Fig. 1.

Multiple sequence alignment of PIP sequences from Q. macrocarpa, A. thaliana, and P. tremula×P. tremuloides. Predicted amino acid sequences were aligned using ClustalW. Identical residues in all sequences are shaded in black, while similar residues are shaded in grey. The conserved NPA motives are shaded in green. The ar/R selectivity filter residues are shaded in magenta. Histidine residues involved in pH sensing are shaded in blue. Predicted transmembrane helices are shown in brown boxes.