New paper from Gutjahr lab.

Control of arbuscular mycorrhiza development by nutrient signals.

Samy Carbonnel and Caroline Gutjahr

In summary, the mechanisms of how AM development is controlled by nutrient signaling are yet elusive. However, circumstantial evidence suggests that control occurs at multiple levels, and includes nutrient, phytohormone and symbiosis as well as systemic and cell-autonomous signaling. The signal operating in systemic shoot-to-root Pi signalling remains to be found. However, strigolactone exudation, the DELLA/GA signalling module and the P1BS element-binding transcription factor are excellent candidates for local mediators between nutrient status and AM development. Additionally, the co-occurrence of MYCS and P1BS cis-elements in AM-inducible promoters strongly suggests that Pi starvation signaling and AM signaling are required simultaneously for symbiotic gene expression and consequently colonization (Figure 1D). Transgenic manipulation using dominant negative and dominant active candidate signaling components with the aim to restore AM development at sufficient Pi should help to pinpoint the important regulators and to detangle how plants integrate symbiosis, phytohormone and nutrient signaling to control AM development in function of their nutrient status.