Carbohydrate content (mg/g FW)

1. A Carbohydrate content (mg/g FW) B isa1- isa2- P4F8 P4F1 WT isa1- host isa1- isa2- host WT isa1- isa2- isa1- AtISA1 (P6C3) AtISA1 (P1D1) AtISA1 (P1A4) ZmISA1 (P7E5) ZmISA1 (P7E4) ZmISA1 (P2D7) ZmISA1 (P4F8) ZmISA1 (P4F1) ZmISA1 (P4F5) ZmISA1 (P4D3) P1D1 P4D3 P7E4 P4F5 P6C3 P1A4 P7E5 P2D7 Scale bars = 10 µm

2. Supplemental Figure S5: Panel A: starch and WSP contents determined in host and transgenic lines (as indicated in the figure). Contents are expressed in mg of carbohydrate per g of fresh weight (FW) and are the means of three independent biological replicates. Black and grey vertical bars indicate starch and WSP content respectively. Vertical lines on bars stand for standard error. Typically no or very low amount of WSP were detected for WT (Wild Type) and transgenic lines expressing AtISA1 or ZmISA1 protein. Panel B: scanning electron microscopy images of purified starch granules (host and transgenic lines are indicated). The starch samples were prepared from Arabidopsis leaves harvested at the end of the illuminated period (16h light / 8h dark). Scale bars = 10µm. Note that some transformants were not complementing although they were hygromycin resistant: P7E5 (isa1- exp. ZmISA1) and P4F1 (isa1- isa2- exp. ZmISA1). Rearrangement of the transgene may have occurred during integration into the nuclear genome of the plant leading to an alteration of the ZmISA1 open reading frame and consequently of its expression.