The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is an invasive polyphagous pest often observed in vineyards. In Europe, a gap needs to be filled in the knowledge ...on H. halys seasonal dynamics and damage on grapes. With this study, we described the seasonal dynamics of H. halys and its distribution in multi-cultivar vineyards, and we evaluated the damage on grape clusters induced by different pest densities. In vineyards, the seasonal occurrence of H. halys varied across time and grape cultivars, and the pest was more abundant on Cabernet Franc, Merlot and, to a lesser extent, Pinot gris. Moreover, higher densities of H. halys were found on red berry cultivars than on white ones, and on cultivars ripening late in the season. An edge effect was also detected in pest distribution within vineyards, with more stink bugs observed in the borders. In the study on pest infestation density, H. halys caused damage on berries, showing differences in susceptibility among different cultivars and with regard to the time of infestation (i.e., plant phenological stages). Halyomorpha halys infestation induced an increase in Botrytis cinerea and sour rot incidence, which probably represents the main issue related to the impact of brown marmorated stink bug on grapevine.
Grapevine trunk diseases (GTDs) are a substantial challenge to viticulture, especially with a lack of available control measures. The lack of approved fungicides necessitates the exploration of ...alternative controls. One promising approach is the investigation of disease escape plants, which remain healthy under high disease pressure, likely due to their microbiome function. This study explored the microbiome of grapevines with the disease escape phenotype. DNA metabarcoding of the ribosomal internal transcribed spacer 1 (ITS1) and 16S ribosomal RNA gene was applied to trunk tissues of GTD escape and adjacent diseased vines. Our findings showed that the GTD escape vines had a significantly different microbiome compared with diseased vines. The GTD escape vines consistently harbored a higher relative abundance of the bacterial taxa
Pseudomonas
and
Hymenobacter
. Among fungi,
Aureobasidium
and
Rhodotorula
were differentially associated with GTD escape vines, while the GTD pathogen,
Eutypa
, was associated with the diseased vines. This is the first report of the link between the GTD escape phenotype and the grapevine microbiome.
•The sensitivity of two primer sets of GRSPaV was different, and RSP52/53 was better than RSP9F/9R.•The detection efficiency of GRSPaV in different parts of grapevines was different.•The titers of ...GRSPaV in upper above-ground and root parts of in vitro grapevine were higher.•Phloem of shoots and in vitro plants were suitable to GRSPaV detection.
Grapevine rupestris stem pitting-associated virus (GRSPaV) is a widespread virus of grapevine. In this study, we compared the detection efficiencies of two primer sets and evaluated virus distribution among different grapevine materials. The results of RT-PCR analyses showed that primer pair RSP52/53 was 10% more sensitive than RSP9F9R, with total detection rates of 89.3% and 78.6%, respectively. Five different parts of six grapevine cultivars, which were collected in May and August, were used as materials in GRSPaV detection analyses. The results showed that the fourth petioles were a suitable material for analysis, and fourth petiole materials collected in May and August yielded the same result (50.0%). The plant parts could be ranked, from highest virus detection efficiency to lowest, as follows: phloem > berries ≈ fourth petioles > tendrils > new leaves ≈ fourth leaves. A comparison of the titers of GRSPaV among the upper, middle, and lower above-ground parts and roots of three in vitro grapevine samples by quantitative real-time PCR showed that the highest concentration of GRSPaV was in the root, followed by the upper above-ground part.
Grapevine downy mildew is the most serious disease of grapevine cultivars that affects the rate of resistance/susceptibility to
. In this study, we used the susceptible cultivar "Zitian Seedless" and ...the resistant cultivar "Kober 5BB" as materials to determine the transcriptome differences and phenotypes of the leaves after inoculation with downy mildew. The differences in microstructures and molecular levels were compared and analyzed. Fluorescence staining and microscopic observations confirmed that hypersensitive cell death occurred around the stomata in "Kober 5BB" infected by downy mildew zoospores. Meanwhile, transcriptomic profiling indicated that there were 11,713 and 6,997 gene expression differences between the resistant and susceptible cultivars at 72 h after inoculation when compared to control (0 h), respectively. The differentially expressed genes of the two cultivars are significantly enriched in different pathways, including response to plant-pathogen interaction, mitogen-activated protein kinase (MAPK) signaling pathway, plant hormone signal transduction, phenylpropanoid, and flavonoid biosynthesis. Furthermore, the results of functional enrichment analysis showed that H
O
metabolism, cell death, reactive oxygen response, and carbohydrate metabolism are also involved in the defense response of "Kober 5BB," wherein a total of 322 key genes have been identified. The protein interaction network showed that metacaspases (MCAs), vacuolar processing enzymes (VPEs), and Papain-like cysteine proteases (PLCPs) play an important role in the execution of hypersensitive responses (HR). In conclusion, we demonstrated that HR cell death is the key strategy in the process of grape defense against downy mildew, which may be mediated or activated by Caspase-like proteases.
Warm and moist weather conditions during berry ripening provoke Botrytis cinerea (B. cinerea) causing notable bunch rot on susceptible grapevines with the effect of reduced yield and wine quality. ...Resistance donors of genetic loci to increase B. cinerea resistance are widely unknown. Promising traits of resistance are represented by physical features like the thickness and permeability of the grape berry cuticle. Sensor-based phenotyping methods or genetic markers are rare for such traits. In the present study, the simple-to-handle I-sensor was developed. The sensor enables the fast and reliable measurement of electrical impedance of the grape berry cuticles and its epicuticular waxes (CW). Statistical experiments revealed highly significant correlations between relative impedance of CW and the resistance of grapevines to B. cinerea. Thus, the relative impedance Zrel of CW was identified as the most important phenotypic factor with regard to the prediction of grapevine resistance to B. cinerea. An ordinal logistic regression analysis revealed a R2McFadden of 0.37 and confirmed the application of Zrel of CW for the prediction of bunch infection and in this way as novel phenotyping trait. Applying the I-sensor, a preliminary QTL region was identified indicating that the novel phenotypic trait is as well a valuable tool for genetic analyses.
•Early budburst is becoming a general issue in viticulture, yet quantitative methods of assessment are lacking.•Ecodormancy release in grapevine can be monitored dynamically via chlorophyll ...fluorescence emission from the bud section.•Genotypic variation for thermal requests to reach budburst has been detected and validated via several methods.•Genotypic variation for dynamic late frost tolerance is present in Vitis vinifera.
Early budburst is becoming an increasingly challenging topic in viticulture. Anticipating vegetative resume results in an overall phenological advance, in potential higher risks of late frost and subsequent negative effects on berry quality and overall vine productivity. Phenotypic variation for date of budburst onset (BBCH07) is known in Vitis vinifera and potential exploitation of data regarding thermal requests to reach BBCH07 are critical in defining new avenues for viticulture. Nevertheless, reproducible methods are lacking in defining phenological progression in grapevine and further efforts are needed to standardize quantitative dataset associated with early growth stages appearance. In this work, a panel of twenty-one Vitis vinifera varieties grown in an experimental vineyard were assessed for early phenological onset (pre-to-post budburst) via visual observation, quantum yield of photosystem II in the dark adapted (Fv/Fm) bud section and growing degree days accumulation over three years. Further experiments were carried out under controlled environmental conditions to evaluate the effect of different simulated late frost on bud viability. Our data proposes Fv/Fm from bud section as a quantitative and reliable tool, although destructive following our pipeline, to monitor early phenological events in grapevine with significant non-linear associations of the Fv/Fm with growing degree days on base 6 °C (GDD6) and phenology. We observed significant (p < 0.001) inter-varietal variation for thermal requests to reach budburst ranking from 140 to 260 GDD6 although some varieties showed inconsistent data between years (i.e. a plastic response). Late frost damage was associated with phenological progression suggesting a linear and positive correlation between cold injury and de-acclimation from cold hardiness up until first leaf appearance. However, monitoring Fv/Fm in selected varieties provided evidence of varietal-specific response to late frost with e.g., Chardonnay and Gewürztraminer showing maintenance of photosystem II activity even at advanced phenological stages. This suggests the presence of preferable acclimation mechanisms to late frost in Vitis vinifera that will deserve further investigation. Our data provides a comprehensive analysis of early phenological events in grapevine, providing novel methods of assessment (Fv/Fm), varieties possessing escape strategies (i.e. large thermal accumulation to reach BBCH07) and varieties with putative late frost tolerance even after budburst. Overall, further work is ongoing to define the mechanisms underlying late frost tolerance per se and to identify novel varieties with preferable combination of traits.
•Tempranillo was more affected by water stress than Benedicto and Moribel.•Mainly Benedicto could be considered a more suitable variety than Tempranillo.•Benedicto wines were the ones that exhibited ...the highest quality.
The effects of climate change are an emerging threat that is compromising the sustainability of grapevine growing worldwide. The Tempranillo variety is no stranger to this threat. In fact, in recent decades, significant losses have occurred in the yield and quality of Tempranillo grapes for winemaking. This problem is particularly serious in Spain, where Tempranillo is the red variety par excellence for the production of great wines. In this study, we assessed whether two genetically related varieties could exhibit a better drought response than Tempranillo itself. During two consecutive seasons, a study was conducted including the Tempranillo, Benedicto, and Moribel varieties, which were grown under two different water deficit regimes. The phenology of the varieties was followed, and components of yield, vigor, quality parameters, and δ13C were analyzed. The results revealed that Tempranillo was the variety most affected by water stress, exhibiting significantly higher δ13C than its relatives. Without compromising yield, Benedicto and Moribel responded better than Tempranillo to drought conditions, exhibiting better must quality even in the warmer season. The wines coming from Benedicto exhibited the highest quality because of their high total acidity, anthocyanin concentration, color intensity, and low pH. Although all three wines exhibited a similar profile, in the sensory analysis, tasters mostly preferred Benedicto and Moribel wines to Tempranillo ones.
Fruit composition at harvest is strongly dependent on the temperature during the grapevine developmental cycle. This raises serious concerns regarding the sustainability of viticulture and the ...socio-economic repercussions of global warming for many regions where the most heat-tolerant varieties are already cultivated. Despite recent progress, the direct and indirect effects of temperature on fruit development are far from being understood. Experimental limitations such as fluctuating environmental conditions, intra-cluster heterogeneity and the annual reproductive cycle introduce unquantifiable biases for gene expression and physiological studies with grapevine. In the present study, DRCF grapevine mutants (microvine) were grown under several temperature regimes in duly-controlled environmental conditions. A singly berry selection increased the accuracy of fruit phenotyping and subsequent gene expression analyses. The physiological and transcriptomic responses of five key stages sampled simultaneously at day and nighttime were studied by RNA-seq analysis.
A total of 674 millions reads were sequenced from all experiments. Analysis of differential expression yielded in a total of 10 788 transcripts modulated by temperature. An acceleration of green berry development under higher temperature was correlated with the induction of several candidate genes linked to cell expansion. High temperatures impaired tannin synthesis and degree of galloylation at the transcriptomic levels. The timing of malate breakdown was delayed to mid-ripening in transgressively cool conditions, revealing unsuspected plasticity of berry primary metabolism. Specific ATPases and malate transporters displayed development and temperature-dependent expression patterns, besides less marked but significant regulation of other genes in the malate pathway.
The present study represents, to our knowledge the first abiotic stress study performed on a fleshy fruits model using RNA-seq for transcriptomic analysis. It confirms that a careful stage selection and a rigorous control of environmental conditions are needed to address the long-term plasticity of berry development with respect to temperature. Original results revealed temperature-dependent regulation of key metabolic processes in the elaboration of berry composition. Malate breakdown no longer appears as an integral part of the veraison program, but as possibly triggered by an imbalance in cytoplasmic sugar, when efficient vacuolar storage is set on with ripening, in usual temperature conditions. Furthermore, variations in heat shock responsive genes that will be very valuable for further research on temperature adaptation of plants have been evidenced.
ABSTRACTTemperate regions experiencing sub-zero temperatures negatively impact grapevine yield. Potassium has been claimed as a cryoprotectant to improve cold hardiness in grapevine. This study ...investigated the effect of foliar application of liquid potassium-based fertilizer, ReaXTM, on cold-hardiness of grapevine Vitis spp. “Chambourcin” along with its effect on yield and fruit quality. The vines were sprayed four to five times between the fruit set and veraison stage at a concentration of 1.5% (v/v) for two consecutive seasons. Petioles were analyzed for nutrients, clusters for yield and fruit quality, and cold hardiness was determined by differential thermal analysis and bud injury assessment. Potassium deficiency was observed in all treatments, and its content did not increase significantly in treated vines. Berry potassium levels and total soluble solids were generally higher in K-treated vines, however, there was no significant effect on yield and other fruit quality traits. Significant differences in cold hardiness levels were observed in both dormant seasons. Foliar application of potassium is a promising cultural practice to increase cold hardiness, but further studies are needed to understand the limits of its effectiveness.
Summary
Powdery mildew (PM) is a severe fungal disease of cultivated grapevine world‐wide. Proanthocyanidins (PAs) play an important role in resistance to fungal pathogens; however, little is known ...about PA‐mediated PM resistance in grapevine.
We identified a WRKY transcription factor, VqWRKY56, from Vitis quinquangularis, the expression of which was significantly induced by PM.
Overexpression (OE) of VqWRKY56 in Vitis vinifera increased PA content and reduced susceptibility to PM. Furthermore, the transgenic plants showed more cell death and increased accumulation of salicylic acid and reactive oxygen species. Transient silencing of VqWRKY56 in V. quinquangularis and V. vinifera reduced PA accumulation and increased the susceptibility to PM. VqWRKY56 interacted with VqbZIPC22 in vitro and in planta. The protein VqWRKY56 can bind to VvCHS3, VvLAR1, and VvANR promoters, and VqbZIPC22 can bind to VvANR promoter. Co‐expression of VqWRKY56 and VqbZIPC22 significantly increased the transcript level of VvCHS3, VvLAR1, and VvANR genes. Finally, transient OE of VqbZIPC22 in V. vinifera promoted PA accumulation and improved resistance to PM, while transient silencing in V. quinquangularis had the opposite effect.
Our study provides new insights into the mechanism of PA regulation by VqWRKY56 in grapevine and provides a basis for further metabolic engineering of PA biosynthesis to improve PM resistance.
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