Chimeric PG-PGIP Fusion Protein for Plant Immunity

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Solution Overview

Problem

Current methods lack direct evidence of oligogalacturonides (OGs) accumulation and their defensive function in plants, and transgenic plants expressing fungal polygalacturonase and polygalacturonase inhibitor protein (PGIP) do not consistently produce OGs, limiting their effectiveness in inducing plant immunity.

Innovation Solution

Engineering Arabidopsis plants to express a chimeric protein fusion of fungal polygalacturonase (PG) and PGIP, under a pathogen-inducible promoter, to accumulate OGs and activate defense responses, using specific amino acid sequences and linkers to ensure equimolar expression and intermolecular interaction without intramolecular inhibition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transgenic plants express fungal polygalacturonase and polygalacturonase inhibitor protein separately, then the inhibitor can recognize and inhibit some fungal polygalacturonases, but the plants do not consistently produce oligogalacturonides (OGs) and the effectiveness in inducing plant immunity is limited

Engineering Contradiction:

Improveconsistency of OG productionVSAvoideffectiveness in inducing plant immunity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent combines the fungal polygalacturonase (PG) and plant polygalacturonase inhibitor protein (PGIP) into a single chimeric fusion protein. This merging ensures that both the enzyme capable of producing OGs and the inhibitor that regulates its activity are expressed together in equimolar amounts, enabling consistent OG accumulation and effective induction of plant immunity that neither component could achieve alone.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the expression parameters by using a pathogen-inducible promoter to control the expression of the chimeric protein. This ensures that OG production is activated only when needed (upon pathogen detection), improving both the consistency and effectiveness of the immune response while avoiding unnecessary OG production under normal conditions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a chimeric fusion protein of PG and PGIP is engineered to ensure equimolar expression, then intermolecular interaction is promoted, but the complexity of protein design and construction increases

Engineering Contradiction:

Improveequimolar expression and interactionVSAvoidprotein fusion construct design

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a linker sequence as an intermediary component between the PG and PGIP domains in the chimeric fusion protein. This linker facilitates proper folding, stability, and intermolecular interaction between the two functional domains while maintaining equimolar expression, thereby achieving reliable OG production without requiring overly complex protein design.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If OGs are accumulated in plant tissues to activate defense responses, then plant resistance to pathogens increases, but the mechanisms of OG perception and signaling in plants remain incompletely understood

Engineering Contradiction:

Improveplant resistance to pathogensVSAvoidunderstanding of OG signaling mechanisms

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent employs a pathogen-inducible promoter that activates chimeric protein expression in response to pathogen detection. This feedback mechanism ensures that OG production is tightly regulated and activated only when needed, enhancing plant resistance while allowing researchers to study the signaling mechanisms under controlled, physiologically relevant conditions.

Inventive Principle:

Principle #23Feedback

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 results in increased resistance to pathogenic microorganisms by inducing OG production, activating defense responses, and demonstrating a controlled release of OGs, which activates a wide range of defense mechanisms in plants.

Implementation Method 1

Oligogalacturonides (OGs), oligomers of α-1,4-galacturonic acid released by the plant cell wall following a partial hydrolysis of homogalacturonan (HG)

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

the interaction between polygalacturonase (PG) and the polygalacturonase inhibitor protein (PGIP), located in the cell wall, can favour the accumulation of OGs with eliciting activity

Methodology Applied

Scientific EffectEnzyme inhibition: Enzyme

Data Source

PatentUS10385347B2Fusion protein and transgenic plant expressing said protein

Publication Date: 2019.08.20 UNIVERSITA DEGLI STUDI DI ROMA LA SAPIENZA

AI summary

The present invention concerns a nucleic acid molecule capable of expressing, in at least one plant tissue, a chimeric protein comprising a polygalacturonase (PG) of fungal, bacterial or insect origin and a plant polygalacturonase inhibitor protein (PGIP) plant capable of inhibiting said PG. The present invention also relates to transgenic plants that express said chimeric protein.