Distribution of wheat PDI family proteins in the mature aleurone cells and the protein matrix of wheat grains. Cross sections of mature grains were immunostained with sera against TaPDIL1Aα (A, F, K), TaPDIL2 (B, G, L), TaPDIL3A (C, H, M), TaPDIL4D (D, I, N), or TaPDIL5A (E, J, O). Specimens were observed with a fluorescence microscope BZ-9000 (A-E, K-O) and a Confocal Imaging System FV1200 (F-J). Visible light images (gray) collected simultaneously are shown in the middle panels (F-O). Merged fluorescent and visible light images are also shown in the right panels (F-O). a, aleurone layer; pc, pericarp; pm, protein matrix; se, starchy endosperm. Arrowheads indicate aleurone grains. White dotted lines show the profile of one aleurone cell. Asterisks indicate A-type starch granules. Scale bars in A-E = 250 μm. Scale bars in F-J = 5 μm. Scale bars in K-O = 50 μm.