Transgenic Plant Nitrite Reductase Gene Expression
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Solution Overview
Problem
Current methods for reducing nitrite content in plants are inadequate, leading to adverse effects such as nitrosamine formation and health risks, as well as environmental concerns due to excessive nitrate accumulation, which existing genetic modification techniques have not fully addressed.
Innovation Solution
Introducing an exogenous gene encoding a nitrite reductase into plants to reduce nitrite content through genetic engineering, using a chimeric gene with a promoter sequence that directs expression of the nitrite reductase, thereby enhancing nitrogen assimilation and reducing toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nitrate is supplied in excess to enhance nitrogen assimilation and plant growth, then plant growth and chlorophyll content increase dramatically, but nitrite accumulates to deleterious levels causing chlorosis and health risks
Solution Approach 1:
The patent extracts and removes the harmful nitrite accumulation problem by introducing an exogenous nitrite reductase gene that specifically targets and reduces nitrite levels in the plant, separating the beneficial nitrogen assimilation function from the harmful nitrite accumulation effect
Solution Approach 2:
The patent introduces an intermediary substance - the exogenous nitrite reductase enzyme - that mediates between the high nitrate supply and the harmful nitrite accumulation, converting nitrite to ammonium and preventing nitrite buildup while maintaining nitrogen assimilation benefits
2Object-generated harmful factors
If existing genetic modification techniques are used to reduce nitrite content, then some nitrite reduction is achieved, but adverse effects such as nitrosamine formation and environmental concerns remain
Solution Approach 1:
The patent changes the key parameter of nitrite reductase activity by introducing an exogenous gene that increases enzyme activity beyond natural levels, enabling more effective nitrite conversion to ammonium and achieving greater nitrite reduction than existing techniques
Solution Approach 2:
The patent converts the harmful nitrite accumulation problem into a benefit by using the introduced nitrite reductase enzyme to systematically convert nitrite into beneficial ammonium, transforming the harmful substance into a useful nitrogen source for plant growth
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 approach effectively decreases nitrite levels in transgenic plants, mitigating the adverse effects of nitrite accumulation and enhancing nitrogen assimilation, thereby improving plant safety for human and animal consumption and reducing environmental impact.
Implementation Method 1
Nitrite is then rapidly reduced to ammonium by nitrite reductase (NiR) in the chloroplasts of leaves or in the plastids of non-photosynthetic organs
Implementation Method 2
Nitrite reductase (NiR) is the second enzyme in the nitrate assimilation pathway and involves the transfer of 6 electrons from reduced ferredoxin to nitrite to form ammonium
Implementation Method 3
NR is considered to be the rate-limiting factor for growth and nitrate assimilation and is the first committed step of nitrogen assimilation. It catalyses the 2 electron reduction of nitrate to nitrite
Implementation Method 4
NR catalyses the 2 electron reduction of nitrate to nitrite using NAD(P)H as an electron donor
Implementation Method 5
In the chloroplast the ammonium then enters the glutamine synthetase/glutamate synthase cycle (GS/GOGAT) where it is incorporated into the amino acid pool
Data Source
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AI summary
The present invention relates in one aspect to a method for producing a transgenic plant, comprising introducing into an unmodified plant an exogenous gene encoding a nitrite reductase, wherein expression ofthe nitrite reductase encoded by the exogenous gene reduces nitrite content in the transgenic plant relative to the unmodified plant. Also provided are transgenic plants and plant cells comprising an exogenous gene encoding a nitrite reductase, as well as associated uses, chimaeric genes and plant transformation vectors.