(A) Confocal images showing expression of the marker for the primordial cells pDR4:NLS-3xYFP and the founder cell marker pSKP2Bs:NLS-3xmCherry at the base of emerged LRs. (B) Left, cartoon illustrating experiment. Right) Bright field images showing formation of new LRs after excision of emerged LRs. Black arrows: sites of emergence. (C-D) Confocal images showing expression of (C) pDR4:NLS-3xYFP or (D) pCBF3:NLS-3xmCherry in 4 dpi roots treated with 1μM acivicin or 1μM acivicin and 20 μM camalexin for 2 days. Acivicin is a camalexin biosynthesis inhibitor. Green/cyan arrows: central/lateral LRP regions, respectively. (E) Acivin and camalexin regulate LRP formation. Left, cartoon illustrating experiment. Right, quantification of LRP stages following treatments. *: p-value < 0.05 by ANOVA and Bonferroni tests. n≥20 roots/condition. (A-C, D) Scale bars: 25 μm (A,C,D) and 125 μm (B).