## 3 Results
### Expression Modes of Genes Related to Anthocyanin Synthesis by Different Hormone Treatments
GA treatment reduced the expression levels of anthocyanin synthesis related genes to some extent, but GA treatment significantly enhanced the expression levels of _VvPAL_, _Vv4 CL_, _VvC4H_, _VvF3'H_, _VvUFIGT_, and _VvLDOX_ in the middle of color conversion (14 DAT), which indicates that GA is mainly involved in the formation of berry color in the middle stages of color conversion. ABA and MeJA treatments significantly upregulated the expression of anthocyanin structural genes in the early color-change period (7 DAT-14 DAT). After exogenous ABA and MeJA treatment, the expression levels of most anthocyanin structural genes reached the maximum at 7 DAT and 14 DAT, and the expression of anthocyanin structural genes was higher in ABA treatment than in MeJA treatment. Furthermore, we found that NAA treatment generally downregulated the expression level of anthocyanin structural genes and delayed the peak expression of anthocyanin structural genes to 35 DAT, indicating that NAA inhibits the expression level of anthocyanin structural genes and is mainly involved in the formation of berry color in the mature stage (Figure 7). Figure 7: Expression modes of genes related to anthocyanin synthesis by different hormone treatments. (**A**) Anthocyanin metabolism pathway. (**B**) The expression of anthocyanin-related genes by different hormone treatments. Interaction Mode Variation of VvmiR156b/c/d-VvSPL9 Modules in Response to Hormone Signal in the Regulation of the Grape Color Formation  
By comparing the expression levels of VvmiR156b/c/d-VvSPL9 and anthocyanin synthesis-related genes (Figure S3), we found that during grape berry development, the expression patterns of VvmiR156b/c/d were positively correlated with the expression patterns of anthocyanin synthesis-related genes. Among them, the expression of VvmiR156c/d had a significant positive correlation with the expression of anthocyanin synthesis-related genes including _VvPAL_, _Vv4 CL_, _VvCHS_, _VvCHI_, _VvF3'H_, _VvF3'5H_, _VvDFR_, _VvUFGT_, and _VvOMT_ (r = 0.6352\(\sim\)0.9963), while the correlation between VvmiR156b and anthocyanin synthesis-related genes is poor. VvmiR156b was only positively correlated with _VvLDOX_ and _VvUFGT_ (r = 0.3451\(\sim\)\(-\)0.4372), but _VvSPL9_ was negatively correlated with the expression of anthocyanin synthesis-related genes including _VvPAL_, _VvF3'H_, _VvF3'5'H_, _VvLDOX_, and _VvUFGT_ (r = \(-\)0.3352\(\sim\)\(-\)0.6396). GA and ABA treatment enhanced the positive correlation between VvmiR156b/ and _VvPAL_, _VvC4H_, _Vv4 CL_, boosted the positive correlation between VvmiR156c/d and _VvC4H_, _VvLDOX_, and weakened the positive correlation between VvmiR156c/d and _VvCHS_, _VvCHI_, _VvDFR_, _VvUFGT_. While GA treatment enhanced the negative correlation between _VvSPL9_, _VvPAL_, _VvCHI_, and _VvUFGT_. In addition, ABA treatment significantly boosted the positive correlation between VvmiR156b, _VvF3'H_, _VvF3'5H_, _VvLDOX_, and _VvUFGT_ (r = 0.8592\(\sim\)0.9423), while MeJA enhanced the positive correlation between VvmiR156b and _VvC4L_, _VvF3'H_, _VvF3'5'H_, and boosted the positive correlation between VvmiR156c/d and _VvDFR_. NAA promoted the positive correlation between VvmiR156b and _VvDFR_ and between VvmiR156c/d and _VvLDOX_, _VvUFGT_, while the negative correlation between _VvSPL9_ and _VvDFR_ was enhanced by NAA treatment. In summary, the correlation analysis of temporal and spatial expression showed that VvmiR156b/c/d can negatively regulate _VvSPL9_ expression by responding to different hormone signals, modulated the expression levels of genes related to anthocyanin synthesis, and thereby participated in the formation of grape color.