Modulating Maize Seed Traits via Sorbitol Dehydrogenase Gene Expression

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Solution Overview

Problem

The role of sorbitol dehydrogenase in maize is unclear, and existing technologies have not effectively modulated seed size, number, and sugar content in plants, as sorbitol's functions and metabolic pathways in maize differ from those in other species like apple and peach.

Innovation Solution

Inhibiting or knocking out the expression of the sorbitol dehydrogenase (Sdh) gene or increasing its expression to modulate seed size, number, and sugar content in plants, using methods such as antisense technology, siRNA, or ribozymes to alter Sdh gene activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If existing technologies are used to modulate seed characteristics, then seed size, number, and sugar content can be adjusted, but the methods are not effective in maize because sorbitol's functions and metabolic pathways in maize differ from those in other species

Engineering Contradiction:

Improveeffectiveness of modulationVSAvoidspecies-specific metabolic pathway differences

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The invention changes the metabolic parameter by knocking out the Sdh gene to block sorbitol conversion to fructose, thereby altering carbon flow and increasing sugar accumulation in maize seeds. This parameter change adapts the modulation approach to maize's specific metabolic pathway where sorbitol is a major transport form rather than a minor metabolite as in other species.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If Sdh gene expression is inhibited or knocked out, then seed size decreases and seed number increases with altered sugar profiles, but the role of sorbitol dehydrogenase in maize remains unclear

Engineering Contradiction:

Improveseed number and sugar contentVSAvoidunclear enzymatic function

Core Design Contradiction:

Quantity of substanceVSLoss of information

Solution Approach 1:

The invention converts the uncertainty about Sdh function into a benefit by using the knockout approach to discover that inhibiting Sdh increases seed number and alters sugar content. The 'harm' of unknown function becomes valuable information revealing that Sdh inhibition redirects carbon flow to increase carbohydrate accumulation and modify seed development in maize.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Volume of moving object

If Sdh gene expression is increased, then seed size increases but seed number decreases, demonstrating opposite effects compared to gene inhibition

Engineering Contradiction:

Improveseed sizeVSAvoidseed number

Core Design Contradiction:

Volume of moving objectVSQuantity of substance

Solution Approach 1:

The invention demonstrates dynamic control of seed development by showing that increasing or decreasing Sdh expression produces opposite phenotypic effects. This dynamic approach allows flexible modulation where upregulation promotes seed size enlargement while downregulation or knockout increases seed number, providing adaptable control over seed characteristics based on desired outcomes.

Inventive Principle:

Principle #15Dynamics

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 allows for the regulation of seed size, number, and sugar content in plants, demonstrating significant changes in seed characteristics and sugar levels, such as increased kernel number and altered sugar profiles in maize.

Implementation Method 1

When sorbitol is transported to sink tissues of apple or related species, it is converted to fructose by sorbitol dehydrogenase (SDH)

Methodology Applied

Scientific EffectOxidation-reduction reaction: Redox Reactions

Implementation Method 2

G6P is first converted to sorbitol 6-phosphate by aldose 6-phosphate reductase (A6PR; EC 1.1.1.200, also called sorbitol-6-phosphate dehydrogenase, S6PDH)

Methodology Applied

Scientific EffectReduction reaction: Reduction

Implementation Method 3

followed by hydrolysis of sorbitol 6-phosphate to form sorbitol via sorbitol-6-phosphate phosphatase (SorPP; EC 3.1.3.50)

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS10813324B2Materials and methods for modulating seed size, seed number, and seed sugar content in plants

Publication Date: 2020.10.27 UNIV OF FLORIDA RESEARCH FOUNDATION INC

AI summary

The subject invention concerns materials and methods for modulating seed size in plants. In one embodiment, seed size is decreased relative to wild type seed by inhibiting or knocking out expression of a sorbitol dehydrogenase (Sdh) gene or the gene product thereof. In another embodiment, seed size is increased relative to wild type seed by increasing expression of an Sdh gene or the gene product thereof. The subject invention also concerns materials and methods for modulating seed number or sugar content in plants. In one embodiment, seed number or sugar content is increased relative to wild type seed by inhibiting or knocking out expression of a sorbitol dehydrogenase (Sdh) gene or the gene product thereof. In another embodiment, seed number or sugar content is decreased relative to wild type seed by increasing expression of an Sdh gene or the gene product thereof.