Fig. 1

Phylogenetic analysis and structural features of the TIP subfamily in tigernut, rice and Arabidopsis. a Shown is an unrooted phylogenetic tree resulting from full-length TIPs with MEGA6 (maximum likelihood method and bootstrap of 1,000 replicates), where the distance scale denotes the number of amino acid substitutions per site and the name of each group is indicated next to the corresponding clade. b Shown are the exon-intron structures. 0 and 1 indicate intron phases. c Shown is the distribution of conserved motifs among TIPs, where different motifs are represented by different color blocks as indicated and the same color block in different proteins indicates a certain motif. d Shown are the conserved residues such as dual NPA motifs and Ar/R selectivity filter. Unusual residues are marked in red. (At Arabidopsis thaliana, Ar/R aromatic/arginine, bp base pair, Ce Cyperus esculentus, H2 transmembrane helix 2, H5 transmembrane helix 5, LB loop B, LE loop E, NPA Asn-Pro-Ala, Os Oryza sativa, TIP tonoplast intrinsic protein)