Haploid Inducer Lines for Maize Embryo Selection
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Solution Overview
Problem
The process of obtaining homozygous plants is inefficient due to the need for multiple generations of self-pollination and segregation analysis, which requires significant labor and time.
Innovation Solution
The development of methods to identify and produce haploid plants and seeds by preventing the growth of diploid embryos, using haploid inducer lines with specific polynucleotides that prevent pollen fertilization and embryo lethality, allowing for the production of doubled haploid plants that are considered homozygous.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple generations of self-pollination are performed to obtain homozygous plants, then homozygous plants can be produced, but the time and labor required increase significantly
Solution Approach 1:
The patent applies preliminary action by using haploid inducer lines that are prepared in advance with specific polynucleotides (such as barnase and barstar) that will selectively eliminate diploid embryos before they can develop. This pre-prepared system eliminates the need for multiple generations of self-pollination, directly producing homozygous doubled haploid plants in a single generation.
Solution Approach 2:
The patent extracts the essential function of obtaining homozygous plants by using haploid induction followed by chromosome doubling. Instead of extracting through multiple self-pollination generations, the invention extracts diploid embryos using polynucleotide-based selective ablation, leaving only haploid embryos that can be doubled to produce homozygous plants efficiently.
2Reliability
If multiple generations of self-pollination are performed to obtain homozygous plants, then homozygous plants can be produced, but the labor required increases significantly
Solution Approach 1:
The patent applies self-service by using the plant's own genetic system (haploid inducer lines with polynucleotides) to automatically eliminate diploid embryos without requiring human intervention for hand pollination. The barnase/barstar system self-regulates to selectively ablate diploid embryos, eliminating the need for manual pollination operations.
Solution Approach 2:
The patent replaces the mechanical system of hand pollination with a biochemical system using polynucleotides (barnase and barstar) that selectively eliminate diploid embryos through molecular mechanisms. This substitution eliminates the need for manual pollination labor while achieving the same homozygous plant production goal.
3Productivity
If haploid embryos are produced by preventing diploid embryo growth, then efficiency of doubled haploid production increases, but the complexity of the selection process increases
Solution Approach 1:
The patent applies universality by designing haploid inducer lines that perform multiple functions simultaneously: they produce haploid embryos, selectively eliminate diploid embryos through polynucleotide expression, and enable efficient doubled haploid production. The barnase/barstar system serves both as a selection mechanism and as a productivity enhancement tool.
Solution Approach 2:
The patent applies parameter changes by modifying the genetic parameters of the inducer line through specific polynucleotide insertions (barnase and barstar genes). These genetic parameter changes enable the system to distinguish between haploid and diploid embryos at the molecular level, allowing for efficient selection without complex physical or visual differentiation systems.
Data Source
AI summary
Methods of selecting haploid embryos are disclosed. Methods of producing haploid embryos and non-viable diploid embryos on a plant are provided. Methods for selecting haploid embryos produced from haploid inducer maize lines are provided. Methods for producing improved maize haploid inducer lines are disclosed. Maize haploid inducer lines comprising transgenes causing ablated or abnormal diploid embryos are disclosed.