Traditionally, the description of the developmental
cycle of streptomycetes focused on vegetative substrate
mycelium and aerial hyphae and spores. In frame of their
minireview, Yag€ue et al. outline a more refined view on
vegetative mycelium (MI) that suffers under stress –
including nutrient or oxygen limitation – programmed
cell death (PCD) and, subsequently, differentiates to segments
of multinucleated mycelium (MII). This process
facilitates rapid growth and nucleoid division and correlates
with the production of secondary metabolites. Prior
to sporulation, a second round of PCD occurs. Recent
studies revealed that these successive stages are general
features of many investigated Streptomyces species. Lamp
et al. discovered a novel spore protein MptS, which is a
unique metallophosphatase type from Streptomyces species.
The enzymatically active MptS accumulates within
spores, and it is required for their dormancy. Possibly,
inorganic phosphate released by MptS may interact with
abundant Ca2+ ions and thus trigger the formation of
calcium phosphate, contributing to the robustness of
spores. The presence of MptS was shown to be important
for the sensing process between Streptomyces spores with
Aspergillus conidiospores that provokes concerted
responses of both partners.