Figures (6)  Tables (1)

    • Figure 1. 

      Grafting affects anthocyanin accumulation in F/I combination. (a) Phenotype of grafted seedlings with differential grafting combinations (red arrows indicate the bonding sites of scion and rootstock, the black circle is the anthocyanin accumulation area) (F/F: Malus crabapple cv. 'Flame' as scion and Malus crabapple cv. 'Flame' as rootstock; F/I: Malus crabapple cv. 'Flame' as scion and Malus crabapple cv. 'Indian Magic' as rootstock; I/F: Malus crabapple cv. 'Indian Magic' as scion and Malus crabapple cv. 'Flame' as rootstock; I/I: Malus crabapple cv. 'Indian Magic' as scion and rootstock). (b) Paraffin section of the interface in non-grafted and grafted seedlings.

    • Figure 2. 

      Transcriptome analyses of stem of scions and rootstock in different grafting combinations. (a) Pearson correlation between samples (the horizontal and vertical coordinates of the graph are the square of the correlation coefficient of each sample). (b) Principal component analysis of samples.

    • Figure 3. 

      The number of differential expressed genes for compare group. The horizontal coordinate is the log2(foldchange) value, the vertical coordinate is −log10(padj) or −log10(pvalue), and the threshold line for the differential gene screening criteria.

    • Figure 4. 

      Functional analysis of differentially expressed genes between grafting combinations. (a) KEGG enrich analyses in F-I-S vs I-F-R, (b) KEGG enrich analyses in F-I-R vs I-I-R, (c) KEGG enrich analyses in I-F-S vs I-I-S, (d) GO enrich analyses in F-I-S vs I-F-R, (e) GO enrich analyses in F-I-R vs I-I-R, (f) GO enrich analyses in I-F-S vs I-I-S.

    • Figure 5. 

      Analysis of genes associated with anthocyanin biosynthesis during grafting. (a) Heatmap describing the expression of candidate transcription factors. (b) Relative expression levels of MdSAUR20 in F-I-S and I-F-R. (c) The content of anthocyanin in F/F vs F/I. (d) Schematic diagrams of the MdSAUR20 promoters. The error bars indicate the SD of three biological replicates. Asterisks indicate statistically significant differences (*p < 0.05; **p < 0.01) according to Student's t test.

    • Figure 6. 

      Functional assay of in MdSAUR20. (a) Pigmented transgenic cells were formed in seedling transformed with OE-MdSAUR20. Scale bar = 1 cm (b) Anthocyanin content in inoculated apple tissue culture seedlings. (c) Relative expression levels of MdSAUR20 in seedlings and anthocyanin biosynthesis genes. Data are presented as mean values ± SD of three independent biological replicates. Asterisks indicate significant difference by Student's t-test.

    • Sample
      name      		Clean reads% ≥ Q30Total readsMapped reads
      I-I-R-126,367,34093.2652,734,68045,507,642 (86.3%)
      I-I-R-222,928,73993.2145,857,47839,118,647 (85.3%)
      I-I-R-322,104,19193.9944,208,38238,710,947 (87.56%)
      I-I-S-123,790,35093.8947,580,70041,410,502 (87.03%)
      I-I-S-223,041,21693.2946,082,43240,172,269 (87.17%)
      I-I-S-323,120,81793.0046,241,63440,433,561 (87.44%)
      I-F-S-123,048,14094.0046,096,28040,314,380 (87.46%)
      I-F-S-222,692,49793.9045,384,99440,033,821 (88.21%)
      I-F-S-319,344,38793.0038,688,77433,125,491 (85.62%)
      I-F-R-122,931,22694.3745,862,45240,818,713 (89.0%)
      I-F-R-222,311,55293.0644,623,10438,436,230 (86.14%)
      I-F-R-322,713,77693.8445,427,55239,092,461 (86.05%)
      F-I-S-122,724,01894.1545,448,03640,037,863 (88.1%)
      F-I-S-223,260,09693.9346,520,19239,871,870 (85.71%)
      F-I-S-322,846,84194.0545,693,68240,535,794 (88.71%)
      F-I-R-123,151,62294.0646,303,24441,035,064 (88.62%)
      F-I-R-225,981,53694.1951,963,07245,465,386 (87.5%)
      F-I-R-323,629,46794.1947,258,93441,551,698 (87.92%)
      Clean reads: number of reads after raw data filtering; % ≥ Q30: Percentage of total bases with Phred values greater than 30; Total reads: number of clean reads of sequencing data after quality control; Mapped reads: number of reads matched to the genome and their percentages.

      Table 1. 

      RNA sequencing data.