Maize Microspore Reprogramming for Doubled Haploid Production
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Solution Overview
Problem
Current methods for producing doubled haploid plants in maize are recalcitrant to microspore isolation and in vitro tissue culture, limiting the efficiency of developing recombinant inbred lines.
Innovation Solution
A method involving the use of embryogenic microspores modulated by embryogenesis-inducing factors, such as polypeptides and compounds, to promote haploid plant embryo formation, followed by chromosome doubling to generate doubled haploid plants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional pollination control and self-fertilized line propagation methods are used, then genetic purity is maintained, but the time required for developing recombinant inbred lines is prolonged
Solution Approach 1:
The patent changes the ploidy parameter of the plant cells by inducing haploid embryos from microspores and then doubling chromosomes to create doubled haploids. This parameter change bypasses the traditional time-consuming process of multiple generations of self-fertilization while maintaining genetic purity, as the doubled haploid plants are completely homozygous in one generation rather than requiring repeated inbreeding
Solution Approach 2:
The patent performs chromosome doubling as a preliminary action immediately after haploid embryo formation, creating doubled haploid plants that are already completely homozygous. This preliminary chromosome doubling eliminates the need for subsequent generations of self-fertilization required in traditional methods, significantly reducing the time for developing recombinant inbred lines while maintaining genetic purity
2Productivity
If microspore isolation and in vitro tissue culture methods are used, then productivity is improved, but the difficulty of operation increases due to recalcitrance
Solution Approach 1:
The patent uses an intermediary approach by utilizing the natural developmental transition of microspores to haploid embryos within the anther context, rather than requiring complete microspore isolation. The in vitro culture system serves as an intermediary environment that supports this developmental transition, bypassing the technical difficulties of microspore isolation while maintaining high productivity in doubled haploid production
Solution Approach 2:
The patent extracts the essential requirement from traditional methods by taking out the need for complete microspore isolation. Instead, it cultures entire anthers or anther segments in vitro, extracting only the necessary component (the microspore-containing tissue) while leaving the protective anther structure intact, thereby simplifying the operation while maintaining productivity
Data Source
AI summary
Plant cell fate and development is altered by treating cells with cellular reprogramming factors. Embryogenesis inducing morphogenic developmental genes are used as cellular reprogramming factors, specifically comprising polypeptides or polynucleotides encoding gene products for generating doubled haploids or haploid plants from gametes. Maize microspores treated by contacting the isolated cells with an exogenous purified, recombinant embryogenesis inducing morphogenic developmental gene polypeptide results in embryogenesis. The gametes of a maize plant develop into embryoids when transformed with a genetic construct including regulatory elements and structural genes capable of acting in a cascading fashion to alter cellular fate of plant cells. Developmental morphogenic proteins expressed from a genetic construct are used for ex situ treatment methods and for in planta cellular reprogramming.