FIG 2.

Time course analysis of TuMV-induced membranous aggregates in N. benthamiana leaf midrib. (A) An upper young leaf of an N. benthamiana plant was imaged by tile scanning with a Zeiss LSM-780 confocal microscope using a 10× objective. The tile scan was carried out by assembling images of 11 by 13 tiles. (B) Cross sections of a leaf midrib area systemically infected with TuMV/6K₂:GFP (marked with a rectangle in panel A) were imaged by confocal microscopy using a 20× objective on the day postinfection indicated in the upper right. The Fluorescent Brightener 28-stained cell wall is shown in false magenta color. 6K₂:GFP is shown in green. All images are single optical slices. (C to E) Time course analysis of TuMV-induced membranous aggregates in vascular parenchymal cells. N. benthamiana leaf midribs systemically infected with TuMV/6K₂:GFP were chemically fixed, processed, and observed by TEM. The lower panels show higher-magnification images of the areas in the rectangles in the upper panels. (C) TuMV-induced CM structures, which were associated with SMVL structures, were located close to the rER in a vascular parenchymal cell at 5 dpi. (D) TuMV-induced heterogeneous SMVL structures in a vascular parenchymal cell at 6 dpi. (E) TuMV-induced aggregates contain both SMVL structures and DMVL structures with an electron-dense core in a vascular parenchymal cell at 7 dpi. Ue, upper epidermis; Le, lower epidermis; Ac, angular collenchyma cells; Vt, vascular tissue; Me, mesophyll cells; N, nucleus; G, Golgi apparatus; M, mitochondrion; V, vacuole; CL, chloroplast; CW, cell wall; rER, rough endoplasmic reticulum; CI, cytoplasmic inclusion body; CM, convoluted membranes; SMVL, single-membrane vesicle-like structure; DMVL, double-membrane vesicle-like structure.