Fig. 5

Type-A and Type-B Response Regulators in Medicago truncatula. a-b Number of genes encoding RRBs (a) and RRAs (b), respectively, identified in the genome of A. thaliana, M. truncatula and V. vinifera. c Phylogenetic tree of RRs, based on full-length proteins from A. thaliana, M. truncatula and V. vinifera. Protein sequences were aligned with the Muscle algorithm and the phylogenic tree was built with the Seaview software package. Numbers indicate the probability for each branch. The tree was rooted on the ARR22 from A. thaliana [75]. Proteins labelled with a blue dot are non-canonical RRs. d Heat map of the expression pattern of M. truncatula genes encoding RR proteins. Data were retrieved from the M. truncatula Gene Expression Atlas Affymetrix microarray database (MtGEA; [68]) for various organs (right panels), from [69] for roots, nodules and nodule zones (middle panels), and from [60] for root epidermis expression and response to Nod factors (NF, right panels). Meristematic zone (ZI), distal and proximal differentiation/rhizobial infection zones (ZIId and ZIIp), inter-zone (IZ) and fixation zone (ZIII). Dashes indicate that there is no probe available on the Affymetrix M. truncatula chip [68]. The red/white color scale indicates log2 expression values for each heat map, which were normalized independently, with highest expression as red and lowest expression as white. A median was used as the central value and black boxes indicate that no probe was available on the microarray