## 2 Results
### Effects of ABA and NAA on Berry Development and Ripening
#### 2.1.2 Changes of Endogenous ABA and Auxin Biosynthesis and Signaling Pathway  
We then investigated the responses of endogenous ABA and auxin biosynthesis and signaling to ABA and NAA spraying. The levels of endogenous ABA and indole-3-acetic acid protein (IAA) in grape berries were measured at stages of E-L 33, E-L 34, E-L 35, and E-L 36 (Figure 2A). There was no significant difference in ABA and IAA concentration among all samples at E-L 33, before treatment application. The ABA concentration peaked at E-L 34 stage then decreased until ripening in the control group. In contrast, the concentration of ABA increased sharply at E-L 34 after ABA1000 and ABA800 application, while the ABA accumulation in NAA-treated samples was inhibited by NAA treatment. Both ABA treated and control samples were found to have their ABA peak at E-L 34, whereas the peak time was delayed to E-L 35 stage in NAA treated samples. Transcriptomic data of ABA1000, NAA100, and the control in 2015 showed that three VviNCEDs, which are  
Figure 1: Total soluble solids and tittatable acidity in two consecutive seasons. The different shape represents the phenological stage: square (E-L 33 stage), big circle (E-L 34 stage), triangle (E-L 35 stage), rhombus (E-L 36 stage), small circle (E-L 38 stage). The lines of green, light purple, purple and light green represent Control, 800 mg/L abscisic acid (ABA) (ABA800), 1000 mg/L ABA (ABA1000), and 100 mg/L synthetic auxin 1-naphthaleneacetic acid (NAA) (NAA100), respectively. Bars represent \(\pm\) standard deviation. involved in both norisoprenoid and ABA biosynthesis, were found to be up-regulated by ABA treatments at three different developmental stages, respectively (Figure 2B). On the contrary, the VviNCEDs were down-regulated by NAA treatment, especially at E-L 34 stage. It can explain the higher concentrations of ABA in ABA-treated berries while lower ABA levels in NAA-treated berries. Additionally, different from ABA, the concentration of IAA was very low in all samples. There was a decline of the IAA concentration at E-L 34 and then a small increase was found at the following stages. Generally, no differences were observed among treatments and control; however, a lower amount of IAA was found in ABA samples at E-L 36. We observed that ABA application suppressed the expression of the genes encoding tryptophan aminotransferase related 1 (TAR1, VIT_200s0225g00230) and YUC flavin monooxygenase 10 (YUC10, VIT_207s0104g01260) at E-L 35 and E-L38 stages, respectively (Figure 2C). The VviTAR1, VviTAR3, and VviYUC10 also showed low levels in NAA-treated berries at E-L 34, E-L 36, and E-L38 stages, respectively. The VviYUC6 (VIT_204s0023g01480) was markedly up-regulated by NAA treatment at E-L 36 stage. A heatmap displaying the regulation of ABA and auxin signal transduction pathway by exogenous ABA and NAA is reported in Figure 3. In the ABA signaling pathway, the binding of ABA with the PYR/PYL receptor inhibits the protein serine/threonine phosphatase 2C (PP2C), which inhibits the kinase SnRK2 by its phosphatase activity [22]. The SnRK2s released from the PP2 Cs inhibition can activate the downstream ABA-responsive element binding factors (ABFs), leading to the activation of ABA-responsive genes [23]. In ABA-treated berries, the expression of ABA receptor gene VviPYR/PYL was unchanged in comparison to the control, and one VviABF (VIT_208s0007g03420) was up-regulated at E-L 34 stage. Unexpectedly, the transcript abundance of five VviPP2 Cs (VIT_202s0025g01390, VIT_206s0004g05460, VIT_216s0050g02680, VIT_206s0004g06840, and VIT_216s0022g02210) was significantly increased at E-L 34, E-L 35, or E-L 36 stages (Figure 3).