Variation of Growth-to-Ripening Time Interval Induced by Abscisic Acid and Synthetic Auxin affecting Transcriptome and Flavor Compounds in Cabernet Sauvignon Grape Berry

Abstract

Abscisic acid (ABA) and auxin are important hormones controlling the ripening progression of grape berry, and both the initiation and duration of ripening can dramatically affect the berry quality. However, the responses of flavor compounds to the hormones are inadequately understood. In this study, ABA and synthetic auxin α-naphthaleneacetic acid (NAA) were sprayed on Cabernet Sauvignon berries before véraison, and comparative transcriptomic and metabolic analysis were conducted to investigate the influence on berry quality-related metabolites. The 1000 mg/L ABA (ABA1000) and 200 mg/L NAA (NAA200) treated grapes exhibited shorter and longer phenological intervals compared to the control, respectively. The transcriptomic comparison between pre-véraison and véraison revealed that the varied ripening initiation and duration significantly affected the expression of genes related to specific metabolism, particularly in the biosynthetic metabolism of anthocyanin and volatile compounds. The up-regulated VviF3’H in both ABA1000-treated and NAA200-treated berries increased the proportion of 3′-substituted anthocyanins, and the 3′5′-substituted anthocyanins were largely reduced in the NAA200-treated berries. Concurrently, VviCCD4a and VviCCD4b were up-regulated, and the norisoprenoids were correspondingly elevated in the NAA200-treated berries. These data suggest that ABA and NAA applications may be useful in controlling the ripening and improving the flavor of the grape berry.

Timing of auxin treatment affects grape berry growth, ripening timing and the synchronicity of sugar accumulation

“…Gamma-butyrolactone and β-farnesene were lower in NAA wines in the current study and in Cabernet Sauvignon NAA wines from a different trial (Böttcher et al 2022), but β-farnesene was higher in wine made from NAA-treated Riesling fruit (Böttcher et al 2012). The norisoprenoid β-damascenone was higher in NAA wines in the current study (Table 1) and in Riesling NAA wines (Böttcher et al 2012) and was also shown to be higher in the juice of NAA-treated Cabernet Sauvignon berries, along with higher free and total norisoprenoids (He et al 2020). The increase observed was correlated with NAA-induced transcriptional changes to genes involved in carotenoid metabolism, such as CCD4a and 4b (He et al 2020(He et al , 2021.…”

“…The causes of the maintenance of berry mass in the later stages of ripening of NAA‐treated fruit could be manifold. Considerable changes to the expression of many genes involved in a wide range of processes occur in auxin‐treated grapes (Ziliotto et al 2012, Dal Santo et al 2020, He et al 2020, 2021). Changes to the waxy cuticle that would reduce berry transpiration is one possible mechanism by which NAA treatment might prevent berry mass loss, as cuticular conductance along with vapour pressure deficit are key determinants of transpiration mass loss (Rogiers and Holzapfel 2015, Zhang and Keller 2015).…”

“…There may be various causes for the modest changes in wine volatiles due to NAA treatment. Auxin treatment has been shown to cause quite diverse changes in the berry transcriptome (Ziliotto et al 2012, Dal Santo et al 2020, He et al 2020, 2021) and these changes might be responsible for altering berry metabolism, for example in the production of wine volatile compounds or their precursors, that are reflected in the resultant wine, or molecules that affect yeast metabolism. It is possible that synchronisation of the TSS earlier in berry ripening of NAA‐treated fruit may have subtly altered berry composition and may have played a part in the distinct volatile compound profiles seen for N1, 2, 3.…”

Combined Metabolite and Transcriptome Profiling Reveals the Norisoprenoid Responses in Grape Berries to Abscisic Acid and Synthetic Auxin

“…Alternatively, since vitispirane A, vitispirane B, and MHO exhibited lower levels in ABA-treated berries in consecutive two seasons ( Table S2 ), ABA treatments or the increased endogenous ABA may negatively regulate the accumulation of these compounds by down-regulating VviCCD4a ( Figure 2 B). The pre-veraison NAA treatment was found to increase total norisoprenoids at E-L 35 and E-L 36 stages in grape berries [ 21 ] and β-damascenone level in wine [ 3 ]. Different from ABA treatment, NAA effect on norisoprenoid biosynthesis, by comparison to ABA biosynthesis, appeared to be more apparent.…”

“…One report mentioned that the exogenous application of auxin-like compounds can delay ripening and simultaneously affect the concentration of norisoprenoids in wines [ 3 ]. Moreover, our previous study preliminarily investigated the effects of ABA and synthetic auxin 1-naphthaleneacetic acid (NAA) on anthocyanins and volatile compounds in grape berry at the beginning of ripening [ 21 ]. In the present study, we further evaluated the roles of ABA and NAA in regulating the biosynthesis of norisoprenoid at both the metabolite and transcriptional levels.…”