Macrowine 2021
IVES 9 IVES Conference Series 9 Microbial life in the grapevine: what can we expect from the leaf microbiome?

Microbial life in the grapevine: what can we expect from the leaf microbiome?

Abstract

The above-ground parts of plants, which constitute the phyllosphere, have long been considered devoid of bacteria and fungi, at least in their internal tissues and microbial presence there was long considered a sign of disease. However, recent studies have shown that plants harbour complex bacterial communities, the so-called “microbiome”[1]. We are only beginning to unravel the origin of these bacterial plant inhabitants, their community structure and their roles, which in analogy to the gut microbiome, are likely to be of essential nature. Among their multifaceted metabolic possibilities, bacteria have been recently demonstrated to emit a wide range of volatile organic compounds (VOCs), which can greatly impact the growth and development of both the plant and its disease-causing agents. In particular, these VOCs have been shown to promote root growth and thereby nutrient acquisition and growth, but also to induce plant resistance against diseases [2-4]. Their effects on fungal and oomycete pathogens range from mycelium growth reduction to inhibition of sporulation, zoospore release and even death, although much of these reports are based on experiments performed in controlled laboratory conditions with model plants [5]. Preliminary experiments indicate that these VOCs could also confer protection against oomycete pathogens grown in planta [6]. This presentation will summarize the present state of knowledge in both fields of research, the phyllosphere microbiome and the bacterial emission of VOCs, and highlight the potential these new fields offer for sustainable viticulture.

1. Vorholt JA. 2012. Microbial life in the phyllosphere. Nat Rev Micro 10:828-840. 2. Ryu CM, Farag MA, Hu CH, Reddy MS, Kloepper JW, Pare PW. 2004. Bacterial volatiles induce systemic resistance in Arabidopsis. Plant Physiol 134:1017-1026. 3. Ryu CM, Farag MA, Hu CH, Reddy MS, Wei HX, Pare PW, Kloepper JW. 2003. Bacterial volatiles promote growth in Arabidopsis. P Natl Acad Sci USA 100:4927-4932. 4. Bailly A, Groenhagen U, Schulz S, Geisler M, Eberl L, Weisskopf L. 2014. The inter-kingdom volatile signal indole promotes root development by interfering with auxin signalling. Plant J 80:758-771. 5. Weisskopf L. 2014. The potential of bacterial volatiles for crop protection against phytophathogenic fungi. In Méndez-Vilas A (ed.), Microbial pathogens and strategies for combating them: science, technology and education. Formatex Research Center, online resource. 6. DeVrieze M, Pandey P, Bucheli TD, Varadarajan AR, Ahrens CH, Weisskopf L, Bailly A. 2015. Volatile organic compounds from native potato-associated Pseudomonas as potential anti-oomycete agents. Front Microbiol 6.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Article

Authors

Laure Weisskopf*

*HES-SO

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Evaluating South African Chenin blanc wine styles using an LC-MS screening method

Sorting Chenin blanc is one of the most important white wine cultivars in South Africa. It has received a lot of attention and accolades in the past years and more research than ever is dedicated to this versatile cultivar. According to the Chenin blanc association of South Africa, there are three recognized dry wine styles, Fresh and Fruity (FF), Rich and Ripe Unwooded
(RRU), and Rich and Ripe Wooded (RRW). They are traditionally established with the aid of expert sensory evaluation, but the cost and the (subjective) human factor are aspects to be taken into account. A more objective and possibly robust way of assessing and attributing these styles can be the use of chemical analysis.

Study of the volatil profile of minority white varieties

The genetic material preservation is a priority issue in winemaking research. The recovery of minority grape varieties can control the genetic erosion, contributing also to preserve wine typical characteristics. In D.O.Ca. Rioja (Spain) the number of grown white varieties has been very limited, representing Viura the 91% of the cultivated white grape area in 2005, while the others, Garnacha Blanca and Malvasía riojana, hardly were grown. For this reason, a recovery and characterization study of plant material was carried out in this region. In 2008, the results obtained allowed the authorization of three minority white varieties: Tempranillo Blanco, Maturana Blanca and Turruntés.

Crown procyanidin: a new procyanidin sub-family with unusual cyclic skeleton in wine

Condensed tannins (also called proanthocyanidins) are a widely distributed throughout in plants kingdom and are one of the most important classes of secondary metabolites, in addition, they are part of the human diet. In wine, they are extracted during the winemaking process from grape skins and seeds. These compounds play an important role in red wine organoleptic characteristics such as color, bitterness and astringency. Condensed tannins in red wine are oligomers and polymers of flavan-3-ols unit such as catechin, epicatechin, epigallocatechin and epicatechin-3-O-gallate. The monomeric units can be linked among them with direct interflavanoid linkage or mediated by aldehydes.

Using elicitors in different grape varieties. Effect over their phenolic composition

Phenolic compounds are very important in crop plants and have been the subject of a large number of studies. Three main reasons can be cited for optimizing the level of phenolic compounds in crop plants: their physiological role in plants, their technological significance for food processing, and their nutritional characteristics1 Indeed, an enormous diversity of phenolic antioxidants is found in fruits and vegetables, and their presence and roles can be affected or modified by several pre- and postharvest cultural practices and/or food processing technologies (Ruiz-García et al. 2012, Goldman et al. 1999, Tudela et al. 2002). In winegrapes, the technological importance of phenolic compounds, mainly flavonoids, is well-known.

How do different oak treatment affect the sensory composition of Chenin blanc wines over time?

Wooden barrels have been the preferred method for oak maturation for wines, but the use of alternative oak products, such as staves and oak chips have increased in South Africa due to lower production costs. This study investigated the effect of different oak products used during fermentation and ageing on the sensory profile, degree of liking and perceived quality of a South African Chenin blanc wine. The different wine treatments included an unoaked tank control wine, wines matured in 5th fill barrels, wines matured in new barrels from three different cooperages, and wines matured in 5th fill barrels with stave inserts from two different cooperages.