ZmPLA1E Gene Mutation for Maize Haploid Induction

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Solution Overview

Problem

Traditional maize breeding methods require 7-8 generations to obtain stable inbred lines, whereas haploid breeding techniques can achieve this in just 2 generations, but the efficiency of parthenogenetic haploid induction in maize is limited by the genetic loci controlling haploid induction rates, which are not fully understood or optimized.

Innovation Solution

The method involves silencing or knocking out the ZmPLA1E gene using CRISPR/Cas9 to enhance parthenogenetic haploid induction in maize, increasing the haploid induction rate by mutating specific genetic loci, thereby accelerating the breeding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional breeding methods are used to obtain stable inbred lines, then the breeding process is simpler and more reliable, but it requires 7-8 generations which significantly increases the time and reduces productivity

Engineering Contradiction:

Improvebreeding efficiencyVSAvoidtime to obtain stable inbred lines

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent changes the genetic parameter by mutating the ZmPLA1E gene (a phospholipase gene) to alter the biological process of embryo development. This mutation induces parthenogenesis where the embryo develops without fertilization, directly producing haploid plants. This parameter change in gene function transforms the breeding timeline from 7-8 generations to just 2 generations, dramatically improving productivity while reducing time loss.

Inventive Principle:

Principle #35Parameter changes

2Loss of time

If parthenogenetic haploid induction is used to accelerate breeding, then the time required is reduced to 2 generations, but the haploid induction rate is limited by unknown genetic loci which reduces reliability

Engineering Contradiction:

Improvetime to obtain stable inbred linesVSAvoidhaploid induction rate

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent extracts and identifies the specific genetic factor (ZmPLA1E gene) that controls haploid induction rate from the complex background of multiple unknown genetic loci. By focusing on this single major gene located in the qhir1 QTL region, the invention isolates the key control element, making the haploid induction process more predictable and reliable while maintaining the time advantage of 2-generation breeding.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent establishes a feedback mechanism by identifying and characterizing the ZmPLA1E gene's role in haploid induction. Through mapping studies and functional analysis, the invention creates a knowledge feedback loop where the genetic basis is understood, allowing breeders to select for high-induction-rate alleles and optimize the induction process, thereby improving reliability while maintaining rapid breeding cycles.

Inventive Principle:

Principle #23Feedback

3Ease of manufacture

If multiple genetic loci control haploid induction rate, then the genetic basis is complex and difficult to optimize, but focusing on single genes simplifies the approach and improves ease of manufacture

Engineering Contradiction:

Improveease of optimizing haploid inductionVSAvoidgenetic basis complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent segments the complex genetic control of haploid induction into distinct functional components: the major effect gene ZmPLA1E and other contributing loci. By identifying ZmPLA1E as the primary control element through QTL mapping and fine-mapping, the invention divides the complex system into manageable parts, allowing breeders to focus on this single gene for optimization while acknowledging other factors, thereby simplifying the breeding approach without ignoring genetic complexity.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly enhances the parthenogenetic haploid induction ability in maize, reducing the time and effort required for breeding by increasing the haploid induction rate, thus improving the efficiency of maize haploid breeding.

Implementation Method 1

Methodology Applied

Scientific EffectCRISPR/Cas9 gene editing:

Data Source

PatentUS11371058B2Maize parthenogenetic haploid-inducing gene ZmPLA1E and application thereof

Publication Date: 2022.06.28 CHINA AGRI UNIV

AI summary

The present invention discloses a maize parthenogenetic haploid-inducing gene ZmPLA1E and application thereof. The present invention utilizes the method of exchanged individual plant progeny tests for the first time, and successfully proves that the ZmPLA1E gene can generate and significantly increase the parthenogenetic haploid induction ability in the process of self-crossing or hybridizing as a male parent with other maize materials after the ZmPLA1E gene is mutated in the coding region. The haploid-inducing gene ZmPLA1E of the present invention is important for the cultivation of high-frequency parthenogenetic haploid inducing lines and the application of haploid technology.