Figure 7.

GLV gof and lof root phenotypes. A, Representative GLV^OE lines grown on inclined plates showing increasing defects in root gravitropic growth. B, Gravitropic response of GLV^OE lines following gravistimulation. Stars indicate significant differences compared with the wild type (wt; for odds ratio estimates of root tip angle distribution, see Supplemental Table S5). C, Quantification of the GLV^OE root growth phenotype according to the GI ± se (n = 17–45). For clarity, the results for only one of two analyzed independent lines are shown (for details, see “Materials and Methods”). D, Representative GLV^OE root tips. Arrowheads show the boundary between the root meristem and the elongation zone. E, Quantification of root meristem size (μm) in GLV^OE lines ± se (n = 14–84). For clarity, only one of two analyzed independent lines is shown. F, GI quantification of GLV lof mutants roots ± se (n = 25–30). G, GI quantification of wild-type roots treated with GLV-derived synthetic peptides ± se (n = 6–8), as shown in H and I. H and I, Root growth defects induced by GLV synthetic peptides. Wild-type roots were treated with either unmodified peptides at 10 μm (H) or 100 nm (I, bottom panel) or Tyr-sulfated peptides (Y*) at 100 nm (I, top panel). As indicated at the top of C, E, and F, GLV genes or peptides were grouped according to their expression domains within the root: I, columella/QC; II, meristem; III, maturation zone. n.e., Not expressed in the main root; np, no-peptide treatment; rGLVp, random GLVp. Stars indicate significant differences compared with the wild type (*P < 0.05, **P < 0.01, ***P < 0.001). Bars = 0.5 cm (A, H, and I) and 50 μm (D).