Morphological Development and Secondary Metabolism in Streptomyces Species

Streptomyces species are filamentous soil bacteria renowned for their complex life cycle and prolific production of specialised metabolites, including many clinically important antibiotics. Their developmental programme involves an ordered sequence of morphological changes: germination of spores, substrate mycelium expansion, aerial hyphae formation and sporulation. These stages are tightly coupled to the activation or repression of secondary metabolite biosynthetic gene clusters. Central to this coordination are regulatory proteins such as sigma factors, transcriptional regulators, nucleoid-associated proteins and even phage‐related elements that influence both cell differentiation and metabolite output. Understanding how these components interconnect offers insight into fundamental bacterial biology and informs strategies to discover or enhance the production of novel bioactive compounds.

Research from Nature Portfolio

Recent studies have revealed that a phage tail-like apparatus produced by Streptomyces coelicolor plays an intrinsic role in its developmental life cycle. These extracellular contractile injection systems assemble during vegetative growth, and mutants lacking this machinery show delayed onset of aerial hyphae and reduced programmed cell death, demonstrating that such structures modulate the transition to sporulation rather than merely serving defensive functions. In parallel, investigation of the extracytoplasmic function sigma factor σE in S. coelicolor has shown that it can act both as an activator and a repressor of transcription. This dual functionality reshapes our view of sigma factors, revealing that σE directly interacts with promoter regions to fine-tune genes implicated in envelope integrity, spore formation and the onset of secondary metabolism. Together, these findings highlight non-canonical regulators that bridge morphological development and metabolic switching.

Morphological Development and Secondary Metabolism in Streptomyces Species publication trend

The graph below shows the total number of articles in morphological development and secondary metabolism in streptomyces species across all publications each year (not limited to Nature Index journals).

Technical terms

Extracellular contractile injection system (eCIS): A phage‐tail-like apparatus produced by bacteria that can influence host development and intercellular interactions.

Extracytoplasmic function sigma factor (σE): An alternative sigma factor that directs RNA polymerase to specific promoters, modulating cell envelope stress responses and developmental gene expression.

Nucleoid-associated proteins (NAPs): DNA-binding proteins that shape chromosomal architecture and regulate global gene transcription.

Sporulation: The developmental process by which aerial hyphae septate and differentiate into resistant spores.

Secondary metabolism: Biosynthetic activities that produce non-essential specialised metabolites, such as antibiotics and signalling molecules.

References

1. A contractile injection system is required for developmentally regulated cell death in Streptomyces coelicolor. Nature Communications (2023).
2. σE of Streptomyces coelicolor can function both as a direct activator or repressor of transcription. Communications Biology (2024).
3. Prophage induction can facilitate the in vitro dispersal of multicellular Streptomyces structures. PLOS Biology (2024).
4. Redefining development in Streptomyces venezuelae: integrating exploration into the classical sporulating life cycle. mBio (2024).
5. The role of two major nucleoid-associated proteins in Streptomyces, HupA and HupS, in stress survival and gene expression regulation. Microbial Cell Factories (2024).