## 2 Results and Discussion
### Subcellular Localization of VvRiLinNer Protein
Linalool showed an obvious decreasing trend during the development of both CS and Gw berries and existed predominantly in free form. At each development stage, the total concentration of free and glycosylated-bound 3\(S\)-linalool in Gw berries was always much higher than that in CS berries, a neutral grape cultivar, which was in good agreement with previous observations [2,30,31]. 3\(S\)-Linalool in young Riesling berries (4 Weeks after flowering \"WAF\" to 10 \"WAF\") was mostly present in free form and declined in the concentration, which was similar to that in Gw and CS varieties. However, a sharp increase in the level of 3\(S\)-linalool appeared from 12 WAF to 14 WAF. This accumulation pattern was also observed in several muscat vaireties, such as Muscat Hamburg, Moscato Bianco and Muscat de Frontignan [2,31,32,33,34]. This high level was kept till technological harvest (16 WAF). Furthermore, the mature Riesling berries had almost equal contents of free and glycosylated-bound 3\(S\)-linalool, which was significantly different from Gw and CS berries. Figure 5: Profiling of linalool and its related oxide in developing grape berries. Each data point is the mean of three values and their standard deviation. Different letters (a–f) indicate that the concentrations of the compound had significantly difference at \(p<0.05\) according to [PERSON]’s multiple range test in SPSS. Furan linalool oxide equivalents (FLOE). Four linalool oxides were identified from Gw and Riesling berries, including _trans_ (_cis_)-furan linalool oxides and _trans_ (_cis_)-pyran linalool oxides, whereas only two furan forms were found in CS berries. These linalool oxides existed as both free form and glycosylated-bound form in the grape cultivars studied, apart from only bound-form _trans_-pyran linalool oxide detected in the Reisling berries. For most of the individual linalool oxide, free form generally accounted for higher proportion in young berries and glycosylated-bound form took up higher proportion in mature berries. The concentration of _trans_- and _cis_-furan linalool oxides in CS berries was much lower than those in other two cultivars. In CS and Gw cultivars, total concentration of individual linalool oxide (free form plus glycosylated-bound form, \"furan linalool oxide equivalents\") in young berries were generally higher than those in mature berries. The concentration of the four glycosylated-bound linalool oxides (FLOE) all showed a significant increase from eight WAF to 10 WAF and then slightly fluctuated till mature in Gw berries, which is similar to [PERSON] _et al_. 's previous study [29]. Meanwhile the free-type linalool oxides and 3-\(S\)-linalool kept decreasing. Regarding to \"Riesling\" cultivar, the concentrations of various linalool oxides in the four WAF berries were all higher than those in the six WAF berries, and at eight WAF these compounds increased with different magnitudes and total concentration of these linalool oxides (FLOE) showed a high level in mature berries. Generally, the overall levels of monoterenes increase during grape maturation in muscat grape varieties [31,32]. In Muscat Hamburg berries, the main free monoterenes including linalool increased from veraison [2], while in Muscat de Frontignan free linalool accumulated two weeks after veraison, reached the peak level two weeks later and then decreased until harvest [33]. However the present study showed a different result, that is, total concentration of linalool and its derivatives (FLOE) presented an overall decline trend along the mature of Gw berries. The transcript abundance of the _VvRiLinNer_ was assessed throughout the whole berry development stages. The expression trends of this gene were quite similar in the three grape cultivars (Figure 6). A sharp decrease in expression level was observed from four WAF to eight WAF, which highly positively correlated to the change of total concentration of linalool and its structure-linked compounds.