Immunodominant membrane proteins (IDPs) of phytoplasma were classified into three distinct types. (a) Gene organizations around the genes encoding three IDPs. The gene organization of types 1, 2 and 3 were described using sequence from SPWB (U15224), WX (AF533231) and OY‐W (AB124806), respectively. (b) Schematic representation of the putative translocation products of three IDPs. Transmembrane regions are shown as blue regions and non‐transmembrane regions are shown as pink regions. The N‐terminal transmembrane region of Amp (type 3) is cleaved during protein localization (Kakizawa et al., 2004), and the cleavage site is indicated with a filled triangle. Abbreviations: C, C terminus; N, N terminus; aa, amino acids. (c) Schematic representation of the hypothetical transmembrane structures of three types of IDP. Abbreviations and colour lines are same as B.