Corn GA20 Oxidase Alleles for Lodging Resistance

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Solution Overview

Problem

There is a challenge in achieving increased yield and resistance to lodging in corn crops through manipulation of the gibberellin (GA) pathway, which has been successful in other cereal crops like wheat and sorghum but remains elusive in corn.

Innovation Solution

A method involving targeted genome editing to introduce a mutant allele of the GA20 oxidase genes in corn, specifically by generating double-stranded breaks and inserting antisense RNA sequences complementary to specific nucleotides of the GA20 oxidase genes, thereby regulating GA levels and promoting desirable plant traits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If GA pathway manipulation is applied to corn crops, then yield and lodging resistance should be improved, but the method has not been successful in corn despite success in other cereal crops

Engineering Contradiction:

ImproveyieldVSAvoidsuccess rate of GA pathway manipulation

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the GA20ox gene sequence through targeted insertion of antisense RNA sequences, altering the genetic parameters of the GA pathway to achieve the desired semi-dwarf phenotype and improved lodging resistance in corn that was not achievable with conventional approaches

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses antisense RNA sequences as intermediaries to mediate the suppression of GA20ox gene expression. These RNA molecules serve as the intermediary mechanism between the introduced DNA and the functional suppression of the target gene, enabling precise control of GA levels in corn

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If GA levels are reduced to achieve semi-dwarf phenotype, then lodging resistance is improved, but plant height may be excessively reduced

Engineering Contradiction:

Improvelodging resistanceVSAvoidplant height

Core Design Contradiction:

Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The patent applies partial action by inserting antisense RNA sequences that partially suppress GA20ox expression rather than completely eliminating it. This partial suppression achieves sufficient lodging resistance while maintaining plant heights that are agronomically acceptable, avoiding the excessive shortening that would occur with complete gene knockout

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the expression level parameter of GA20ox through controlled antisense RNA insertion, achieving an optimal balance between lodging resistance and plant height by fine-tuning the degree of gene suppression rather than applying extreme reductions

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12024711B2Methods and compositions for generating dominant short stature alleles using genome editing

Publication Date: 2024.07.02 MONSANTO TECHNOLOGY LLC

AI summary

The present disclosure provides compositions and methods for altering gibberellin (GA) content in corn or other cereal plants. Methods and compositions are also provided for altering the expression of genes related to gibberellin biosynthesis through editing of specific subtypes of GA20 oxidase genes to introduce an antisense sequence or segment into the gene. Modified plant cells and plants having a dominant allele reducing the expression or activity of one or more GA oxidase genes are further provided comprising reduced gibberellin levels and improved characteristics, such as reduced plant height and increased lodging resistance, but without off-types.