Down-regulation of MtEPP1 negatively affects nodule formation. (A) Number of transgenic roots showing nodules or NF-induced branched root hairs (C). (B) Number of nodules per plant. (D) Number of NF-induced deformed root hairs per centimeter of roots. Box plots represent the first and third quartile (horizontal box sides), and the minimum and maximum (outside whiskers). An asterisk indicates a significant difference according to one-way ANOVA (P-value <0.001). Data shown were obtained from 10 biological replicates each one containing 20 different composite M. truncatula plants.