Showing papers by "Eric Gomès published in 2015"
TL;DR: Under drought stress, berries from vines grafted on 110R displayed a different transcriptional response compared to 125AA-concerning genes related to jasmonate (JA), phenylpropanoid metabolism, and pathogenesis-related proteins, which suggest a link between JA and secondary metabolism in water-stressed berries.
Abstract: Grapevine is a perennial crop often cultivated by grafting a scion cultivar on a suitable rootstock. Rootstocks influence scions, particularly with regard to water uptake and vigor. Therefore, one of the possibilities to adapt viticulture to the extended drought stress periods is to select rootstocks conferring increased tolerance to drought. However, the molecular mechanisms associated with the ability of rootstock/scion combination to influence grape berry metabolism under drought stress are still poorly understood. The transcriptomic changes induced by drought stress in grape berries (cv. Pinot noir) from vines grafted on either 110R (drought-tolerant) or 125AA (drought-sensitive) rootstock were compared. The experiments were conducted in the vineyard for two years and two grape berry developmental stages (50% and 100% veraison). The genome-wide microarray approach showed that water stress strongly impacts gene expression in the berries, through ontology categories that cover cell wall metabolism, primary and secondary metabolism, signaling, stress, and hormones, and that some of these effects strongly depend on the rootstock genotype. Indeed, under drought stress, berries from vines grafted on 110R displayed a different transcriptional response compared to 125AA-concerning genes related to jasmonate (JA), phenylpropanoid metabolism, and pathogenesis-related proteins. The data also suggest a link between JA and secondary metabolism in water-stressed berries. Overall, genes related to secondary metabolism and JA are more induced and/or less repressed by drought stress in the berries grafted on the drought-sensitive rootstock 125AA. These rootstock-dependent gene expression changes are relevant for berry composition and sensory properties.
90 citations
TL;DR: Under carbon limitation, the grape berry can manage the metabolic fate of carbon in such a way that sugar accumulation is maintained at the expense of secondary metabolites.
Abstract: Grape berry composition mainly consists of primary and secondary metabolites. Both are sensitive to environment and viticultural management. As a consequence, climate change can affect berry composition and modify wine quality and typicity. Leaf removal techniques can impact berry composition by modulating the source-to-sink balance and, in turn, may mitigate some undesired effects due to climate change. The present study investigated the balance between technological maturity parameters such as sugars and organic acids, and phenolic maturity parameters such as anthocyanins in response to source-sink modulation. Sugar, organic acid, and anthocyanin profiles were compared under two contrasting carbon supply levels in berries of cv. Cabernet Sauvignon and Sangiovese collected at 9 and 14 developmental stages respectively. In addition, whole-canopy net carbon exchange rate was monitored for Sangiovese vines and a mathematic model was used to calculate the balance between carbon fixation and berry sugar accumulation. Carbon limitation affected neither berry size nor the concentration of organic acids at harvest. However, it significantly reduced the accumulation of sugars and total anthocyanins in both cultivars. Most interestingly, carbon limitation decreased total anthocyanin concentration by 84.3% as compared to the non source-limited control, whereas it decreased sugar concentration only by 27.1%. This suggests that carbon limitation led to a strong imbalance between sugars and anthocyanins. Moreover, carbon limitation affected anthocyanin profiles in a cultivar dependent manner. Mathematical analysis of carbon-balance indicated that berries used a higher proportion of fixed carbon for sugar accumulation under carbon limitation (76.9%) than under carbon sufficiency (48%). Thus, under carbon limitation, the grape berry can manage the metabolic fate of carbon in such a way that sugar accumulation is maintained at the expense of secondary metabolites.
72 citations
TL;DR: The hastening effect of climate change conditions on ripening, associated to higher rates of carbon fixation, was attenuated byUV-B radiation, which suggests that UV-B may contribute to palliate the signs of oxidative damage induced under elevated CO2-temperature.
58 citations
TL;DR: The flavonol profiles of grape berry skins were analysed in order to assess phenotypic variation between six grapevines belonging to six different species and the new Flavonol diglycoside and pentoside derivatives were determined.
40 citations
TL;DR: In summary, deficit irrigation did not modify the adaptive response of grapevine to UV-B, through the accumulation of MEUVAC, however, combined treatments caused additive effects on berry ripening.
35 citations
TL;DR: This result indicates that when an effect of N on IBMP was found in previous studies, it was likely mediated through the modification of bunch-zone microclimate, induced by the higher vigor of high N-status vines.
Abstract: Methoxypyrazines (MP) constitute a large family of compounds that contribute to the vegetative varietal aroma of many grapevine varieties and wines. The berry content in 2-methoxy-3-isobutylpyrazine (IBMP), a major MP reminiscent of green-pepper aroma, can be influenced by environmental factors or cultural practices such as water status or mineral nutrition. To date, no study has investigated a possible direct effect of nitrogen (N) on IBMP synthesis without possible interference from water status and vigor variations. In this study, only vine nitrogen status was significantly different among treatments. Water status was controlled during the season, and vine vigor was similar among treatments. IBMP level was maximal at bunch closure and decreased during the season. There was no significant effect of nitrogen nutrition on this metabolite. Moreover, the expression profiles of VvOMT3 and VvOMT4, key genes in the IBMP biosynthetic pathway, were similar between treatments. This result indicates that when an e...
14 citations