Plant Drought and Heat Tolerance via PEPC Mutation and HSP Expression
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Solution Overview
Problem
Current crops utilizing C3 or C4 photosynthesis are vulnerable to drought and heat stress, which will be exacerbated by global warming, necessitating improved drought and heat tolerance for sustainable food and biomass production.
Innovation Solution
Introduction of exogenous nucleic acids encoding heat shock proteins (HSP) such as HSP40, HSP60, and HSP70, and phosphoenolpyruvate carboxylase (PEPC) with an aspartic acid mutation at position 509, expressed in plants using CRISPR/Cas system or other genome editing methods to enhance drought and heat tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If C3 or C4 photosynthesis pathways are used in crops, then food and biomass production is achieved, but drought and heat tolerance is poor
Solution Approach 1:
The patent introduces specific amino acid mutations in PEPC (position 509) and PPDK (position 486) enzymes to alter their kinetic parameters and thermal stability, enabling C3 plants to perform CAM-like nocturnal carbon fixation while maintaining improved drought and heat tolerance under daytime conditions
Solution Approach 2:
The patent divides the carbon fixation process into two distinct phases: nocturnal CO2 uptake and fixation by PEPC, and daytime Calvin cycle by RuBisCO, separating the water-loss-prone stomatal opening from the photosynthetic activity to reduce transpirational water loss while maintaining productivity
2Temperature
If global warming continues, then temperature increases, but crop vulnerability to heat stress worsens
Solution Approach 1:
The patent introduces heat shock protein genes (HSP70, HSP90, HSP100) that are constitutively expressed or inducibly activated before severe heat stress occurs, preparing the plant's molecular chaperone system to protect proteins from denaturation and maintain cellular function under elevated temperatures
Solution Approach 2:
The patent exploits the heat stress response pathway by introducing engineered heat shock promoters that activate protective gene expression under heat conditions, converting the harmful thermal stress into a trigger for enhanced heat tolerance mechanisms
3Quantity of substance
If drought conditions occur, then water availability decreases, but plant growth and biomass production are reduced
Solution Approach 1:
The patent implements dynamic regulation of stomatal conductance through ABA signaling pathway modifications, allowing stomata to remain closed during daytime to conserve water while opening at night for CO2 uptake, dynamically adapting gas exchange to environmental conditions to maintain productivity under drought
Solution Approach 2:
The patent introduces malic acid as an intermediary carbon storage molecule that accumulates during nocturnal CO2 fixation and is decarboxylated during daytime to provide CO2 for RuBisCO, mediating between water conservation requirements and photosynthetic carbon fixation needs
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 genetic modification significantly improves drought and heat tolerance in plants, enabling them to sustain normal growth and biomass production under water-scarce conditions, thus addressing the challenges posed by global warming.
Implementation Method 1
introducing into the plant an exogenous nucleic acid encoding at least one heat shock protein (HSP) selected from the group consisting of HSP40, HSP60 and HSP70
Implementation Method 2
Nocturnal uptake of atmospheric CO2 via open stomata and fixation of carbon (C) by phosphoenolpyruvate-carboxylase (PEPC), leading to the formation of malic acid
Implementation Method 3
Daytime C3 photosynthesis mediated by ribulose-1,5-bis-phosphate carboxylase/oxygenase (RuBisCO) that re-fixes CO2 generated from decarboxylation of malic acid when stomatal conductance is at a minimum
Implementation Method 4
enhances plant water-use efficiency (WUE) and drought tolerance by reducing transpirational water loss through daytime stomatal closure
Data Source
AI summary
The present disclosure provides methods for increasing drought resistance and heat resistance of a plant. The methods encompass expression of at least one heat shock protein (HSP) from the group consisting of HSP40, HSP60 or HSP70 together with a phosphoenolpyruvate carboxylase (PEPC) comprising an aspartic acid (D) at a position that corresponds to the position 509 of SEQ ID NO: 4, in the plant. In comparison to a plant not manipulated in this manner, the disclosed, genetically-modified, plants display improved drought resistance and heat resistance. Also provided are plants that can be obtained by the method according to the invention, and nucleic acid vectors to be used in the described methods.