Calcium signaling and transcriptional regulation in arbuscular mycorrhizal symbiosis

The establishment of the arbuscular mycor rhizal (AM) symbiosis requires a complex chemical crosstalk between the plant host and its fungal partner. Plant roots release strigolactones into the rhizosphere, which induce fungal spore germination and hyphal branching. In exchange, AM fungi (AMF) release chitooligosaccharides (COs) and lipo chitooligosaccharides (LCOs), signaling molecules that are recognized at the plant plasma membrane (Gough and Bécard, 2016). The recognition of AM fungi induces a chain of signaling events, resulting in the extensive transcriptional reprogramming of the host cell and the promotion of fungal colonization of the root. The core to this signaling process is required for both nodu lation and mycorrhization, and this has become known as the common symbiosis signaling pathway (CSSP or Sym pathway; Kistner and Parniske, 2002). A central component of the Sym path way is …