Haploid Induction via Mutated IG and CENH3 Genes
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Solution Overview
Problem
Current methods for generating haploid plants in crops like maize and rapeseed have low haploid induction rates, particularly for paternal haploid induction, limiting the efficiency of breeding and genetic improvement.
Innovation Solution
Combining a mutated indeterminate gametophyte (ig) gene with a mutated centromere or kinetochore gene, such as CENH3, to enhance haploid induction rates, specifically in maize, sorghum, and rapeseed, by crossing plants with these genetic modifications to achieve higher paternal haploid induction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a mutated indeterminate gametophyte (ig) gene is used for haploid induction, then paternal haploid induction is enabled, but the haploid induction rate remains low (up to 3.6% in maize)
Solution Approach 1:
The patent combines the mutated ig gene with a mutated centromere or kinetochore gene (such as CENH3) to create a composite haploid inducer system. This merging of two genetic modifications synergistically increases the haploid induction rate from the natural spontaneous frequency of about 1 per 80,000 to significantly higher frequencies, resolving the contradiction between enabling paternal haploid induction and achieving sufficient induction rates.
Solution Approach 2:
The patent modifies the genetic parameters of the plant by introducing specific mutations in the ig gene and centromere/kinetochore gene. These parameter changes in the genetic code enable the plant to function as an effective haploid inducer with improved induction rates, transforming the natural low-frequency event into a controlled breeding tool.
2Productivity
If transgenic 'tailswap' inducer or non-transgenic inducer with mutated endogenous CENH3 gene(s) is used, then haploid induction reaches up to 10% in Arabidopsis, but the rate drops to much lower levels (up to 3.6% in maize, up to 2% in rapeseed)
Solution Approach 1:
The patent identifies and utilizes the mutated ig gene as a universal haploid induction tool that functions across multiple species including maize, sorghum, and rapeseed. By combining this universally applicable ig mutation with species-specific centromere or kinetochore genes, the system achieves high haploid induction rates in diverse crop plants, making the approach adaptable across different species while maintaining high productivity.
3Productivity
If the ig gene is mutated to induce haploids, then paternal haploid induction is achieved, but only one haploid can be produced per segregating plant
Solution Approach 1:
The combination of mutated ig gene with mutated centromere or kinetochore gene creates a synergistic effect that enables multiple haploids to be produced from a single segregating plant. The mutated centromere or kinetochore gene enhances the efficiency of the ig mutation, allowing one plant to serve as a source for multiple haploid progeny, thereby increasing productivity without proportionally increasing breeding scheme complexity.
Data Source
AI summary
The present invention relates to plants comprising a polynucleic acid encoding a mutated indeterminate gametophyte (ig) protein and a polynucleic acid encoding a mutated centromere or kinetochore protein, wherein said mutated centromere or kinetochore protein preferably is CENH3. The mutated ig and centromere or kinetochore proteins together result in haploid inducing activity, such as in particular paternal haploid inducing activity. The invention further relates to methods for generating such plants and uses thereof.