## 3 Results
### Expression of Genes in LOX-HPL Pathway  
C6 alcohol/aldehyde were considered to be characteristic compounds of non-muscat grape varieties such as Cabernet Sauvignon, Monastrell, and Tempranillo [42]. Based on previous studies, it was discovered that the LOX-HPL pathway controls the synthesis of C6/C9 compounds [43], so six key genes (_VvLOXA_, _VvLOXC_, _VvHPL1_, _VvADH1_, _VvADH2_ and _VvAAT_) were chosen to perform fluorescence quantitative PCR. In 2019, 1103P significantly up-regulated _VvLOXA_, _VvHPL1_, _VvADH1_, _VvADH2_, and _VvAAT_, while 5A significantly down-regulated _VvADH2_ and SO4 significantly up-regulated _VvLOXA_ (Figure 7A). According to previous reports, we know that the unsaturated fatty acids linoleic and linoleic acids are produced by LOX and could be classified into 9-LOX and 13-LOX. Therefore, we could infer that 1103P first up-regulates _VvLOXA_, that 9-hydroperoxides and 13-hydroperoxides can be generated in the presence of _VvLOXA_, and that _VvHPL1_ catalyzes the production of hexanal by 13-hydroperoxides, which is converted to C6 alcohol by _VvADH1_ and _VvADH2_, leading to a significant increase in 1-hexanol in berries and wine. C6 esters were produced by the action of _VvAAT_, but the concentration of C6 esters in ripe grape berries was relatively low. In 2020, 1103P significantly up-regulated _VvADH2_ while significantly down-regulating _VvAAT_, 5A significantly up-regulated _VvHPL1_ and _VvADH1_ and SO4 significantly up-regulated _VvloOXC_ and _VvADH1_. _VvLOXA_, _VvHPL1_, _VvADH1_, and _VvAAT_ did not show a consistent pattern compared with 2019, which suggested that vintage was also an important factor affecting gene expression and that there may be an interactive effect between vintage and rootstock. Therefore, we performed a two-way ANOVA on vintage and rootstock and found that vintage had a highly significant effect on _VvLOXA_, _VvHPL1_, _VvADH1_, _VvADH2_, and _VvAAT_. And rootstock had a highly significant effect on _VvHPL1_, _VvADH1_, _VvADH2_, and _VvAAT_, while vintage and rootstock co-regulated _VvLOXA_, _VvLOXC_, _VvHPL1_, _VvADH1_, _VvADH2_, and _VvAAT_ (Figure 7C). Figure 6: Radar map of wine flavor profiles for different rootstock combinations in 2019 (**A**). Radar map of wine flavor profiles for different rootstock combinations in 2020 (**B**). Combined with the GLV concentrations in the grape, it was found that 1103P increased the concentrations of GLVs in grape and wine in both vintages (2019 and 2020), but we considered the main reasons for this to be different. The impact of rootstock on scion aroma substances should be considered from two perspectives: On the one hand, rootstock influenced the accumulation of GLVs by regulating the expression of genes on the LOX-HPL pathway, which was the dominant factor in the sunny and dry vintage (2019). Rootstocks were subjected to less environmental stress in this environment, resulting in less interference with genes that regulate the formation of grape aroma quality. On the other hand, excessive vegetative growth limited reproductive growth and delayed the berry ripening process, resulting in the accumulation of more GLVs in the berries, which was the main factor in the rainy and cloudy vintage (2020). In this environment, the rootstock responded more to environmental stress than it did to regulate the formation of berry aroma quality, which interfered with gene expression and led to some gene expressions that were inconsistent with those from 2019. As shown in Table S2, the pruning weight of the CS/1103P combination in 2020 was higher than both the pruning weight of the other treatments in the same year and the CS/1103P combination in 2019. In combination with the differential compounds in wine, 1-hexanol was the key compound to distinguish CS/1103P and OAVs > 1, so we concluded that the green flavor in the wine was contributed by 1-hexanol.