Mutated SL7 Resistance Gene for Broad-Spectrum Lettuce Mildew Control

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Solution Overview

Problem

Current lettuce cultivars face rapid development of new Bremia lactucae races that overcome disease resistance, necessitating the identification of broad-spectrum resistance genes to control downy mildew effectively.

Innovation Solution

Introduction of a mutated SL7 gene in lettuce plants, which encodes for a protein with specific amino acid substitutions, providing dominant resistance to Bremia lactucae races B117 to B135, except B116, B120, B121, B123, and B127, through methods like CRISPR/Cas or mutagenesis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional resistance genes are used in lettuce cultivars, then resistance to downy mildew is provided initially, but the pathogen rapidly mutates to overcome this resistance

Engineering Contradiction:

Improvedisease resistanceVSAvoidduration of resistance effectiveness

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies parameter changes by modifying the SL7 gene sequence to create mutated versions with altered amino acid sequences. Specifically, the invention introduces mutations at positions 38, 40, and 48 of the SL7 protein sequence, creating variants that recognize different Bremia lactucae races. This allows the resistance mechanism to adapt to pathogen evolution while maintaining effectiveness.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by developing a system where multiple SL7 gene variants can be deployed sequentially or simultaneously. As new Bremia races emerge, corresponding mutated SL7 genes can be introduced to maintain resistance, creating a dynamic adaptation system rather than a static resistance solution.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If fungicides are used to control Bremia lactucae, then disease symptoms are suppressed, but the pathogen develops immunity to these chemicals

Engineering Contradiction:

Improvedowny mildew symptomsVSAvoidfungicide effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent replaces the chemical control mechanism (fungicides) with a biological resistance mechanism (mutated SL7 genes). Instead of using external chemicals that the pathogen can develop immunity against, the invention uses genetically engineered resistance proteins that provide durable protection against Bremia lactucae.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If multiple lettuce varieties with different resistance genes are deployed, then resistance to various Bremia races is achieved, but the complexity of resistance management increases

Engineering Contradiction:

Improvespectrum of resistanceVSAvoidresistance management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent achieves universality by creating mutated SL7 gene variants that can recognize multiple Bremia lactucae races. A single mutated SL7 gene construct can provide broad-spectrum resistance against various pathogen races, eliminating the need to deploy multiple different resistance genes and simplifying resistance management.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP3898986B1Lettuce plant resistant to downy mildew and resistance gene

Publication Date: 2026.02.18 ENZA ZADEN BEHEER BV

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AI summary

The present invention relates to a lettuce plant that is resistant to downy mildew, more specifically to a lettuce plant that comprises a mutated gene that confers broad spectrum resistance to oomycetes in lettuce, more specifically Bremia lactucae. Furthermore the present invention relates to a resistance gene and a method for obtaining a lettuce plant that is resistant to downy mildew, wherein the method comprises the step of mutating a gene.