Bacterial spore germination receptors are nutrient-gated ion channels

Bacterial spores resist antibiotics and sterilization and can remain metabolically inactive for decades, but they can rapidly germinate and resume growth in response to nutrients. Broadly conserved receptors embedded in the spore membrane detect nutrients, but how spores transduce these signals remains unclear. Here, we found that these receptors form oligomeric membrane channels. Mutations predicted to widen the channel initiated germination in the absence of nutrients, whereas those that narrow it prevented ion release and germination in response to nutrients. Expressing receptors with widened channels during vegetative growth caused loss of membrane potential and cell death, whereas the addition of germinants to cells expressing wild-type receptors triggered membrane depolarization. Therefore, germinant receptors act as nutrient-gated ion channels such that ion release initiates exit from dormancy.

Automated summary

Bacterial spores can stay dormant for long periods of time, but can quickly germinate and resume growth when nutrients are available. Receptors in the spore membrane act as nutrient-gated ion channels, initiating germination and exit from dormancy. Mutations that widen the channels induce germination in the absence of nutrients, while narrowing the channels prevents ion release and germination in response to nutrients.