Fig. 5

TCPs rhythmically control translation and energy metabolism during fiber growth. a Schematic illustration of the strategy for predicting fiber cell-specific k-mer motifs. First, count the k-mer motifs that appear in each ATAC-seq peaks and then use the positional relationship between ATAC-seq peaks and target genes to determine the relationship between k-mer motifs and targeting genes. Finally, count the overall impact of k-mer motifs on their targeting genes. b The clustering (left) and target gene expression distribution (right) for the two groups of fiber cell-specific 8-mer motifs. See also Additional file 10: Table S9. c The statistical significance for the fiber cell-specific k-mer motifs in M1 (left) and M2 (right). The x- and y-axis denote the observed/expected ratios (Obs./Exp.) of C3 maximum expressed genes and values of significance test (Fisher’s exact test), respectively. Dashed lines denote the thresholds (Obs./Exp. > 1.5 or < 0.67, p-value < 0.05). d The sequence alignment and logos for TCP and TCP-like motifs. e The pie chart shows the proportion of TCP and TCP-like motifs targeting genes in the genes with the highest expression in C3. f Enriched GO-terms for TCP (left) and TCP-like (right) motif targeting genes. g Gel shift assay showing GhTCP14a binds with both TCP and TCP-like motifs. h The qRT-PCR validations for the rhythmic expressions of GhTCP14a under normal day-night (day/night) and continuous light (day/day) conditions. i The rhythmic expressions (RNA-seq) of two gene examples involved in protein translation and energy supply. The ATAC-seq signals (left) and diurnal RNA-seq (right) were shown. The green and red lines below the tracks of ATAC-seq denote the locations of TCP and TCP-like motifs, respectively. The width of the lines reflects the number of motifs. j The ribosome profiling assays for the OI protoplasts of WT ovules at 2 DPA show the day-night cycle of protein translation in fiber cells. k The quantifications of ATP concentration for WT ovules at 0, 1, and 2 DPA show the day-night cycle of energy status in fiber cells. Asterisks denote a significant difference (unpaired Student’s t test, ***P < 0.001)