Researchers edited Chardonnay genes to target mildew resistance

Researchers in Italy and the Netherlands reported work on grapevine genome editing aimed at producing Chardonnay and microvine clones with resistance to powdery mildew and downy mildew, two diseases that drive heavy pesticide use in vineyards.

The study was published by IVES OpenScience as an extended abstract in the GiESCO 2017 conference series. The authors said cultivated grapevine, Vitis vinifera, remains highly susceptible to fungal and fungus-like diseases, especially powdery mildew, often called PM, and downy mildew, or DM. Those infections are among the main reasons growers rely on repeated fungicide applications during the season.

The team focused on so-called susceptibility genes in the plant itself. In their report, they said earlier research had already shown the importance of the MLO gene family in grapevine susceptibility to powdery mildew. They also pointed to DMR6, a gene identified in Arabidopsis thaliana as linked to susceptibility to downy mildew, though its role in grapevine had not yet been demonstrated.

Using CRISPR/Cas9, the researchers set out to knock out specific MLO and DMR6 genes while preserving the varietal and clonal identity of the vine. That point is important for wine grapes because traditional breeding for disease resistance often requires crossing Vitis vinifera with other material, which can change traits tied to a recognized variety. Genome editing, by contrast, is being explored as a way to alter a targeted trait without remaking the grape from scratch.

According to the abstract, embryogenic callus from Chardonnay and microvine varieties was transformed through Agrobacterium tumefaciens carrying CRISPR/Cas9 vectors designed to edit those genes. Plants regenerated in vitro from the edited tissue were then sequenced. The sequencing confirmed small insertions and deletions, as well as single nucleotide polymorphisms, at the intended target sites.

The report does not present field performance data or commercial release plans, and it does not say that resistance has already been proven under vineyard conditions. Instead, it describes the generation of edited grapevine material and the confirmation that targeted genetic changes were introduced. The authors framed the work as a step toward producing clones resistant to powdery mildew and downy mildew.

The research was carried out by scientists from the Research and Innovation Centre of Fondazione Edmund Mach in San Michele all’Adige, Italy, and Scienza Biotechnologies in Enkhuizen, the Netherlands. The listed authors are Lisa Giacomelli, Tieme Zeilmaker, Mickael Malnoy, Riccardo Velasco, Roberto Viola, Jeroen Rouppe Van Der Voort and Claudio Moser.

For the wine sector, the potential significance is clear even if practical use remains uncertain. If disease-resistant clones can be developed without changing a grape’s core varietal identity, vineyards could eventually reduce fungicide use, lower some production costs and improve crop health stability in seasons with strong mildew pressure. That could matter for both conventional and sustainability-focused producers, especially in regions where repeated treatments are routine to protect yield and fruit quality.

The work also lands at a time when viticulture faces growing pressure to cut chemical inputs while maintaining consistency in the vineyard. Chardonnay is one of the world’s most widely planted wine grapes, so any successful disease-resistance strategy that keeps its established profile intact would draw attention across the beverage industry. Much will depend on further testing, regulatory treatment of genome-edited vines and whether edited plants can deliver durable resistance without unwanted effects on growth, yield or grape composition.