## 1 Introduction  
Grape berry ripening is an extremely complex physiological and biochemical process, accompanied by the formation of fruit color, flavor, and aroma. Among them, the color of grape berry is an important indicator of fruit quality. As grapes color, sugar and aroma accumulate in the berries. Therefore, the berry color and its related qualities above-mentioned directly affect its price and market competitiveness. Anthocyanin is the main pigment in grapes including cyanidin, delphinidin, peonidin, petunidin, and malvidin. Fruit color development is a very complex metabolic process, which is not only affected by genotype, climatic conditions, and cultivation techniques, but also by plant hormones. In the process of fruit coloring, plant hormones are key regulators and play important roles. A variety of hormones interact to co-regulate the formation of colors such as abscisic acid (ABA), gibberellin (GA), ethylene (ETH), auxin (AUX), and jasmonic acid (JA). The application of exogenous hormones can cause changes in endogenous hormones modulating the color formation. For example, ABA, ETH, and JA treatments promote fruit coloring and ripening; conversely, AUX applications inhibit the corresponding processes [1; 2; 3; 4]. Therefore, the effect and regulation mechanism of plant hormones on plant color has always been a hotspot of research. MicroRNAs (miRNAs), widely distributed in plants, are very important non-coding RNA regulators with a length of 19-24 nucleotides (nt). They play critical roles in plant growth and development, signal transduction, and the response to stress, mainly via their action in causing either complementarity-dependent cleavage or translational inhibition of the target mRNA molecules at the post-transcriptional level [5; 6]. In recent years, more and more reports have shown that miRNAs and their target genes are involved in the regulation of anthocyanin synthesis in plants. In plants such as _Arabidopsis thaliana_, tomato, apple, and grape, miR828 regulates the accumulation of anthocyanin and flavonoid by targeting MYB transcription factors such as _PAP1/MYB75_, _PAP2/MYB90_, and _MYB113_[7; 8; 9; 10; 11; 12; 13]; similarly, miR778 and miR827 also regulate these processes through the action of target gene _NLA_[14; 15]; and miR858 and target gene _MYB12_ are also involved in the regulation of anthocyanin biosynthesis [16; 17; 18]. Furthermore, multiple studies have reported that miR156 participates in the modulation of anthocyanin synthesis, which has been a hot topic for many researchers on anthocyanin synthesis [19; 20; 21]. In _Arabidopsis thaliana_, miR156 regulates anthocyanin synthesis by negatively regulating target gene _SPL_ through interacting with the _PAP1_ protein; _SPL9_ affects the transcriptional activation activity of the MYB-BHLH-WD40 complex, which inhibits the expression of anthocyanin synthesis _ANS_ and _DFR genes_, and thus decreases the accumulation of anthocyanin [22]. Under stress conditions, the biosynthesis of anthocyanin increases, and miR156-_SPL9_ may directly manipulate anthocyanin biosynthesis through _PAP1_ and _DFR_, while plants can mediate anthocyanin metabolism through miR156-_SPL8-DFR_ pathways [23]. In Iitchi (_Litchi chinensis_ Sonn. ), miR156a is inversely correlated with the expression profiles of its target genes _LcSPL1/2_ and _LcCHI_, and the increased expression of miR156a decreases the transcription level of _LCSPL1_, which downregulates anthocyanin biosynthesis via interaction with _LcMYB1_[24]. All these findings demonstrate that miR156s and their targets are involved in the modulation of color formation. However, up until now, little is known about how miR156s responds to hormones to mediate their targets involving the modulation of color formation. In our previous study, we confirmed that VvSPL9 is the target gene of VvmiR156b/c/d, which is involved in the regulation of grape berry development and maturation; and miR156s could be in response to gibberellin [25; 26; 27].