terclim by ICS banner
IVES 9 IVES Conference Series 9 Physiological means to curb the enthusiasm of viruses from infecting grapevines  

Physiological means to curb the enthusiasm of viruses from infecting grapevines  

Abstract

The two most deadly viruses infecting and threatening the productivity of grapevines worldwide are leafroll and red blotch viruses. There is no cure for viral diseases other than roguing the symptomatic vines and replacing them with certified vines derived from clean, virus-tested stocks. 
Given that phloem plays a central role in virus infection, this study aimed to purge the virus by girdling the phloem of leafroll-infected vines at different phenological stages of infected grapevines. Phloem-girdling was performed on canes at veraison to varying regions between the proximal and distal clusters. The vines responded to gridling by forming a callus to bridge the gap and restore vascular functionality. The whole lamina of the leaves above the girdled region turned red due to anthocyanin accumulation triggered by sugars confined to the leaf. This reddening was quite different from the reddening that typically occurs in the leafroll-infected vines, wherein the whole lamina turned red except for the lamina close to the major and minor veins, giving the impression of green veins. The girdled canes showed a low virus concentration compared to the ungirdled canes. Also, the primary metabolites, such as sugars, acids, and nitrogenous compounds, and the secondary metabolites, such as flavanols (tannins), flavonols, and anthocyanins desired for making wine did not vary much between the girdled and ungirdled shoots. This study showed that by girdling the phloem over several growing seasons can reduce the virus load in the infected vines, restoring the vine’s health.

DOI:

Publication date: June 13, 2024

Issue: Open GPB 2024

Type: Poster

Authors

Bhaskar Bondada*

Washington State University Tri-Cities, Wine Science Center, Richland, WA, USA

Contact the author*

Keywords

Acids, Anthocyanins, callus, girdling, phenolics, phloem, sugars

Tags

IVES Conference Series | Open GPB | Open GPB 2024

Citation

Related articles…

Managing soil health in vineyards: knowns and unknowns 

The use of soil conservation practices in wine grape production is becoming common throughout the world in response to an increased awareness of the value of soil health to maintain crop productivity and environmental quality. However, little information is available on the meaning of soil health within a viticultural context, and what soil properties should be targeted to achieve both the agronomic and environmental goals of wine grape producers. Conservation practices lead to increases in soil organic matter which may improve soil water retention, and increase soil C content therefore constituting a potential avenue to adapt to droughts and sequester C. Well-known management practices such as the use of cover crops, compost or no-till, although effective, seem to result in highly variable outcomes in soil organic matter and other soil health indicators. This variability is likely associated to the application of the practices in different soils and climates. Thus, integration of soil health building practices needs a thorough understanding of their efficacy under different conditions. Furthermore, additions of soil organic matter could trigger emissions of CO2 and N2O, a potent greenhouse gas that could represent a potential tradeoff of soil conservation practices. Finally, nutrient and water availability may be affected by the increase in soil organic matter having consequences for vine balance and grape quality.

Soil or geology? And what’s the difference? Some observations from the New World

Observational historical geology seeks to establish the evolutionary history of the surface of Earth. This approach is applicable not only to bedrock, but to the soft material that lies at the surface, the stuff called soil by most people. The geologic perspective provides a view of this material that is quite different from that of soil science, at least as practiced by many in America.

Grapevine nitrogen status: correlation between chlorophyll indices n-tester and spadGrapevine nitrogen status

Knowledge of the nitrogen nutrition status of grapevines is essential for the sustainable management of their nutrition for the production of quality grapes. The measurement of the chlorophyll index is a rapid, non-destructive and relatively inexpensive method that provides a good approximation of the nitrogen nutrition status of the vine during the season. Interpretation thresholds are currently insufficient or non-existent for some chlorophyll meters. Ideally, they should be available for each variety and each phenological stage. In order to popularize the use of chlorophyll-meters, measurements were carried out at Agroscope in Switzerland to establish the correlation between the indices obtained by the devices N-tester and SPAD 502.

Effect of post-harvest ozone treatment on secondary metabolites biosynthesis and accumulation in grapes and wine

The actual demand by consumers for safer and healthier food and beverage is pushing the wine sector to find alternative methods to avoid the use of sulphur dioxide in winemaking. Ozone is already used in the wine industry to produce sulphur dioxide-free wines through the patented method Purovino®.

Impact of heating must before fermentation on Chardonnay wines

Prefermentation steps of white winemaking are very important for controlling the stability and the sensory attributes of wines. Usually musts are clarified by cold settling to prevent the start of the fermentation, before racking big lees and thus limiting the appearance of vegetable or reduction off flavour while favouring an aromatic expression with low turbidity. Besides, to reach the protein stability, some white wines further require a bentonite fining, sometimes associated with negative effects on the sensory quality. This study aims to know the impact of musts heating after pressing on a Chardonnay wine in northern conditions by comparison with a classic cold racking of the must.