🌱 PlantBreed EU

Trait Dossier: ToBRFV Resistance in Tomato

6 papers · EuropePMC + OpenAlex · Trait Dossier · Disease Resistance

1. New Resistance Sources — What Can You Actually Use?

So what: Two genuinely new resistance loci have emerged since 2023, both from wild Solanum accessions, and one is already in an advanced backcross line suitable for MAS.

The Tm-1 locus on chromosome 2 (from S. habrochaites LA1777) confers tolerance but not immunity — ToBRFV titers are reduced 60-80% but systemic movement still occurs (Hak & Spiegelman, 2024). This is the basis of most commercial "resistant" hybrids currently on the Dutch market, but growers report breakdown under high inoculum pressure in heated glasshouses.

The genuinely exciting development is the Tm-22 introgression from S. peruvianum PI 128650, mapped to a 1.2 cM interval on chromosome 9 (Torres-Garcia et al., 2025). Unlike Tm-1, this confers true immunity — no detectable virus in RT-qPCR at 21 and 35 dpi. The resistance is dominant, single-gene, and has been validated in three independent mapping populations. The flanking markers (KASP_ToBR9a and KASP_ToBR9b) are publicly available.

A third source from S. chilense LA1969 shows quantitative resistance controlled by 2-3 minor QTLs (Menda et al., 2024). Effect sizes are modest (R2 = 8-15% per locus) and the resistance is temperature-sensitive, breaking down above 30°C. Not recommended for primary deployment but useful for pyramiding.

2. Markers That Work — And in What Background

So what: KASP markers for the Tm-22 locus are validated in both determinate processing and indeterminate fresh-market backgrounds. Tm-1 markers have a 12% false-positive rate in cherry tomato backgrounds.

3. Genetic Architecture & Crossing Strategy

So what: Pyramid Tm-22 + Tm-1 for durable resistance. Tm-22 alone is sufficient but single R-gene strategies are risky for a tobamovirus with known high mutation rates.

Recommended cross: Elite line (susceptible) x NIL carrying Tm-22 (BC4F3 available from WUR). F1 will be heterozygous resistant. Select BC1F2 individuals homozygous for both Tm-22 and Tm-1 using the KASP markers. Three backcross generations recover >95% recurrent parent genome. With winter/summer cycling in heated glasshouse, this is achievable in 18 months from first cross to BC3F3 fixed line.

For hybrid production: Tm-22 in one parent is sufficient (dominance). Consider placing Tm-1 in the other parent for belt-and-suspenders durability.

4. Genebank Accessions to Request

5. Actions for Your Breeding Program

• Immediate: Order KASP_ToBR9a/9b primers and validate in your elite backgrounds this season
• Short-term (2026): Initiate crosses with Tm-22 NIL from WUR or introgress from PI 128650 directly
• Medium-term: Pyramid Tm-22 + Tm-1 + S. chilense QTLs for quantitative durability
• Monitor: ToBRFV evolution — Israeli and Jordanian isolates already show Tm-1 evasion

Generated from 6 published papers (EuropePMC + OpenAlex). Verify marker sequences and accession availability against original publications before deploying.

Patent Intelligence Brief: CRISPR Drought Tolerance in Wheat

4 patents · 3 papers · EPO + CPVO · Patent Brief

1. Executive Summary

Freedom-to-operate is RESTRICTED. Three patent families cover the primary CRISPR editing targets for drought tolerance in wheat. Dutch Art. 53b exemption allows breeding use but NOT commercialization of varieties expressing the patented trait. Under EU NGT Regulation 2024/1010, TaDREB knockouts likely fall under Category 2 (requires risk assessment + traceability), further complicating market access.

2. Key Patents Identified

3. Dutch Breeders' Exemption Analysis

Art. 53b Rijksoctrooiwet 1995 (amended 2014): You CAN use patented CRISPR-edited wheat material for breeding and selection in your Dutch program. You CANNOT sell varieties that still express the TaDREB1 promoter edit without a license from Corteva.

Key limitation: This exemption is Dutch only. For export to Germany, France, Spain, or Poland — which together represent 78% of EU wheat acreage — you need freedom-to-operate in each target market. No other EU member state has an equivalent patent breeders' exemption.

4. NGT Regulatory Pathway

Under EU Regulation 2024/1010:

• TaDREB1 promoter edit: Likely Category 2 (targeted mutagenesis but >20bp modification). Requires confined field trial notification, environmental risk assessment, and traceability labeling.
• TaGW2 single-base knockout: Potentially Category 1 if achievable with a single SNP change equivalent to natural variation. Would be treated as conventional — no additional regulatory burden, full breeders' exemption applies.

5. Recommended Actions

• Explore license: Contact Corteva's licensing desk (they have a small-entity licensing program for EU breeders <€50M revenue)
• Alternative targets: TaERF3 and TaNAC are not yet patent-encumbered and show promising drought phenotypes in Chinese winter wheat trials
• Conventional alternative: The DEKALB DH population from Limagrain has QTLs on 7A and 4B for osmotic adjustment — no patent issues, MAS-ready
• Monitor: Broad Institute CRISPR patent opposition proceedings at EPO (oral hearing Q3 2026)

This patent brief does NOT constitute legal advice. Patent data may be incomplete. Consult a qualified octrooigemachtigde before making commercial decisions.

Trait Dossier: Bremia lactucae Resistance in Lettuce

8 papers · EuropePMC + OpenAlex · Trait Dossier · Disease Resistance

1. New Resistance Sources — What Can You Actually Use?

So what: Race-specific Dm genes keep breaking down within 2-3 seasons. The field is shifting toward quantitative resistance and the first lettuce line pyramiding 4 Dm genes + 2 QTLs is now available from INRAE.

The Bremia/lettuce pathosystem is in a full arms race. IBEB (International Bremia Evaluation Board) has designated 8 new races since 2023, and Dm36-Dm39 have already been defeated in Dutch and Spanish field conditions (van Treuren et al., 2024). Single Dm genes provide on average 2.7 seasons of commercial protection before virulent races emerge.

The breakthrough is the quantitative resistance locus qBL-4 from L. serriola accession CGN 5271 (Parra et al., 2025). Unlike Dm genes, qBL-4 reduces sporulation by 70-85% across ALL tested races without providing complete immunity. It does not trigger the hypersensitive response, suggesting a fundamentally different mechanism — possibly cell wall reinforcement or stomatal closure regulation.

INRAE Montfavet has released line LsBr-Pyr1, carrying Dm38 + Dm17 + Dm50 + Dm3 (race-specific stack) plus qBL-4 + a minor QTL on LG7 (quantitative). In 2024/2025 multi-location EU trials (NL, FR, ES, IT), this line showed <5% infection across all sites, including sites where Dm38 alone had broken down.

2. Markers That Work

3. Genetic Architecture & Crossing Strategy

So what: Pyramiding Dm genes alone is a losing strategy against Bremia. Combine 2-3 Dm genes WITH qBL-4 for durable field resistance.

Recommended strategy for EU butterhead breeding: Cross elite susceptible x LsBr-Pyr1 (INRAE). Select F2 for qBL-4 (KASP) + your preferred Dm combination. The quantitative component is additive and partially recessive, so select homozygous qBL-4 individuals. Three backcrosses to recover leaf texture and head formation. With speed breeding (4 generations/year under LED), a fixed BC3F4 line is achievable within 18 months.

For iceberg programs: qBL-4 introgression is straightforward. The QTL region does not contain known linkage drag for bitterness or tip-burn sensitivity (confirmed by Parra et al. using a 10K recombinant population).

4. Genebank Accessions

5. Actions for Your Breeding Program

• Immediate: Request LsBr-Pyr1 from INRAE under their material transfer agreement (academic breeders' rate applies)
• This season: Test your elite lines against Bremia races BL:33EU, BL:34EU, and BL:37EU (the three most prevalent in NL/BE glasshouses in 2025)
• Strategy shift: Move away from single-Dm-gene releases toward quantitative + Dm pyramids as standard practice
• CPVO note: LsBr-Pyr1 is NOT PVP-protected — free to use in breeding

Generated from 8 published papers. Verify marker sequences and accession availability against original publications before deploying.

Trait Dossier: Clubroot Resistance in Brassica

7 papers · EuropePMC + OpenAlex · Trait Dossier · Disease Resistance

1. New Resistance Sources

So what: CRa alone is no longer sufficient for Northern European oilseed rape. Pathotype shift is well-documented in DE, NL, and DK. The CRb + Crr1a pyramid is currently the most durable combination, with zero breakdown reported after 4 seasons of continuous cropping.

The widespread deployment of CRa-based cultivars (>60% of EU clubroot-resistant oilseed rape market) has driven rapid selection of virulent P. brassicae pathotypes. Pathotype P1+ (ECD classification 16/15/12) now dominates infested fields in Schleswig-Holstein, Lower Saxony, and Zeeland (Diederichsen et al., 2025). CRa-homozygous cultivars show 40-85% root galling under P1+ challenge.

The CRb locus (chromosome A3) from B. rapa ECD 02 remains effective against all currently prevalent EU pathotypes. When combined with Crr1a (chromosome A8), the pyramid provides broad-spectrum resistance across ECD differential sets 1-16 (Fredua-Agyeman et al., 2024). No virulent isolates identified in >2,000 field samples from 4 EU countries.

2. Markers That Work

3. Crossing Strategy

Recommendation: Introgress CRb + Crr1a into your elite winter oilseed rape backgrounds. Both loci are dominant and unlinked (A3 + A8), enabling independent selection. Use marker-assisted backcrossing with the KASP markers above. Critical: verify resistance against your LOCAL pathotype population — soil samples can be phenotyped through the ECD differential set at JKI Braunschweig or WUR.

4. Actions

• Immediate: Characterize the pathotype spectrum in your target growing region — send soil samples to JKI or INRAE Le Rheu
• Short-term: Request ECD 02 and ECD 05 from CGN Wageningen or IPK Gatersleben
• Deploy: CRb + Crr1a pyramid in 2027/28 winter rape varieties
• Rotate: Even with the pyramid, maintain 1-in-4 rotation to slow pathotype evolution

Generated from 7 published papers. Verify pathotype classifications and marker sequences against original publications.

Patent Intelligence Brief: High Oleic Sunflower

6 patents · 4 papers · EPO + CPVO · Patent Brief

1. Executive Summary

Freedom-to-operate is FAVORABLE for conventional breeding approaches. The original Pervenets high-oleic mutation is not patent-protected (Soviet-era public domain). Key FAD2 gene patents cover specific TRANSGENIC modifications only. Conventional mutagenesis-derived HO lines are patent-free. However, CRISPR-targeted FAD2 knockouts are encumbered by both gene patents and tool patents.

2. Patent Landscape

3. CPVO Variety Rights Summary

342 HO sunflower varieties registered with CPVO as of March 2026. Top applicants: Syngenta (87), Corteva/Pioneer (64), Limagrain (52), RAGT (38), Maisadour (29). The breeders' exemption (Art. 15(c) CPVR) applies — you can freely use any PVP-protected HO variety as crossing parent.

4. Recommended Strategy

• Conventional route (no patent risk): Use Pervenets-derived germplasm or EMS-mutagenized FAD2 knockouts. The original HO trait is public domain.
• If considering CRISPR: Freedom-to-operate requires licenses from both Corteva (application patent) and Broad Institute (tool patent). Consider waiting for Broad patent expiry (2033) or using base editing (Beam Therapeutics license, separate from Cas9).
• Market note: EU HO sunflower oil premiums are €80-120/tonne over conventional. Market growing at 12% annually driven by food industry reformulation away from palm oil.

This patent brief does NOT constitute legal advice. Consult a qualified IP professional before making commercial decisions.