(A) The expression of Nfre:GUS in hairy root of WT without Rhizobium inoculation. (B) The expression of pNfre:GUS in hairy root of WT at 3 weeks after inoculation with M.loti (C) The expression of pNfre:tYFPnls is maintained in the root hairs at 3 weeks after inoculation with M.loti. (D) The epidermal cells, primarily localized in the root susceptible zone, show activity of the Nfre promoter visualized by the nuclear localized triple YFP protein (tYFPnls). (E) Widespread activity of the Nfr1 promoter in the uninoculated root visualized by nuclear localized triple YFP protein (tYFPnls). (F) Transcript levels of Nod factor receptors measured by quantitative RT-PCR in Mock (water)-treated, Nod factor-treated or M. loti inoculated wild type roots. Relative expression levels of the three receptors in three biological and three technical replicas are shown. The levels of housekeeping genes, ATP, UBC and PP2A were used for calculating the relative expressions. *p<0.05, Student´s t-test compared with the expression level in Mock (water)-treated samples. (G) The epidermal cells (root hairs- arrows) of 3dpi root show activity of the Nfre promoter (Nfre:tYFPnls). (H) The epidermal cells (root hairs- arrows) of 3dpi root show lower activity of the Nfr1 promoter (Nfr1:tYFPnls) when compared to the rest of cortical cells or with Nfre in (G). Scale bars, 40 µm (A, B), 50 µm (C), 1 mm (d, e), 100 µm (G, H).