Microscopic analysis of β-glucuronidase (GUS) expression patterns in root-knot nematode (RKN)-infected tomato roots harboring the SlWRKY3 and SlWRKY35 promoter–GUS fusion constructs. (A–H) Micrographs of SlWRKY3::GUS reporter line. (A) Noninoculated root harboring the WRKY3:GUS fusion construct exhibited no GUS signal in root tip or elongation zone. (B) Infected roots at 2 dai. (C) Noninoculated roots at 5 days. (D) Infected roots at 5 dai. (E) Noninoculated roots at 15 days. (F) Developing galls in infected roots at 15 dai. (G) Noninoculated roots at 28 days. (H) Mature galls in infected roots at 28 dai. (I–P) Micrographs of SlWRKY35:GUS reporter line. (A) Noninoculated root harboring the WRKY35:GUS fusion, exhibiting no GUS signal in root tip or elongation zone. (B) Infected roots at 2 dai. (C) Noninoculated roots at 5 days. (D) Infected roots at 5 dai. (E) Noninoculated roots at 15 days. (F) Developing galls in infected roots at 15 dai. (G) Noninoculated roots at 28 days. (H) Mature galls in infected roots at 28 dai. Arrows indicate nematodes. (A–E, G, I–L): micrographs as viewed under light microscope. (F, H, M–P): bright-field image of galls photographed through a stereomicroscope. Bars: (A–E, G, I–L) 50 μm; (F, H, M–P) 500 μm.