Temperature, water, solar radiation, and atmospheric CO
concentration are the main abiotic factors that are changing in the course of global warming. These abiotic factors govern the synthesis and ...degradation of primary (sugars, amino acids, organic acids, etc.) and secondary (phenolic and volatile flavor compounds and their precursors) metabolites directly, via the regulation of their biosynthetic pathways, or indirectly, via their effects on vine physiology and phenology. Several hundred secondary metabolites have been identified in the grape berry. Their biosynthesis and degradation have been characterized and have been shown to occur during different developmental stages of the berry. The understanding of how the different abiotic factors modulate secondary metabolism and thus berry quality is of crucial importance for breeders and growers to develop plant material and viticultural practices to maintain high-quality fruit and wine production in the context of global warming. Here, we review the main secondary metabolites of the grape berry, their biosynthesis, and how their accumulation and degradation is influenced by abiotic factors. The first part of the review provides an update on structure, biosynthesis, and degradation of phenolic compounds (flavonoids and non-flavonoids) and major aroma compounds (terpenes, thiols, methoxypyrazines, and C13 norisoprenoids). The second part gives an update on the influence of abiotic factors, such as water availability, temperature, radiation, and CO
concentration, on berry secondary metabolism. At the end of the paper, we raise some critical questions regarding intracluster berry heterogeneity and dilution effects and how the sampling strategy can impact the outcome of studies on the grapevine berry response to abiotic factors.
•The transcriptional activation activity and nuclear localization of VvWRKY30 were confirmed.•VvWRKY30 showed key transcriptional activity domain at the N-terminal and specifically binds to the ...W-BOX.•The expression of VvWRKY30 was induced by salt as well as stress signaling molecules H2S and H2O2.•Overexpression of VvWRKY30 increased plant salt stress resistance by regulating reactive oxygen species-scavenging and osmoticum accumulation.
High salinity severely inhibits the growth and productivity of grape plants. However, knowledge of salt-stress regulation remains limited in WRKY members of grapes. Here, we isolated a novel VvWRKY30 gene from Vitis vinifera L. and studied its role in salt-stress resistance. The VvWRKY30 protein fused with green fluorescent protein localized to the nucleus and the transcriptional activation activity of VvWRKY30 was confirmed in yeast. Moreover, VvWRKY30 showed key transcriptional activity domain at the N-terminal and specifically binds to the W-BOX. VvWRKY30 showed the highest expression in the shoot tip and functional leaves of grape plants. VvWRKY30 expression was induced by salt as well as stress signaling molecules H2S and H2O2. Overexpression of VvWRKY30 in Arabidopsis increased its resistance to salt stress at different stages of growth. Under salinity stress, VvWRKY30 overexpressing lines had higher antioxidant activities and lower reactive oxygen species contents. Soluble sugar and proline concentrations also increased in VvWRKY30 overexpressing lines in the presence of NaCl. In addition, the transcription of genes related to antioxidant biosynthesis, glyco-metabolism and proline biosynthesis increased in the VvWRKY30 overexpressing lines. Taken together, this study confirmed the important role of VvWRKY30 in increasing salt stress resistance by regulating reactive oxygen species-scavenging and the accumulation of osmoticum.
Premise of the Study
The stem of Vitis vinifera, a climbing vine of global economic importance, is characterized by both wide and narrow vessels and high specific hydraulic conductivity. While the ...effect of drought stress has been studied in 1‐ and 2‐yr‐old stems, there are few data documenting effects of drought stress on the anatomical structure of the mature, woody stem near the base of the vine. Here we describe mature wood anatomical responses to two irrigation regimes on wood anatomy and specific hydraulic conductivity in Vitis vinifera Merlot vines.
Methods
For 4 years, irrigation was applied constantly at low, medium, or high levels, or at alternating levels at two different periods during the growing season, either early spring or late summer, resulting in late season or early spring deficits, respectively. The following variables were measured: trunk diameter, annual ring width and area, vessel diameter, specific hydraulic conductivity and stem water potential.
Key Results
High water availability early in the season (late deficit) resulted in vigorous vegetative growth (greater trunk diameter, ring width and area), wider vessels and increased specific hydraulic conductivity. High water availability early in the season caused a shift of the vessel population towards the wider frequency classes. These late deficit vines showed more negative water potential values late in the season than vines that received low but relatively constant irrigation.
Conclusions
We concluded that high water availability during vegetative growth period of Vitis increases vessels diameter and hydraulic conductivity and causes the vines to be more vulnerable to drought stress late in the season.
Summary
Changes in the performance of genotypes in different environments are defined as genotype × environment (G×E) interactions. In grapevine (Vitis vinifera), complex interactions between ...different genotypes and climate, soil and farming practices yield unique berry qualities. However, the molecular basis of this phenomenon remains unclear. To dissect the basis of grapevine G×E interactions we characterized berry transcriptome plasticity, the genome methylation landscape and within‐genotype allelic diversity in two genotypes cultivated in three different environments over two vintages. We identified, through a novel data‐mining pipeline, genes with expression profiles that were: unaffected by genotype or environment, genotype‐dependent but unaffected by the environment, environmentally‐dependent regardless of genotype, and G×E‐related. The G×E‐related genes showed different degrees of within‐cultivar allelic diversity in the two genotypes and were enriched for stress responses, signal transduction and secondary metabolism categories. Our study unraveled the mutual relationships between genotypic and environmental variables during G×E interaction in a woody perennial species, providing a reference model to explore how cultivated fruit crops respond to diverse environments. Also, the pivotal role of vineyard location in determining the performance of different varieties, by enhancing berry quality traits, was unraveled.
Significance Statement
A dissection of grapevine G×E interaction unravels the mutual relationships between genotypic and environmental variables and defines the molecular basis of G×E‐determined qualitative berry traits.
Choosing the most appropriate rootstock(s) is a key decision for the profitability of vineyards; therefore, there must be a sufficient range of rootstocks in the market adapted to different ...environmental conditions and production objectives. However, rootstock-breeding programs have been scarce in recent decades, and most of the rootstocks used today were bred a century ago, when the needs of the sector were very different from today. In this work, we aimed to evaluate new rootstock candidates before their introduction in the market. An agronomic evaluation was conducted on eight novel rootstock genotypes obtained from the first generation of the cross-pollination of 41 B Millardet et de Grasset (41 B) and 110 Richter (110 R) grafted with ‘Syrah’ and ‘Tempranillo’ and planted in a typical vineyard of the Ebro Valley in Spain. During the four consecutive growing seasons (2016–2019), growth, yield and berry composition parameters at harvest were collected. A linear mixed-effects model was constructed, considering year and block as random effects. Multiple factor analysis and hierarchical clustering on principal components were performed to establish clusters of genotypes with similar behaviour. The rootstock candidates showed a very wide performance range compared to their parents. The trial allowed us to identify two very promising candidates (RG8 and RG10), whose registration as commercial rootstocks is already in progress.
K
is the most abundant cation in the grape berry. Here we focus on the most recent information in the long distance transport and partitioning of K
within the grapevine and postulate on the potential ...role of K
in berry sugar accumulation, berry water relations, cellular growth, disease resistance, abiotic stress tolerance and mitigating senescence. By integrating information from several different plant systems we have been able to generate new hypotheses on the integral functions of this predominant cation and to improve our understanding of how these functions contribute to grape berry growth and ripening. Valuable contributions to the study of K
in membrane stabilization, turgor maintenance and phloem transport have allowed us to propose a mechanistic model for the role of this cation in grape berry development.
•The postharvest quality of berry was maintained by exogenous melatonin.•The accumulation of amino acids was greatly promoted in response to melatonin.•The endogenous melatonin biosynthesis was ...enhanced by exogenous melatonin.•The phenolics-oriented metabolism was accelerated by dose of melatonin.
Melatonin (MLT) has gained increasing attention due to its pleiotropic effects. In present study, ‘Kyoho’ grapes were immersed in 200 μM of MLT to investigate the role of exogenous melatonin in postharvest metabolism response. Results indicated that berry abscission and rotten index was reduced by 37.50% and 58.37%, respectively, by exogenous MLT treatment, while the amino acid accumulation was greatly enhanced. Furthermore, the endogenous MLT biosynthesis was activated, where the transcript expression of genes, encoding tryptophan decarboxylase, tryptophan decarboxylase, N-acetylserotonin methyltransferase and N-acetyltransferae were upregulated significantly (p < 0.05), in accordance with the increase of endogenous MLT. Phenolic biosynthesis related genes were upregulated significantly, accompanied with the significantly higher phenolics content (p < 0.05). On day 15, the expression level of phenylalanine ammonia-lyase in MLT-treated group was twice of that in control. Therefore, this study provides the first evidence pertinent to the contribution of exogenous melatonin to the phenolics metabolism in postharvest table grape.
In the face of water stress, plants evolved with different abilities to limit the decrease in leaf water potential, notably in the daytime (ΨM). So-called isohydric species efficiently maintain high ...ΨM, whereas anisohydric species cannot prevent ΨM from dropping as soil water deficit develops. The genetic and physiological origins of these differences in (an)isohydric behaviours remain to be clarified. This is of particular interest within species such as Vitis vinifera L. where continuous variation in the level of isohydry has been observed among cultivars. With this objective, a 2 year experiment was conducted on the pseudo-F1 progeny from a cross between the two widespread cultivars Syrah and Grenache using a phenotyping platform coupled to a controlled-environment chamber. Potted plants of all the progeny were analysed for ΨM, transpiration rate, and soil-to-leaf hydraulic conductance, under both well-watered and water deficit conditions. A high genetic variability was found for all the above traits. Four quantitative trait loci (QTLs) were detected for ΨM under water deficit conditions, and 28 other QTLs were detected for the different traits in either condition. Genetic variation in ΨM maintenance under water deficit weakly correlated with drought-induced reduction in transpiration rate in the progeny, and QTLs for both traits did not completely co-localize. This indicates that genetic variation in the control of ΨM under water deficit was not due simply to variation in transpiration sensitivity to soil drying. Possible origins of the diversity in (an)isohydric behaviours in grapevine are discussed on the basis of concurrent variations in soil-to-leaf hydraulic conductance and stomatal control of transpiration.
This study on a grapevine mapping population shows that isohydric or anisohydric behaviour is under genetic control and is not simply controlled by transpiration response to soil drought.
Most modern and traditional grape-growing regions are facing challenging times due to the unpredictability of weather conditions and warming trends. Innovative and sustainable tools such as ...seaweed-based biostimulants may play a key-role in the development of environment-friendly viticultural strategies to improve yields, biotic/abiotic stress tolerance and fruit and wine quality. A sprayable Ascophyllum nodosum extract was tested on grapevines cv. Sangiovese grown under Mediterranean conditions (central Italy) and on grapevines cv. Pinot Noir and Cabernet Franc within a cool-climate viticulture region (Michigan, USA). The product was sprayed on the canopies at label doses (1.5 kg/ha) five times during the season, starting two weeks before veraison. The seaweed extract did not affect leaf gas exchanges, yield or cluster and berry size, but hastened veraison, improved anthocyanins accumulation in all cultivars and increased phenolic content particularly in Sangiovese. Therefore, medium-late application of the seaweed extract can be a simple way to favour chromatic and chemical proprieties of grapes and wines. This is the first report of positive effects of Ascophyllum nodosum extracts on the quality of cultivated wine grapes. The adoption of the technique can be particularly suitable to cool-climate viticulture, especially as it pertains to short growing seasons and genotypes with a limited phenolic profile.
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