Cell division is induced during early haustorium development.

Hairy root transformed with CYCB1;2 pro::YFP treated or not treated with 10 µM DMBQ. A to C. Transformed root without DMBQ treatment. YFP-fluorescing transgenic roots observed under bright field (A) or fluorescence (B) stereoscopy. In magnified view of root tip under fluorescence (C), roots were stained with 400 µg/ml propidium iodide (PI) to highlight root cell morphology. D to F. Transformed root after 24 h on DMBQ-containing agar (w/v 0.7%). Haustorium region in bright field (D) and under fluorescence (E) stereoscopy. PI-stained haustorium observed under fluorescence (F). The long arrows point to haustoria and the arrowheads to root tips. Red color indicates PI staining and green indicates GFP fluorescence. Yellow bar corresponds to 0.25 mm and white bar to 50 µm.