CRN Gene Editing for Controlled Meristem Size in Corn
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Solution Overview
Problem
Existing strategies for modulating meristem size in plants, such as through CLV-WUS signaling, often result in uncontrollable meristem expansion and disordered organ growth, limiting yield improvements in crops like maize.
Innovation Solution
Introduce non-natural mutations in the CORYNE (CRN) gene using CRISPR-Cas editing systems to target specific regions with high sequence identity, leading to controlled meristem size regulation and increased kernel row number in corn plants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If loss-of-function mutations in CLV-WUS signaling genes are introduced to increase meristem size, then kernel row number increases, but meristem organization becomes disordered and yield does not improve
Solution Approach 1:
The patent introduces specific point mutations (amino acid substitutions) in the CRN protein's extracellular domain rather than complete loss-of-function mutations. This changes the parameter of CRN activity partially, allowing increased meristem size and kernel row number while preserving enough organizational control to avoid fasciation and maintain yield improvement
Solution Approach 2:
Instead of complete loss-of-function mutations that cause excessive meristem expansion and disorganization, the patent applies partial action through specific amino acid substitutions that moderately increase meristem size. This partial modification achieves increased kernel row number without the harmful effects of complete pathway disruption
2Volume of moving object
If strong loss-of-function mutations in CRN gene are introduced, then meristem size increases, but ear disorganization occurs and yield increase is prevented
Solution Approach 1:
The patent changes the parameter of CRN function by introducing specific amino acid substitutions in the extracellular domain rather than complete loss-of-function mutations. This partial modification allows meristem expansion while maintaining sufficient organizational control to ensure reliable yield improvement
Solution Approach 2:
The patent creates a modified version of the CRN protein with specific amino acid substitutions that copies the essential functions of wild-type CRN while altering the extracellular domain to reduce over-repression of WUS expression, achieving balanced meristem control
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 CRISPR-Cas editing of the CRN gene results in transgene-free corn plants with enhanced kernel number and yield, along with improved disease resistance and maintained meristem organization.
Implementation Method 1
a guide nucleic acid (gRNA, gDNA, crRNA, crDNA, sgRNA, sgDNA) comprising a spacer sequence with complementarity to an endogenous target gene encoding an CRN protein
Implementation Method 2
A third aspect of the invention provides a corn plant cell comprising at least one non-naturally occurring mutation within a CRN gene, wherein the mutation is a substitution, insertion or a deletion that is introduced using an editing system that comprises a nucleic acid binding domain that binds to a target site in the CRN gene
Data Source
AI summary
This invention relates to compositions and methods for modifying CORYNE (CRN) genes in plants to optionally increase kernel row number and/or improve one or more yield traits. The invention further relates to plants having increased kernel row number and/or one or more improved yield traits produced using the methods and compositions of the invention.