Wheat G-type CMS Restorer Gene Marker Selection
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Solution Overview
Problem
Current methods for hybrid seed production in wheat lack accurate markers for identifying and tracking Rf loci, particularly for G-type cytoplasmic male sterility, which hinders fertility restoration in wheat T. timopheevi cytoplasm, necessitating improved methods for selecting and producing functional restorer genes.
Innovation Solution
The method involves identifying and selecting cereal plants with marker alleles linked to the functional restorer gene for wheat G-type cytoplasmic male sterility located on chromosome 1A, using specific markers such as those listed in SEQ ID NO 2 to SEQ ID NO 10, to restore fertility in progeny plants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional breeding methods are used to identify restorer genes, then the process can be performed without specialized equipment, but the identification accuracy is insufficient and environmental factors affect results
Solution Approach 1:
The patent replaces traditional phenotypic observation methods with molecular marker-based detection systems. Specifically, it uses SSR (simple sequence repeat) markers and SNP (single nucleotide polymorphism) markers to detect restorer gene presence, substituting mechanical/visual assessment with molecular biology techniques that provide higher precision and are independent of environmental conditions.
Solution Approach 2:
The patent introduces molecular markers as intermediary elements that link observable traits to underlying genes. These markers serve as detectable proxies for restorer genes, allowing indirect but accurate identification of gene presence without directly observing gene expression or function, thereby resolving the contradiction between detection accuracy and system complexity.
2Productivity
If phenotypic selection methods are used, then the selection process is simple and direct, but it is dependent on environmental factors and cannot be performed year-round
Solution Approach 1:
The patent replaces field-based phenotypic selection with laboratory-based molecular marker analysis. This substitution enables breeding operations to be conducted in controlled laboratory environments year-round, independent of seasonal variations and environmental conditions, while maintaining selection accuracy through DNA-based detection methods.
Solution Approach 2:
The patent performs marker analysis on young plant samples or even seedling DNA extracts, allowing selection decisions to be made early in the breeding cycle before plants reach flowering stage. This preliminary molecular assessment eliminates the need to wait for phenotypic expression, thereby enabling year-round breeding operations and accelerating selection cycles.
3Measurement precision
If existing markers with larger genetic distance are used, then the marker system is easier to implement, but the tracking accuracy of Rf loci is insufficient
Solution Approach 1:
The patent applies the principle of local quality by selecting markers that are specifically located in close proximity to restorer gene loci on chromosomes. Instead of using any convenient marker, the invention identifies and utilizes markers with small genetic distances (e.g., SSR markers within 5-10 cM, preferably within 2-5 cM of Rf loci), thereby optimizing local tracking accuracy where it matters most for gene identification.
Solution Approach 2:
The patent segments the genome into specific chromosomal regions containing restorer genes and identifies markers within or adjacent to these segments. By dividing the genome into manageable chromosomal regions and selecting markers locally within or near Rf loci, the invention achieves high tracking accuracy while organizing the complex genetic information into structured, implementable marker systems.
Data Source
AI summary
Methods are described for selecting or producing a cereal plant comprising a functional restorer gene for wheat G-type cytoplasmic male sterility and nucleic acids for use therein.