Pollen EMS Mutagenesis for High-Efficiency Maize Variant Creation
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Solution Overview
Problem
Current pollen mutagenesis methods in maize have low mutation efficiency, limiting the generation of independent mutant alleles, which hinders the discovery and interpretation of genetic variants and increases the cost and complexity of mutant recovery.
Innovation Solution
A method involving multiple rounds of pollen EMS mutagenesis, combined with seed mutagenesis, to enhance mutation frequency and maintain mutations in a heterozygous condition, using chemical mutagens like EMS and other agents to increase mutation density and independence across generations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pollen mutagenesis is performed in maize using EMS, then mutations can be generated in the M1 generation, but the mutation efficiency is very low (about 1 out of 1,000 gametes)
Solution Approach 1:
The patent applies preliminary action by treating pollen with EMS mutagen before fertilization occurs. The pollen is exposed to the mutagen in advance, allowing mutations to be introduced into the gametes before they participate in reproduction. This preliminary mutagenesis of pollen enables mutations to be present in the M1 generation rather than requiring multiple generations to recover mutant phenotypes, thereby improving both mutation efficiency and frequency.
2Quantity of substance
If seed mutagenesis is used in maize, then mutations are generated in both ear and tassel primordial cells independently, but this requires propagating through the M3 generation to recover recessive mutations, increasing time and expense
Solution Approach 1:
The patent applies preliminary action by performing mutagenesis on pollen before fertilization, so that mutations are introduced into the gametes in advance. This allows recessive mutations to be revealed in the M1 or M2 generation rather than requiring propagation to the M3 generation, significantly reducing the time and resources needed for mutant recovery while maintaining the ability to generate multiple independent mutations.
Solution Approach 2:
The patent extracts the mutagenesis step from the seed treatment approach and applies it specifically to pollen. By separating the mutagenesis action from whole seed treatment and focusing it on the male gametes, the method achieves independent mutation generation in a controlled manner that reveals recessive mutations earlier without requiring extensive multi-generational propagation.
3Adaptability or versatility
If pollen mutagenesis is performed to generate independent mutations, then targeted mutant screens can be conducted, but the low mutation frequency acts as a deterrent increasing cost and complexity
Solution Approach 1:
The patent applies parameter changes by modifying the concentration and exposure time of EMS mutagen treatment of pollen to optimize mutation frequency. By adjusting these chemical treatment parameters, the method achieves sufficient mutation density to enable targeted mutant screens and non-complementation screens while maintaining a streamlined protocol that reduces complexity compared to traditional seed mutagenesis requiring multi-generational propagation.
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 mutation frequency, allowing for the creation of a highly mutated seed library with increased mutation density, facilitating the identification and propagation of desired genetic variants, reducing the need for additional generations and improving the efficiency of mutant recovery and genetic analysis.
Implementation Method 1
EMS is an alkylating agent that reacts mainly with the guanine (G) base in the DNA to change it to O-6-ethylguanine
Data Source
AI summary
Presented herein are methods for creating a desired genetic variant at a high efficiency from a seed. In one aspect, a method for creating a desired genetic variant at a high efficiency from a seed is presented. The method involves subjecting isolated pollen to a chemical mutagen to produce a first generation seed, planting the first generation seed in (n) plots to produce first generation plants, recovering mutagenized pollen from the first generation plants, pollinating a female parent with the recovered mutagenized pollen to produce a next generation seed, subjecting pollen from the next generation seed to mutagenesis to pollinate the first generation plant, resulting in a new next generation seed, planting the new next generation seed to produce a new next generation plant, and subjecting pollen from the new next generation plant to mutagenesis to pollinate the new next generation plant.