Figure 4.

Effect of ES4 on Intracellular Compartments.

(A) to (D) Transmission electron microscopy images of MVBs in 5-d-old Col-0 seedlings after 2 h mock (A) and 41 µM ES4 (B) treatment and quantification of the number (C) and size (D) of MVBs. Asterisks indicate GA, arrows point at the rough ER, and arrowheads mark the PVC/MVBs. Values represent means ± sd of MVBs number per cell in two (mock) or three (ES4 treatment) roots. In total, MVBs were counted in 39 epidermal and cortex cells for mock and 46 cells for ES4 (C). Values represent means ± sd of the PVC/MVBs size measured in 12 epidermal and cortex root cells for mock and 21 cells for ES4 (D). After ES4 treatment, the size of MVBs increased compared with the control (two-tailed Student’s t test, *P < 0.05) (D), whereas there was no significant difference in MVBs number per cell between ES4 treatment and control (two-tailed Mann-Whitney U test, P > 0.05) (C). Bars = 0.5 µm.

(E) to (L) Intracellular localization of CLC-GFP ([E] and [F]), GNL1-YFP ([G] and [H]), N-ST-GFP ([I] and [J]), and VHAa1-GFP ([K] and [L]) after mock ([E], [G], [I], and [K]) and 17 µM ([F], [H], and [J]) or 41 µM (L) ES4 treatment in 5-d-old seedlings. After 2 h of ES4 treatment, all markers displayed increased intracellular agglomerations. Bars = 10 µm.

(M) to (R) Intracellular localization of actin filament marker GFP-FABD ([M] to [O]) and microtubule marker GFP-MAP4 ([P] to [R]) after 2 h of mock, 83 µM ES4, or 2 mM H₂O₂ treatment. There was no visible effect of ES4 on actin filaments or microtubule markers, as it was observed after H₂O₂ treatments. Bars = 10 µm.