Grapevine Plasticity in Response to an Altered Microclimate: Sauvignon Blanc Modulates Specific Metabolites in Response to Increased Berry Exposure

Abstract

M.A.V.).In this study, the metabolic and physiological impacts of an altered microclimate on quality-associated primary and secondary metabolites in grape (Vitis vinifera) 'Sauvignon Blanc' berries was determined in a high-altitude vineyard. The leaf and lateral shoot removal in the bunch zones altered the microclimate by increasing the exposure of the berries. The physical parameters (berry diameter and weight), primary metabolites (sugars and organic acids), as well as bunch temperature and leaf water potential were predominantly not affected by the treatment. The increased exposure led to higher levels of specific carotenoids and volatile terpenoids in the exposed berries, with earlier berry stages reacting distinctly from the later developmental stages. Plastic/nonplastic metabolite responses could be further classified to identify metabolites that were developmentally controlled and/or responded to the treatment in a predictable fashion (assessed over two consecutive vintages). The study demonstrates that grapevine berries exhibit a degree of plasticity within their secondary metabolites and respond physiologically to the increased exposure by increasing metabolites with potential antioxidant activity. Taken together, the data provide evidence that the underlying physiological responses relate to the maintenance of stress pathways by modulating antioxidant molecules in the berries.Vineyards are highly variable environments where the plant must respond to changes within and across seasons. Grapevine (Vitis vinifera) berry ripening occurs over months, and the final berry composition is the expression of the interaction between the specific genotype (cultivar) and the environment over time (vintage). The grape and wine industries rely on cultivars and clones that have been purposefully selected and domesticated for thousands of years based on predominantly observable phenotypes (color, flavor/aroma, and/or survival [i.e. resistance to biotic/abiotic stresses]; Terral et al., 2010;Bouby et al., 2013). The genetic basis of these traits obviously underpins a biological function in the plant, but these functions and underlying mechanisms are still relatively poorly studied in grapevine.

Impact of agronomic practices on grape aroma composition: a review

“…Such timing issues should be analyzed as related to regional agro‐climatic conditions. Carotenoids, C13‐norisoprenoid and terpenol concentrations also increased in berries of Sauvignon directly exposed to solar radiation after leaf removal …”

“…Some of these compounds, such as 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN), which are detected at very low thresholds (e.g., 20 ppb in Riesling wines), provide a very distinctive flavor of kerosene scent. 95 Many authors 2,25,63,[73][74][75]95 have studied the influence of bunch exposure to sunlight on glycosylated and/or free C 13 -norisoprenoids. The effect of sunlight and shade on the C 13 -norisoprenoid levels found in Riesling and Chenin berries has been reported.…”

“…Carotenoids, C13-norisoprenoid and terpenol concentrations also increased in berries of Sauvignon directly exposed to solar radiation after leaf removal. 25 The effect of canopy shading in glycoconjugate monoterpenes and C 13 -norisoprenoids was studied in Sauvignon grapes. 76 The authors observed that the concentration of these molecules wileyonlinelibrary.com/jsfa decreased when canopy density was higher, while IBPM concentrations increased.…”

“…[12][13][14][15][16][17][18][19][20][21][22][23][24] Understanding how these factors affect grapes' composition is critical to developing strategies for adapting viticultural practices to climate change. [25][26][27] Plant volatile compounds (VOCs), which are determined by the variety and may be influenced by vineyard management and biotic or abiotic stresses, have a key role in grape quality. They are secondary metabolites, and, as shown in previous research on phenolic compounds, 28 agronomic practices can influence the content and profile of secondary metabolites in two different ways: directly, where biosynthesis of the molecules changes as a result of agronomic practice, and indirectly, as a consequence of a variation in the concentration of the molecules, due to changes in the fruit volume and weight.…”

Grape berry position affects the diurnal dynamics of its metabolic profile

“…The effect of solar irradiance and air temperature on the accumulated levels and composition of numerous primary and secondary metabolites were extensively described (Cohen, Tarara, Gambetta, Matthews, & Kennedy, ; Haselgrove et al, ; Pereira et al, ; Reshef, Agam, & Fait, ; Reshef, Walbaum, Agam, & Fait, ; Spayd, Tarara, Mee, & Ferguson, ; Young et al, ). Nevertheless, daily changes in the levels of fruit primary and secondary metabolites and their underlying causes received little attention.…”