Figure 3.

Model for the negative regulation of rhizobial infection and nodule number in L. japonicus. In response to rhizobial infection, NIN activates the CLE-RS1/2> HAR1> TML signaling pathway²² to suppress infection threads (ITs) formation and nodule number (blue lines). The nitrate-induced NRSYM1> CLE-RS2> HAR1 signaling pathway could negatively regulate nodule number by using unknown downstream factors other than TML. In the presence of nitrate NRSYM1 also controls IT formation locally in the root through a mechanism independent of AON pathway (red lines).