Down-regulation of MtEPP1 reduces the activation of early nodulin genes. (A) Down-regulation of MtEPP1 strongly decreased the MtENOD11-induced expression as revealed by pMtENOD11-gusA histochemical assay and (B) by qRT-PCR in response to NF. NF-triggered expression of MtERN1 (C), MtNF-YB1 (D), MtNIN (E) and MtENOD40 (F) was almost abolished in MtEPP1-silenced transgenic roots. Box plots represent the first and third quartile (horizontal box sides), and the minimum and maximum (outside whiskers). Data shown were obtained from four independent biological replicates. One-way ANOVA followed by a Tukey honest significant difference (HSD) test was performed (P-value <0.01). Statistical classes sharing a letter are not significantly different.