Melon Plants CYSDV Tolerance Recombinant Introgression
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Solution Overview
Problem
Cultivated melon lines face challenges in introducing disease tolerance alleles for cucurbit yellow stunt disorder virus (CYSDV) due to the introduction of deleterious traits, such as reduced fruit set and yield, and the lack of accurate markers for marker-assisted selection (MAS) in plant breeding.
Innovation Solution
Development of recombinant introgressions on chromosome 9 that confer improved tolerance to CYSDV without detrimental effects on fruit yield or plant vigor, using specific alleles and markers like NU0218332, NU0219432, and NCMEL009102569, allowing for homozygous or heterozygous deployment and enabling marker-assisted selection to track and introduce these traits into cultivated melon lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If disease tolerance alleles are introduced into cultivated melon lines, then tolerance to cucurbit yellow stunt disorder virus is improved, but fruit set and yield are reduced
Solution Approach 1:
The patent applies segmentation by dividing the chromosomal region containing the disease tolerance allele into smaller segments through recombination. Specifically, it isolates the desired tolerance allele from its original genomic context by creating recombinant introgressions that contain only the essential tolerance region while excluding linked deleterious alleles. This is achieved through marker-assisted selection of recombinant chromosomes that have undergone crossing over within the introgression region, thereby separating the beneficial tolerance trait from harmful linked traits.
Solution Approach 2:
The patent extracts the disease tolerance allele from its original genetic background by selecting recombinant introgressions that contain the tolerance allele but have had surrounding genomic regions removed through recombination. The process involves identifying and selecting plants that have undergone recombination events within the introgression region, thereby extracting the essential tolerance function while leaving behind the linked deleterious alleles that cause reduced fruit set and yield.
2Measurement precision
If marker-assisted selection is used to select plants based on genetic markers, then selection accuracy is improved, but accurate markers for disease tolerance are frequently unavailable
Solution Approach 1:
The patent uses genetic markers as intermediary tools to indirectly select for disease tolerance alleles. Since direct measurement of disease tolerance in the field is complex and time-consuming, the invention employs molecular markers that are genetically linked to the tolerance allele as proxies. These markers serve as intermediaries that can be easily assayed in the laboratory to identify plants carrying the desired tolerance allele, thereby enabling accurate selection without directly phenotyping disease resistance.
Solution Approach 2:
The patent replaces traditional mechanical/phenotypic selection methods with molecular-based selection. Instead of visually assessing disease tolerance in the field or through complex phenotypic tests, the invention uses DNA-based marker analysis to identify plants carrying the tolerance allele. This substitution of molecular mechanisms for mechanical phenotyping enables more accurate, faster, and earlier selection of desirable traits.
3Manufacturing precision
If recombination is used to separate tolerance alleles from deleterious traits, then trait purity is improved, but breeding complexity increases
Solution Approach 1:
The patent employs feedback through marker-assisted selection to guide the breeding process. By continuously monitoring the presence of the tolerance allele and the absence of deleterious alleles using molecular markers, breeders can make informed decisions at each generation. The feedback from marker analysis allows for selective breeding of recombinant plants that achieve the desired separation of traits, thereby managing breeding complexity through information-driven decision making rather than trial and error.
Data Source
AI summary
The present disclosure provides melon plants exhibiting tolerance to cucurbit yellow stunt disorder virus (CYSDV) and lacking negative traits associated with CYSDV tolerance such as increased fruit size and reduced fruit set. Such plants may comprise novel introgressed genomic regions associated with disease tolerance. In certain aspects, compositions, including novel polymorphic markers and methods for producing, breeding, identifying, and selecting plants or germplasm with a disease tolerance phenotype are provided.