Extended Data Fig. 8: TOP1α and TOR regulate PLT2 expression.

a, b, Gene expression (a) and protein distribution of SHR, SCR, and PLT1 in plants (b) of the indicated genotypes. Gene expression in WT –Suc was set to 1. Data represent mean ± s.d. of 3 biological repeats. Student’s t test (two-tailed). (m/n) indicates m in n of biological repeats showing the displayed features. Scale bars: 50 µm. c, Diagram of the PLT2 locus. Gray and black rectangles and black lines represent untranslated regions, coding regions, and introns, respectively. A DNA fragment (shown in red) was deleted in the plt2 mutant. d, Quantification of CC number in plants of the indicated genotypes. Data were analyzed from 15 seedlings for each genotype from 3 experiments. Statistical significance was determined by one-way ANOVA and Tukey test (P < 0.05) (see Supplementary Data 1 for specific P values). e, Root gravity responses and amyloplast formation in top1α and top1α plt2 plants of the indicated genotypes. 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, white arrow marks amyloplasts and green arrows mark the premature CSC indicating that plt2 mutation failed to rescue the QC quiescence. (m/n) indicates m in n of biological repeats showing the displayed features. Scale bars: 25 µm. f, Diagram of the SS1/2/3/4 and CYCD5;1 loci. Gray and black rectangles and black lines represent untranslated regions, coding regions, and introns, respectively. The regions tested by ChIP are marked by black lines. g, RT-qPCR of SS1-4 in Ler and top1a plants under the indicated treatment. Gene expression in WT was set to 1. Data represent mean ± s.d. of 3 biological repeats. Statistical significance was determined by one-way ANOVA and Tukey test (P < 0.05) (see Supplementary Data 1 for specific P values).