Tomato Plant Breeding for High BRIX Without Leaf Necrosis
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Solution Overview
Problem
The introduction of BRIX-increasing alleles from wild tomato relatives into cultivated lines is hindered by the presence of deleterious alleles that cause leaf necrosis, making it difficult to develop tomato plants with improved fruit quality without unacceptable traits.
Innovation Solution
Development of novel molecular markers that allow for the identification and removal of the necrosis allele, enabling the introgression of BRIX-increasing alleles from Solanum pennellii into cultivated tomato lines without the linked necrosis trait through marker-assisted selection (MAS).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If BRIX-increasing alleles are introgressed from wild tomato relatives into cultivated lines, then fruit quality is improved, but leaf necrosis occurs due to linked deleterious alleles
Solution Approach 1:
The patent applies segmentation by dividing the chromosomal region into smaller segments through recombination events. Specifically, it identifies and selects recombinant chromosomal segments that contain the desired BRIX-increasing allele while excluding the linked deleterious necrosis allele. This is achieved by creating multiple breakpoints in the donor DNA segment, effectively segmenting the original linked region into smaller, selectable units that can be precisely introgressed without harmful traits.
Solution Approach 2:
The patent applies the extraction principle by removing the deleterious necrosis allele from the chromosomal segment containing the BRIX-increasing allele. Through marker-assisted selection and identification of recombinant segments, the invention extracts only the beneficial BRIX allele while leaving behind the harmful necrosis allele in the donor parent, thus achieving separation of desirable and undesirable traits.
2Productivity
If marker-assisted selection is used to identify BRIX alleles, then breeding efficiency is improved, but accurate markers are frequently unavailable
Solution Approach 1:
The patent applies preliminary action by pre-identifying and characterizing molecular markers (SNPs) that are linked to the BRIX-increasing allele and the necrosis allele before the breeding process begins. The invention develops a panel of markers flanking the target region, which can be used in advance to screen and select desirable recombinant segments. This preliminary marker development enables efficient marker-assisted selection in subsequent breeding cycles without requiring de novo marker discovery for each breeding program.
3Manufacturing precision
If conventional breeding methods are used to introduce BRIX alleles, then fruit quality improvement is achieved, but large amounts of unnecessary donor DNA are retained
Solution Approach 1:
The patent applies segmentation by identifying and selecting only the minimal necessary donor DNA segment containing the BRIX allele. Through analysis of recombinant chromosomes and identification of breakpoints, the invention isolates the smallest functional segment required for the desired trait, excluding unnecessary flanking donor DNA. This results in more precise introgression with reduced linkage drag and minimal retention of donor genome.
Solution Approach 2:
The patent applies extraction by removing unnecessary donor DNA from the introgressed segment. By identifying the precise boundaries of the BRIX allele and selecting recombinant segments that minimize donor DNA retention, the invention extracts only the essential genetic material needed for fruit quality improvement, leaving behind excessive donor genome sequences that would constitute linkage drag.
Data Source
AI summary
Tomato plants exhibiting fruit with increased BRIX content are provided, together with methods of producing, identifying, or selecting plants or germplasm with an increased BRIX phenotype and lacking undesirable leaf necrosis. Such plants include tomato plants comprising introgressed genomic regions conferring increased BRIX without necrosis. Compositions, including novel polymorphic markers for detecting plants comprising introgressed alleles providing increased BRIX without necrosis, are further provided.