OsNRT2.3b Nitrate Transporter Overexpression for Crop Yield
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Solution Overview
Problem
Current crop production relies heavily on chemical fertilizers, with nitrogen (N) use efficiency being only 30-50%, leading to environmental degradation and economic losses, and there is a need for more nutrient-efficient crop genotypes to ensure sustainable food security and reduce environmental impacts.
Innovation Solution
Overexpression of the rice nitrate transporter OsNRT2.3b, which has a pH-sensitive regulatory site, is used in transgenic plants to improve nitrogen use efficiency and growth by enhancing both nitrate and ammonium uptake, and regulating pH homeostasis, demonstrating improved growth, yield, and nitrogen use in rice and other species.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical fertilizers are used to increase crop productivity, then grain yield is improved, but nitrogen use efficiency deteriorates (only 30-50% efficiency)
Solution Approach 1:
The patent modifies the expression level and activity of nitrate transporter proteins (NRT1 and NRT2 families) in plant roots through genetic engineering. By overexpressing specific nitrate transporter genes, the patent increases nitrate uptake capacity and efficiency, allowing plants to acquire nitrogen more effectively from the soil, thereby improving nitrogen use efficiency while maintaining or increasing grain yield.
2Productivity
If chemical fertilizers are applied to achieve maximum yield, then crop production is improved, but environmental degradation occurs
Solution Approach 1:
The patent alters the nitrate uptake parameters by engineering enhanced expression of nitrate transporter genes. This enables plants to achieve maximum yield with reduced fertilizer input, as the improved transporter efficiency allows for better nitrogen acquisition from available soil nutrients, thereby reducing the need for excessive chemical fertilizer application and associated environmental harm.
3Quantity of substance
If nitrate uptake systems are increased to improve nitrogen acquisition, then nitrogen use efficiency is improved, but plant complexity increases
Solution Approach 1:
The patent utilizes existing nitrate transporter protein families (NRT1 and NRT2) that serve multiple functions in nitrate acquisition across different soil conditions. By overexpressing specific members of these families, the patent enhances nitrogen uptake capacity without introducing entirely new complex systems, leveraging the universal functionality of these transporter proteins to improve nitrogen acquisition efficiently.
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
Transgenic plants overexpressing OsNRT2b show increased grain yield, improved nitrogen use efficiency, and better pH regulation, leading to enhanced growth and nitrogen acquisition, even in plants that typically use different nitrogen sources, thus addressing the inefficiencies of traditional fertilizer use.
Implementation Method 1
Both electrophysiological and molecular studies have shown that nitrate uptake through both HATS and LATS is an active process mediated by proton/nitrate co-transporters
Implementation Method 2
Only OsNRT2.3b had a pH-sensitive regulatory site on the cytoplasmic face of the protein. This pH sensing site was confirmed by site-directed mutagenesis of a histidine amino acid residue (H167R) in the pH sensing motif.
Implementation Method 3
The specialized aerenchyma cells in rice roots can transfer oxygen from the shoots to the roots and release it to the rhizosphere, where bacterial conversion of ammonium to nitrate (nitrification) can take place
Data Source
Figure 1a~1c
Figure 1d
Figure 1e
AI summary
The invention relates to transgenic plants with improved growth and nitrogen use efficiency expressing nitrate transporter gene,methods of making such plants and methods for improving growth and nitrogen use efficiency.