Extended Data Fig. 2: TOP1α controls root gravitropism in response to sucrose.

a, b, Root gravitropism (a) and statistical analysis of vertical growth index (VGI) (b) in roots of the indicated genotypes under ±Suc treatment. Data were analyzed from 15 seedlings for each treatment from 3 experiments. Statistical significance was determined by Student’s t-test (two-tailed) (b) and are expressed as mean ± s.d. Scale bar: 1 cm. c, Graphical representation of VGI to define root gravitropism. d, Time course of the gravity response and amyloplast formation in WT and top1α ± Suc treatment. Seedlings were turned 90° from the vertical axis and fixed at the indicated time points. Amyloplast formation and levels in layers S1 and S2 were examined. Yellow lines represent amyloplast levels. Green arrows mark amyloplasts in premature CSCs. (m/n) indicates m in n of biological repeats showing the displayed features. Scale bar: 25 µm. e, f, Root gravity response (e) and statistical analysis (f) of WT and top1α in response to Suc. Data represent mean ± s.d. of 3 biological repeats. Statistical significance was determined by Student’s t-test (two-tailed) (f) and are expressed as mean ± s.d. Scale bar: 0.5 mm. (m/n) in (d and e) indicates m in n of biological repeats showing the displayed features.