Plastid-Targeted 6PGDH Fusion Protein for Maize Heat Stress
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Solution Overview
Problem
Current plant breeding methods fail to generate corn varieties that effectively tolerate different weather patterns due to climate change, particularly struggling with increased heat stress and drought, which affects yield and grain quality.
Innovation Solution
Genetic modification of corn to express a fusion protein with a plastid targeting sequence fused in frame with cytosolic 6-phosphogluconate dehydrogenase (6PGDH), allowing the enzyme to import into plant cell plastids, thereby enhancing heat resistance and yield during heat stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional plant breeding methods are used, then yield and grain quality are enhanced, but the ability to tolerate heat stress and drought is insufficient
Solution Approach 1:
The patent modifies the subcellular localization parameter of the 6PGDH enzyme by fusing it with a plastid-targeting sequence, changing its location from cytosol to plastid. This parameter change enables the enzyme to function effectively under heat stress conditions, improving reliability while maintaining productivity
Solution Approach 2:
The patent creates a fusion protein that combines the 6PGDH enzyme with a plastid-targeting sequence, forming a composite molecular structure. This composite approach allows the enzyme to be imported into plastids where it can provide heat stress tolerance, resolving the contradiction between yield enhancement and stress tolerance
2Reliability
If cytosolic 6PGDH is expressed, then enzyme activity is maintained, but heat resistance during grain-fill is insufficient
Solution Approach 1:
The patent introduces a plastid-targeting sequence as an intermediary element that mediates the import of 6PGDH into plastids. This intermediary sequence enables the enzyme to reach its functional destination where it can provide heat resistance, while the enzyme itself maintains its catalytic activity
Solution Approach 2:
The patent changes the spatial dimension of 6PGDH localization from the cytosolic compartment to the plastid compartment. This dimensional relocation places the enzyme in a different cellular environment where it can effectively contribute to heat resistance during grain-fill stages
3Reliability
If genetic modification is implemented, then heat resistance and yield are improved, but regulatory complexity increases
Solution Approach 1:
The patent uses a universal plastid-targeting sequence that can direct multiple different enzymes to plastids. This universal approach simplifies regulatory considerations compared to enzyme-specific targeting methods, as the same targeting sequence can be applied across different genetic modification scenarios
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
The modified corn exhibits increased heat resistance and yield under heat stress conditions without negatively affecting yields in optimal growth conditions, providing a cisgenic solution that reduces regulatory burdens.
Implementation Method 1
a fusion protein with a plastid targeting sequence, fused in frame with cytosolic 6-phosphogluconate dehydrogenase (6PGDH), wherein this fusion protein is able to import into a plastid of a plant cell
Data Source
AI summary
The disclosure relates to modification of a heat resistant cytoplasmic heat stable 6-phosphogluconate dehydrogenase (6PGDH) enzyme by fusing the cytoplasmic 6PGDH enzyme in frame to a plastid-targeting sequence. This modification allows the import of the cytoplasmic 6PGDH enzyme into plastids of a plant cell. Polynucleotides encoding and expressing the modified cytoplasmic 6PGDH enzymes are provided. The disclosure further provides transgenic plants and seeds containing the disclosed polynucleotides and expressing the modified cytoplasmic 6PGDH enzymes during development. The invention further relates to methods for developing a transgenic plant that has increased heat resistance and yield during heat stress.