2019
Non-Transgenic Generation of Herbicide Resistance in Soybean Using CRISPR Base Editing
Category:
Sustainable Production
Keywords:
AgricultureCrop protectionHerbicide
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Feng Qu, Ohio Agricultural Research and Development Center
Co-Principal Investigators:
Project Code:
NCSRP
Contributing Organization (Checkoff):
Leveraged Funding (Non-Checkoff):
None.
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Institution Funded:
Brief Project Summary:

This project strives to address the concern that weeds are becoming an increasingly serious threat to soybean production as existing and emerging weeds become tolerant to the limited selection of herbicides used in soybean fields. This project addresses the problem by equipping soybeans with new genetic traits that confer tolerance to three novel classes of herbicides, allowing these herbicides to be used on soybean. Specifically, the project will address two inter-connected goals: establish a CRISPR base editing system that generates non-transgenic herbicide-resistant soybean quickly; and then use the new system to produce novel herbicide resistance traits, ideally double or triple herbicide resistance.

Key Benefactors:
farmers, agronomists, scientists, breeders

Information And Results
Project Deliverables

Should the project progress as planned, we expect to garner the following deliverables that will directly benefit soybean growers by increasing the profit of growing soybean while reducing inputs:
• A fast, cost-effective, and non-transgenic base editing protocol for accurately modifying soybean genes without disrupting their functions;
• Multiple soybean lines resistant to diverse herbicides generated with the new base editing technology;
• Multiple soybean cultivars equipped with the base editing BE3 enzyme, as well as other base-editing Cas9 with more advanced characteristics, ready to be utilized by the soybean research community for editing other soybean gene in order to improve soybean seed quality and yield.

Final Project Results

Updated October 1, 2019:
First of all, we wish to thank NCSRP for the decision to continued support!
By now we have completed the first year of this NCSRP-funded project. We are proud to announce that we have met the milestones – with the generated soybean plants being reared for seed production.
• Specifically, we have successfully assembled a construct that contains both the BE3 base-editing Cas9 enzyme, and a guide RNA designed to guide BE3 to a specific position in the soybean ALS gene to mediate the editing of specific bases, leading to herbicide (Imazapyr) resistance. This plasmid is named as pWI-BE3-gGmALS. We also produced another construct that would express the BE3 enzyme only, designated as pWI-BE3 (milestone 2).
• Both constructs have been used to transform embryogenic tissues generated from young soybean seed, using a particle bombardment procedure. We obtained five (5) transgenic events for pWI-BE3-gGmALS, and one (1) event for pWI-BE3, from which transgenic seedlings are being induced. At least one event appears to contain the successfully base-edited ALS gene. Other events may also yield base-edited seedlings because the construct continues to carry out the editing while the tissues are being induced for seedling differentiation (milestone 1).
• Both the pWI-BE3-gGmALS and pWI-BE3 constructs have been sent to collaborators in Nebraska, Missouri, and Minnesota for producing base-edited plants in other soybean varieties (milestone 3). The transformed tissues are being selected for herbicide tolerance.

Finally, in preparation for the second year of the project, we have also been investigating the potential of adopting a new homologous recombination protocol, named as CRISPEY, in the research of generating novel herbicide tolerance traits. We are also testing a novel base-editing Cas9 that would allow us to modify a longer stretch of genes.
Again, we wish to thank NCSRP for the renewal of our project, and for the confidence you placed with us!

1. We have calibrated a streamlined protocol to quickly turn very young soybean seed into embryonic tissues in liquid cultures.
2. We have engineered the DNA constructs that once delivered into soybean cells, drive the so-called CRISPR base editing to modify specific soybean genes.
3. We used the two sets of tools outlined above to alter one of the soybean genes, known as GmALS1, at one of the amino acid positions.
4. We have succeeded in modifying the GmALS1 gene in a specific way that turned it into an enzyme that degrades the herbicide Imazapyr. This has been done in one soybean cultivar. The same set of DNA constructs are being tested in other soybean cultivars.
5. We are currently rearing the soybean seedlings in which GmALS1 has been modified in greenhouse, waiting for seed to set.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.