CRISPR Gene Editing for Grape Disease Resistance

The Science of Susceptibility

Traditional plant defense focuses on adding resistance genes. CRISPR enables a revolutionary approach: removing susceptibility genes. Rather than giving grapes weapons against pathogens, we can remove the “doorways” pathogens use to enter.

Powdery Mildew: The MLO Breakthrough

The MLO Gene Discovery

MLO (Mildew Locus O) genes encode proteins that powdery mildew fungi exploit to infect plants. In grapes, MLO proteins act as “susceptibility factors.”

Key insight: Knocking out specific MLO genes makes grapevines resistant to powdery mildew without adding foreign DNA.

Research Milestones

2014: First demonstration of CRISPR in grapevine cells 2016: MLO gene knockout achieved in lab conditions 2019-2023: Greenhouse trials confirm resistance 2023+: Field trials underway (Italy, France, USA)

Current Projects

Italy - CREA/University of Udine:

• Chardonnay MLO knockout
• Strong powdery mildew resistance achieved
• Greenhouse validation complete

France - INRAE:

• Merlot and Chardonnay editing
• Multiple MLO gene targets
• Field trial planning

USA - UC Davis:

• Thompson Seedless (table grape) success
• Wine grape applications developing

Downy Mildew: More Complex Challenge

Why It’s Harder

Downy mildew (Plasmopara viticola) uses different infection mechanisms than powdery mildew:

• Multiple susceptibility genes involved
• Pathogen diversity greater
• Resistance more complex to engineer

Research Approaches

Susceptibility gene targets:

• DMR (Downy Mildew Resistance) genes
• Cell wall modification genes
• Immune response regulators

Current status: Earlier stage than powdery mildew; active research in Italy, France, Germany

Botrytis: Targeted Modification

Dual Nature Challenge

Botrytis cinerea is both:

• Harmful: Grey rot (wet conditions)
• Beneficial: Noble rot for Sauternes, Tokaj

Selective Approach

Research aims for:

• Reduce grey rot susceptibility
• Potentially preserve noble rot capability
• Complex regulatory genes involved

Italian Research Leadership

Why Italy Leads

1. Regulatory clarity: TEA (Tecniche di Evoluzione Assistita) framework
2. Research infrastructure: CREA, Edmund Mach, universities
3. Variety diversity: Many indigenous varieties to protect
4. Industry support: Consortium funding

Key Italian Projects

Glera (Prosecco):

• Prosecco DOC consortium-supported
• Powdery mildew focus
• Field trials authorized 2023

Sangiovese:

• Chianti, Brunello importance
• Multiple research groups
• Downy and powdery targets

Nebbiolo:

• Barolo, Barbaresco critical variety
• Edmund Mach research
• Complex phenolic preservation focus

Corvina:

• Amarone production
• Disease resistance without affecting drying process

French Programs

INRAE Projects

Merlot:

• Bordeaux consortium interest
• MLO knockout research
• Bordeaux AOC implications

Chardonnay:

• Champagne and Burgundy applications
• Multiple research groups
• Regulatory pathway development

Champagne Consideration

Comité Champagne monitoring developments for potential future adoption in Champagne AOC.

Technical Challenges

Grape-Specific Difficulties

Challenge	Description
Long generation	3-5 years to flowering
Transformation efficiency	Low success rate in grapevines
Genotype specificity	Protocols vary by variety
Phenolic complexity	Must maintain wine quality
Off-target effects	Unintended edits possible

Quality Assurance

Critical requirement: Edited vines must produce identical wine to unedited parent.

Verification:

• Chemical analysis
• Sensory evaluation
• Multi-year trials

Field Trial Status (2026)

Active Trials

Country	Varieties	Focus
Italy	Glera, Sangiovese, Chardonnay	Powdery mildew
France	Merlot, Chardonnay	Powdery mildew
Germany	Research varieties	Multiple diseases
USA	Chardonnay, table grapes	Powdery + Pierce’s

Expected Results

• Disease resistance confirmation
• Wine quality assessment
• Agronomic performance
• Long-term stability

Path to Commercial Use

Regulatory Milestones Needed

1. EU regulation finalization (Category 1 classification)
2. Member state implementation
3. AOC/DOC rule amendments
4. Industry acceptance
5. Consumer communication

Optimistic Timeline

• 2027-2028: Regulatory clarity
• 2028-2030: First varietal approvals
• 2030-2035: Limited commercial release
• 2035+: Broader adoption

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Last Updated: January 7, 2026