Tom2a Allele Resists ToBRFV in Tomato
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Solution Overview
Problem
The rapid spread of Tomato brown rugose fruit virus (ToBRFV) poses a significant threat to tomato production, as existing resistance genes like Tm-1, Tm-2, and Tm-22 are broken, leading to severe symptoms on fruits and difficulty in controlling the virus's transmission.
Innovation Solution
A Solanum lycopersicum plant with a QTL on chromosome 8 containing a resistance-conferring allele of the Tom2a gene, which restricts virus replication and is identified using genetically linked markers, providing true resistance to ToBRFV.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing resistance genes (Tm-1, Tm-2, Tm-22) are used to protect tomato plants, then resistance to tobamoviruses is provided, but the resistance is broken by ToBRFV leading to severe fruit symptoms
Solution Approach 1:
The invention changes the genetic parameter by introducing a new resistance gene Tom2a from Solanum pimpinellifolium that has different resistance properties. This gene provides resistance to ToBRFV where the traditional Tm-1, Tm-2, and Tm-22 genes fail, thereby changing the resistance parameter to effectively combat the new virus strain without causing severe fruit symptoms
Solution Approach 2:
The resistance mechanism is segmented by identifying and transferring a specific resistance gene Tom2a from a wild relative Solanum pimpinellifolium into cultivated tomato. This segmentation allows the resistance trait to be separated from other genetic material and precisely introduced through marker-assisted breeding, providing targeted resistance without introducing unwanted traits
2Reliability
If virus transmission is controlled through conventional methods, then some protection is achieved, but rapid spread through vectors and sap transmission continues
Solution Approach 1:
The invention applies preliminary action by incorporating resistance genes into tomato plants before virus exposure occurs. The Tom2a gene is introgressed into breeding lines in advance, creating pre-resistant varieties that can withstand virus transmission attempts by vectors and sap contact, thereby preventing yield loss before it occurs
Solution Approach 2:
The invention uses molecular markers as cheap, rapid detection tools that enable quick identification of resistant plants during breeding. These markers provide a disposable, efficient method to screen large numbers of plants without complex procedures, accelerating the development of resistant varieties that protect productivity
3Reliability
If QTL with Tom2a allele is introduced into Solanum lycopersicum, then true resistance to ToBRFV is achieved, but breeding complexity increases
Solution Approach 1:
The invention uses molecular markers as intermediaries to bridge the gap between the Tom2a resistance gene and the breeding process. These markers serve as reliable indicators that allow breeders to track and select plants carrying the resistance allele without complex phenotypic testing, simplifying the breeding process while ensuring true resistance
Solution Approach 2:
The invention replaces mechanical/phenotypic selection methods with molecular marker-based selection. Instead of visually inspecting plants for resistance traits or performing complex genetic analyses, breeders use DNA markers to directly identify plants carrying the Tom2a allele, substituting a simpler, more accurate molecular detection system
Data Source
AI summary
The invention relates to a Solanum lycopersicum plant that is resistant to ToBRFV, which plant comprises a QTL on chromosome 8 between SEQ ID NO: 1 and 4. The presence of the QTL on chromosome 8 is identified by use of at least one of the markers selected from the group consisting of the SNP presented in SEQ ID NOS: 1 to 42. The QTL is present in the genome of a Solanum lycopersicum plant representative seed of which was deposited with the NCIMB under deposit number NCIMB 43637.