Review: Nuclear Ca2+ signaling in endosymbiosis

The Common Symbiosis Signaling Pathway (CSSP) conveys the perception of endosymbionts (rhizobia or mycorrhizal fungi) at the plasma membrane to the nucleus to initiate transcriptional responses. Calcium oscillations are core to the CSSP, whether the endosymbiont is fungal or bacterial. Barker et al. review the molecular players involved in the CSSP, with a focus on ongoing efforts to understand the contribution of calcium oscillations. They also describe new evidence that a third symbiotic partnership, that between Frankia bacteria and their actinorhizal plant partners, depends on the CSSP. New Phytol. 10.1111/nph.14350