Doubled Haploid Maize Line PHWWD for Transgene Development

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Solution Overview

Problem

The existing maize transformation technology using the Hi-II line is hindered by its hybrid nature, making it difficult to achieve a uniform, homozygous background for transgene development, and it lacks the quality genetics present in elite inbreds, requiring labor-intensive backcrossing to remove deleterious genomes.

Innovation Solution

Development of a novel double haploid maize line, PHWWD, which is homozygous and maintains high transformability and culturability, allowing for efficient introgression of transgenes into an elite background through backcross conversion and transformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If Hi-II maize line is used for transformation, then high transformability and good culturability are achieved, but the hybrid nature prevents uniform homozygous background and requires labor-intensive backcrossing

Engineering Contradiction:
ImprovetransformabilityVSAvoidbackcrossing process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by creating doubled haploid lines that are预先 (in advance) homozygous, eliminating the need for subsequent backcrossing to achieve uniformity. The doubled haploid technology pre-establishes the homozygous background before transformation, so when transformation is performed on these pre-homozygous lines, the transgenic traits can be directly developed without extensive backcrossing to remove hybrid genomes.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If Hi-II maize line is used for transformation, then high transformability is achieved, but elite inbred quality genetics are lacking

Engineering Contradiction:
ImprovetransformabilityVSAvoidelite inbred quality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent merges two previously separate characteristics into one unified solution: it combines the high transformability of Hi-II with the elite inbred quality genetics through the creation of doubled haploid lines. These doubled haploid lines inherit the desirable agronomic traits and homozygosity of elite inbreds while maintaining the high transformability needed for efficient transgene development, thus merging transformation efficiency with elite genetic quality in a single line.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If backcrossing is performed to remove deleterious genomes from Hi-II, then elite inbred quality is improved, but time and labor consumption increase

Engineering Contradiction:
Improveelite inbred qualityVSAvoidbackcrossing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by establishing homozygous doubled haploid lines in advance, which pre-eliminates the need for time-consuming backcrossing to achieve genetic uniformity. The doubled haploid technology creates lines that are already homozygous at all loci, so elite inbred quality is achieved immediately without requiring multiple generations of backcrossing to remove deleterious genomes.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If non-homozygous plants are used for transgene development, then transformation can proceed, but effects of transgene cannot be determined accurately

Engineering Contradiction:
Improvetransformation throughputVSAvoidtransgene effect determination
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies homogeneity by using doubled haploid lines that are completely homozygous at all genetic loci, creating a uniform genetic background. This genetic uniformity ensures that when transgenes are introduced, any observed phenotypic effects can be confidently attributed to the transgenes themselves rather than genetic variability, thus enabling precise determination of transgene effects while maintaining transformation productivity.

Inventive Principle:
Principle #33Homogeneity

Data Source

PatentUS8039719B2Highly transformable elite doubled haploid line-PHWWD
Publication Date: 2011.10.18 PIONEER HI BREED INTERNATIONAL INC

AI summary

A novel double haploid maize line designated PHWWD and seed, plants and plant parts thereof. Methods for producing a maize plant that comprise crossing double haploid maize line PHWWD with another maize plant. Methods for producing a maize plant containing in its genetic material one or more traits introgressed into PHWWD through backcross conversion and/or transformation, and to the maize seed, plant and plant part produced thereby. Hybrid maize seed, plant or plant part produced by crossing the double haploid line PHWWD or a trait conversion of PHWWD with another maize line. Inbred maize lines derived from double haploid maize line PHWWD, methods for producing other inbred maize lines derived from double haploid maize line PHWWD and the inbred maize lines and their parts derived by the use of those methods.