Grapevine Metabolomics Reveals How Tolerant and Susceptible Cultivars Fight a Deadly Trunk Disease Fungus Differently

Grapevine trunk diseases have become one of the most pressing threats to vineyards worldwide, quietly destroying vines and undermining the economic foundations of wine production across every major growing region. Among the pathogens responsible, the fungus Neofusicoccum parvum stands out as one of the most aggressive members of the Botryosphaeriaceae family, the fungal group behind Botryosphaeria dieback, a disease that kills woody tissue and produces the characteristic foliar symptoms that growers dread. A new study published in BMC Plant Biology by Alexia Laura Grau, Nathalie Lacrampe, Mary-Lorène Goddard and Julie Chong of the Université de Haute Alsace and their collaborators now offers an unusually detailed picture of how two grapevine cultivars with contrasting field behavior respond to this pathogen at the level of their entire metabolism, from roots to leaves.

The research team set out to answer a question that has long frustrated plant pathologists and viticulturists alike: why do some grapevine cultivars tolerate infection by trunk disease fungi while others succumb, even though no grapevine genotype is fully resistant? Tolerance in this context is measured by the expression of foliar symptoms, which varies considerably among cultivars, yet the biochemical mechanisms underlying this variation have remained poorly understood. To probe the question, the researchers chose two cultivars with well-documented contrasting responses to Botryosphaeria dieback: Chardonnay, which shows greater tolerance, and Gewurztraminer, which is more susceptible. By comparing how these two cultivars reconfigure their chemistry after infection, the team hoped to identify the metabolic signatures that separate a resilient vine from a vulnerable one.

The experimental design was ambitious in scope. Rather than examining only the infection site in the woody stem, as most earlier studies have done, the researchers conducted whole-plant metabolomic analyses, sampling wood, leaves and roots at different times after inoculation. They used untargeted liquid chromatography coupled with mass spectrometry, a technique that allows scientists to detect and measure thousands of small molecules simultaneously without knowing in advance which ones will prove important. This unbiased approach is critical when studying complex plant-pathogen interactions, because defense chemistry often involves unexpected compounds and pathways that a targeted analysis would miss entirely.

A key feature of the study was the use of two different N. parvum isolates that differ in aggressiveness. Pathogen colonization assays confirmed that the two isolates possessed contrasting wood invasion capacities, with one spreading more extensively through the host tissue than the other. This distinction mattered: it allowed the researchers to separate the effects of the plant cultivar from the effects of the fungal strain, revealing that the outcome of infection depends on the specific pairing of host and pathogen rather than on a generic interaction between grapevine and wood-decay fungus. The two isolates used in the work were designated Np.Bt67 and Np.Bourgogne, and their differing behavior in the wood provided a natural experiment in fungal virulence.

When the team analyzed the resulting metabolomic data using principal component analysis, a statistical method that reveals the dominant sources of variation in large datasets, a clear pattern emerged. The cultivar of the vine and the identity of the fungal isolate were the main factors structuring metabolic variation across the experiment, with additional contributions from the organ being sampled and the time elapsed since inoculation. In other words, the chemical state of a vine after infection is not determined by the fungus alone or the plant alone, but by the interplay between a particular cultivar and a particular fungal isolate, modulated by where in the plant one looks and how long the infection has had to develop.

The most striking differences appeared in the wood, the primary battleground between vine and pathogen. In response to the most aggressive isolate, the two cultivars mounted clearly distinct metabolic responses, particularly in their profiles of stilbenes and oxylipins. Stilbenes are a family of phenolic compounds, including the famous resveratrol, that grapevines synthesize as antifungal weapons, and their production is governed by enzymes such as stilbene synthase and the upstream phenylalanine ammonia-lyase, both central players in plant defense. Oxylipins, by contrast, are oxygenated derivatives of fatty acids produced through the lipoxygenase pathway, and they serve as both antimicrobial compounds and signaling molecules that coordinate defense responses across the plant.

Here the tolerant cultivar revealed its hand. Compared with Gewurztraminer, Chardonnay showed a faster and stronger induction of stilbene and fatty acid synthesis in its wood, especially of oxylipins, compounds that could be involved in both direct defense and long-distance signaling. This rapid chemical mobilization suggests that the tolerant vine does not simply produce more of the right compounds at the end of the battle; it activates its defensive chemistry earlier and more vigorously, potentially slowing the pathogen before it can establish a firm foothold. Notably, the study found that pathogen growth was similar between the two cultivars, meaning that the difference in tolerance cannot be explained by the fungus simply growing more slowly in Chardonnay. Instead, the two cultivars are characterized by specific metabolite signatures, especially in the wood, pointing to fundamentally different interaction mechanisms rather than a common response to wood decay.

Perhaps the most surprising finding came from beyond the infection site. The researchers observed that leaves and roots also exhibited early metabolic adjustments after the fungus was introduced into the wood, and these systemic changes were more pronounced in Chardonnay than in Gewurztraminer. This indicates that the tolerant cultivar mounts a rapid whole-plant response, reprogramming its metabolism far from where the pathogen is actually attacking. Such systemic metabolic reprogramming may reduce the overall impact of infection on host tissues, priming distant organs to cope with the physiological disruption that trunk disease causes as it progresses. The finding challenges the conventional focus on the wood alone and suggests that the fate of an infected vine is decided, in part, by how quickly the entire plant can reorganize itself.

The broader implications of this work extend into viticulture and breeding. Grapevine trunk diseases are increasingly concerning in the context of climate change, and with no fully resistant genotypes available, growers currently rely on costly and labor-intensive management practices, including the surgical removal of infected wood and the replanting of dead vines. Understanding the metabolic basis of tolerance could eventually help breeders select for cultivars with the rapid stilbene and oxylipin responses seen in Chardonnay, or guide the development of treatments that stimulate these pathways in susceptible varieties. The study also underscores that fungal isolate matters as much as host cultivar, which means that breeding and protection strategies may need to account for the local diversity of Botryosphaeriaceae populations in vineyards.

By integrating pathogen colonization data with untargeted metabolomics across three organs, two cultivars, two fungal isolates and multiple time points, the research provides a more integrated view of grapevine responses to Botryosphaeriaceae infection than has previously been available. The work, conducted at the Université de Haute Alsace with plants supplied by INRAE UMR SVQV in Colmar, France, and supported by the French Ministry of Higher Education and Research, demonstrates that tolerance to trunk disease is not a single trait but a dynamic, system-wide chemical performance. As vineyards face mounting pressure from a warming climate and evolving pathogen communities, studies like this one bring the field closer to understanding why some vines endure what destroys others, and how that resilience might one day be engineered or bred into the varieties the wine world depends on.

Subject of Research: Metabolomic responses of tolerant and susceptible grapevine cultivars to infection by the trunk disease fungus Neofusicoccum parvum

Article Title: Whole plant metabolomic analysis reveals contrasted responses in tolerant and susceptible grapevine cultivars to infection with different isolates of Neofusicoccum parvum, a major trunk disease fungus

Article References: Grau, A. L., Lacrampe, N., Goddard, M.-L., & Chong, J. (2026). Whole plant metabolomic analysis reveals contrasted responses in tolerant and susceptible grapevine cultivars to infection with different isolates of Neofusicoccum parvum, a major trunk disease fungus. BMC Plant Biology. https://doi.org/10.1186/s12870-026-09951-3

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09951-3

Keywords: grapevine, Neofusicoccum parvum, Botryosphaeria dieback, grapevine trunk diseases, metabolomics, stilbenes, oxylipins, plant defense, Chardonnay, Gewurztraminer, fungal pathogen, viticulture