Cytotype Transfer for Recalcitrant Maize Transformation
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Solution Overview
Problem
Most elite inbred maize lines are recalcitrant and cannot be transformed with foreign DNA, requiring a lengthy process of backcrossing to introduce transgenic traits, which slows down the development and dissemination of new crop traits.
Innovation Solution
The method involves changing the cytotype of a recalcitrant maize line by pollinating a recipient plant with a transformable NA cytotype using pollen from the recalcitrant plant, resulting in progeny with a higher transformation efficiency and the ability to accept foreign transgenes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If backcrossing is used to introduce transgenic traits into recalcitrant inbred lines, then the transgenic trait can be transferred to the desired line, but the process takes two to three years and requires six or seven generations of backcrossing
Solution Approach 1:
The invention changes the cytotype parameter of the recalcitrant inbred line from NB to NA through pollination with NA cytotype pollen. This parameter change in the mitochondrial genome enables the previously non-transformable line to become transformable, allowing direct transformation without the time-consuming backcrossing process while maintaining the ability to stably integrate transgenic traits into the genome
2Productivity
If direct transformation is attempted on recalcitrant maize lines with NB cytotype, then transformation can be performed quickly, but the transformation efficiency is very low or zero
Solution Approach 1:
The invention changes the cytotype parameter from NB to NA by introducing NA-type mitochondrial DNA through pollination. This parameter change fundamentally alters the transformation efficiency from near-zero to high levels, enabling reliable direct transformation while maintaining speed. The NA cytotype creates a permissive environment for Agrobacterium-mediated transformation that the NB cytotype does not provide
Data Source
AI summary
A method of altering or transferring the cytotype of a plant line. In particular, transferring the cytotype of a transformation-recalcitrant plant line, e.g., a transformation-recalcitrant maize line, from a transformation-recalcitrant cytotype to a transformable cytotype so that the line becomes transformable while preserving its nuclear genome. The newly-transformable line may be produced using methods including backcrossing and/or haploid induction.