Rye Restorer Locus Segmentation for P-CMS Fertility

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Solution Overview

Problem

Current hybrid rye breeding systems using Pampa cytoplasmic male sterility (P-CMS) face challenges due to linkage drag, which results in reduced agronomic performance and yield, particularly when introgressing chromosomal segments containing restorer loci.

Innovation Solution

Development of a plant capable of restoring pollen fertility for P-CMS with reduced or eliminated linkage drag, utilizing tightly linked markers and molecular markers to identify and isolate the restorer genes, specifically the Rfp1 locus, and integrate them into a high-resolution fine map.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chromosomal segments containing restorer loci are introgressed into cultivars, then pollen fertility restoration for P-CMS is achieved, but yield and agronomic performance are reduced due to linkage drag

Engineering Contradiction:
Improvepollen fertility restorationVSAvoidyield
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The restorer locus Rfp1 on chromosome 4R is segmented from surrounding chromosomal regions through precise molecular marker identification. By defining the minimal chromosomal interval containing only the restorer gene (between markers tc256739/ctg32/ctg24met2a5 and tc300731), the invention separates the beneficial restoration function from detrimental linked genes, enabling yield improvement while maintaining fertility restoration capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the restorer locus Rfp1 from the larger chromosomal segment that causes linkage drag. Through marker-assisted selection and fine mapping, the restorer gene is isolated into a minimal introgression segment, removing unwanted linked genes that reduce agronomic performance while preserving the essential pollen fertility restoration function

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If restorer genes are introgressed to restore pollen fertility, then CMS hybrid system functionality is maintained, but negative agronomic traits are introduced through linkage drag

Engineering Contradiction:
Improvepollen fertility restorationVSAvoidnegative agronomic traits
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The chromosomal region is segmented to isolate the restorer locus from surrounding genes that cause negative agronomic effects. By defining precise boundaries using molecular markers (tc256739, ctg32, ctg24met2a5, tc300731), the invention creates a clean introgression segment that contains only the beneficial restorer function without linked detrimental traits

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies local quality by creating a specialized chromosomal segment with specific properties: it contains the restorer locus Rfp1 for pollen fertility restoration while being free from linked genes causing negative agronomic traits. This localized modification allows the restorer region to have unique genetic composition different from the donor parent's genome

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3393234B2Restorer plants
Publication Date: 2025.06.11 KWS SAAT SE & CO KGAA
  • EP3393234B2 patent drawingFigure 1A~1C
  • EP3393234B2 patent drawingFigure 2
  • EP3393234B2 patent drawingFigure 3

AI summary

The invention relates to hybrid cereal crops obtained via the restoration of the pollen fertility for Pampa cytoplasmic male sterility (P CMS), and characterised by a reduced linkage drag. Plants are provided, in particular rye, which, as the male pollen parent, are able to restore the pollen fertility for P CMS. The invention also relates to the nucleic acid molecule that carries the necessary information for the restoration of P CMS, DNA and vectors containing a nucleic acid molecule of this type, corresponding host cells, as well as a protein that can be coded via the nucleic acid molecule, and antibodies directed against same. The invention further relates to methods for producing corresponding hybrid plants and transgenic plants.