactive compound production (actinorhodin, undecylprodigiosin, calcium-dependent antibiotic, cpk, geosmin) or hydrophobic cover formation-sporulation (bld, whi, wbl, rdl, chp, ram) was correlated with MII differentiation. Additionally, 122 genes conserved in the Streptomyces genus, whose biological function had not been previously characterized, were found to be differentially expressed (more than 4-fold) in MI or MII. These genes encoded for putative regulatory proteins (transcriptional regulators, kinases), as well as hypothetical proteins. Knowledge about differences between the MI (vegetative) and MII (reproductive) transcriptomes represents a huge advance in Streptomyces biology that will make future experiments possible aimed at characterizing the biochemical pathways controlling pre-sporulation developmental stages and activation of secondary metabolism in StreptomycesSIThis research was funded by grant BIO2010-16303 from the Subdirección General de Proyectos de Investigación, (DGI), Ministry of Science and Innovation (MICINN), Spain; and by an ERC Starting Grant (Strp-differentiation 280304). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Educafarma 10.0

Memoria ID-030. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2021-2022

EducaFarma 9.0

Memoria ID-020 Ayudas de la Universidad de Salamanca para la innovación docente, curso 2020-2021