The Expression of Aroma Components and Related Genes in Merlot and Marselan Scion-Rootstock Grape and Wine

Abstract

Rootstocks were bred and selected from several species in order to enhance the resistance against biotic or abiotic stresses. There are few studies on the effect of rootstocks on aroma and related gene expression. This study focused on the effects of three rootstocks, Kober 5BB (5BB), 1103 Paulsen (1103P), and Selection Oppenheim (SO4), on the aroma and volatile-related gene expression levels of Merlot and Marselan berries and wines. These three rootstocks reduced the total aroma content of Merlot wine. 5BB upregulated VvLoXA and showed increased C6 alcohols. 1103P enhanced the linalool from Merlot berry, with marked upregulation of VvLinNer1. Conversely, rootstocks increased the total aroma content of Marselan berry, verified by the related expression levels of volatile-related genes. For Marselan berry, 5BB and 1103P upregulated five VvGTs and nine genes from the LOX and MEP pathway. 1103P increased the contents of C6 alcohols, C6 aldehydes, and citronellol from Marselan berry. Compared to 5BB and SO4, rootstock 1103P provided berries of better quality and richer aroma volatiles to Merlot and Marselan, while all three of the rootstocks had a significant effect on scion-rootstocks.

Keywords: C6 compounds; LOX pathway; scion–rootstock; volatile-related gene expressions.

Figure 1

Change in the expression of the volatile-relative genes of Merlot and Marselan. (A) VvDXS1, VvDXS3, VvDXR, VvHDR from the MEP pathway. (B) VvLoXA, VvADH1, VvADH2, VvADH3 from the LOX pathway. (C) VvGPPS, VvFPPS, VvLinNer1, VvLinNer2 from the MEP pathway. (D) VvCCD1, VvCCD4a, VvCCD4b from the C13-compound synthesis pathway. (E) VvGT5, VvGT6, VvGT7, VvGT9, VvGT14 for the synthesis of glycosylated volatile compounds. Data are the mean concentration (n = 3). Different letters show significant differences between treatments by Duncan’s multiple range test (p ≤ 0.05).