Stomatal Density Control via OST1 Kinase for Drought Tolerance

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Solution Overview

Problem

Current methods for manipulating water and carbon dioxide exchange through plant stomata are limited in enhancing water use efficiency and drought tolerance, particularly under conditions of elevated atmospheric carbon dioxide.

Innovation Solution

Modulating the expression of a novel apoplastic subtilisin-like serine endopeptidase-like protein and controlling stomatal movement through the regulation of CO2 sensor genes and OST1 protein kinase, along with related kinases, to optimize stomatal density and function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If stomatal density is increased to enhance CO2 uptake, then photosynthetic carbon fixation is improved, but water loss through transpiration increases

Engineering Contradiction:

Improvephotosynthetic carbon fixationVSAvoidwater loss

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The invention changes the molecular parameters of guard cells by introducing heterologous proteins (OST1 kinase, SnRK2.2, SnRK2.3) that alter stomatal response characteristics. These parameter changes enable stomata to maintain higher density while responding more efficiently to CO2 levels, thereby improving carbon fixation without proportionally increasing water loss.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The introduced kinase proteins enhance the feedback mechanism in guard cells, making stomatal opening and closing more responsive to internal and external signals. This improved feedback allows for tighter control of stomatal aperture, enabling the plant to optimize CO2 uptake while minimizing unnecessary water loss through transpiration.

Inventive Principle:

Principle #23Feedback

2Loss of substance

If stomatal density is decreased to reduce water loss, then water use efficiency is improved, but CO2 uptake is reduced

Engineering Contradiction:

Improvewater lossVSAvoidCO2 uptake

Core Design Contradiction:

Loss of substanceVSProductivity

Solution Approach 1:

By modifying the molecular parameters of existing guard cells through heterologous protein expression, the invention enables each stomate to be more efficient. This allows for reduced stomatal density while maintaining or improving CO2 uptake capacity, as each remaining stomate functions more effectively in regulating gas exchange.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The introduced kinase proteins enable guard cells to better self-regulate their turgor status and stomatal aperture in response to environmental conditions. This enhanced self-service capability allows the plant to maintain optimal CO2 uptake with fewer stomata, improving water use efficiency without sacrificing productivity.

Inventive Principle:

Principle #25Self-service

3Reliability

If stomatal response to CO2 is enhanced to improve water use efficiency, then drought tolerance is improved, but stomatal development control becomes more complex

Engineering Contradiction:

Improvedrought toleranceVSAvoidstomatal development control

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention introduces intermediary kinase proteins (OST1, SnRK2.2, SnRK2.3) that act as mediators between CO2 sensing mechanisms and stomatal response execution. These intermediary proteins simplify the overall control architecture by providing dedicated molecular components that handle the complex signaling and regulatory functions, making the system more manageable and reliable.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This approach increases water use efficiency, biomass production, and drought tolerance in plants by regulating stomatal activity and density, effectively balancing water loss and CO2 uptake.

Implementation Method 1

increasing the expression and/or activity of a serine endopeptidase...capable of cleaving or cleaves an EPF2 protein

Methodology Applied

Scientific EffectProteolytic cleavage: Hydrolysis

Implementation Method 2

Each stomate is made up of a specialized pair of cells named guard cells, which can modify the size of the stomatal pore by controlling guard cell turgor status

Methodology Applied

Scientific EffectTurgor pressure regulation: Osmotic Pressure

Implementation Method 3

The concentration of CO2 regulates stomatal density, where high levels of CO2 will lead to a decrease in stomatal density

Methodology Applied

Scientific EffectCO2 sensing:

Implementation Method 4

water is lost through the process of transpiration through the stomatal pores

Methodology Applied

Scientific EffectTranspiration: Transpiration

Implementation Method 5

Carbon dioxide is taken up for photosynthetic carbon fixation

Methodology Applied

Scientific EffectPhotosynthesis: Photosynthesis

Data Source

PatentUS10689660B2Compositions and methods for mediating plant stomatal development in response to carbon dioxide and applications for engineering drought tolerance in plants

Publication Date: 2020.06.23 RGT UNIV OF CALIFORNIA

AI summary

In alternative embodiments, the invention provides compositions and methods for manipulating the exchange of water and/or carbon dioxide (CO2) through plant stomata by controlling the expression of a novel apoplastic subtilisin-like serine endopeptidase-like protein. In alternative embodiments, the invention provides plants having increased water use efficiency, and drought-resistant plants; and methods for engineering of water transpiration and water use efficiency in plants, and engineering plants with increased water use efficiency and drought-resistant plants.