Haploid Induction via Mutated MATRILINEAL Gene in Maize
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Solution Overview
Problem
The existing methods for inducing haploid seeds in maize are limited by low haploid induction rates, which restrict the production of doubled haploid inbreds, and the genetic factors responsible for haploid induction in maize have not been clearly identified.
Innovation Solution
The use of specific nucleic acid molecules, such as those encoding a patatin-like phospholipase 2A gene with a frameshift mutation, and RNAi constructs to regulate haploid induction in maize plants, allowing for the identification and manipulation of haploid-inducing traits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If standard haploid inducer lines (e.g., Stock 6) are used, then haploid induction can be achieved, but the induction rate is low (1-3%)
Solution Approach 1:
The patent modifies the genetic parameters of the inducer line by introducing transgenes (e.g., ZmD23, ZmCYP707A1) and creating specific mutations (e.g., in the MTL gene) to change the induction rate from 1-3% to over 50%, thereby resolving the contradiction between achieving induction and maintaining high induction rates
Solution Approach 2:
The patent creates copies of specific genetic elements (transgenes, mutated alleles) that are responsible for high induction rates and introduces them into different genetic backgrounds, allowing the high-induction phenotype to be replicated across multiple lines with consistent performance
2Manufacturing precision
If self-pollination is used to develop homozygous inbreds, then homozygosity can be achieved, but the process is time-consuming and expensive
Solution Approach 1:
The patent utilizes a phase transition in chromosome number (from diploid to haploid) to accelerate the breeding process. By inducing haploid embryos that develop into haploid plants, then doubling chromosomes to create immediately homozygous diploid plants, the patent eliminates the need for multiple generations of self-pollination, reducing time from years to months while maintaining complete homozygosity
3Quantity of substance
If the volume of doubled haploid inbreds is increased, then more material is produced, but the low induction frequency limits production
Solution Approach 1:
The patent changes the genetic parameters of the inducer system by introducing specific transgenes and mutations that increase induction frequency from 1-3% to over 50%, thereby enabling large-scale production of doubled haploid inbreds and resolving the contradiction between quantity produced and induction frequency
Data Source
AI summary
Provided here are methods of using a mutated patatin-like phospholipase IIα (“pPLAIIα,” renamed here MATRILINEAL) to induce haploid induction in plants, cloning a pPLAIIα to induce haploid induction in plants, and genetically engineering a plant to contain a mutated pPLAIIα. Also provided are methods of applying topical and spray chemicals, lipids, and RNAi molecules to plants during pollination in order to induce haploid production. Further provided are methods of chemically treating plants during pollination to induce haploids while also reducing embryo abortion and increasing seed set.