CRISPR/Cas9-Enabled Promoter Editing to Improve Rice Yield and Disease Resistance
Open Access
- Author:
- Hsieh-Feng, Vicki
- Graduate Program:
- Plant Biology (MS)
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- October 20, 2021
- Committee Members:
- Yinong Yang, Thesis Advisor/Co-Advisor
Claude Walker Depamphilis, Committee Member
Teh-Hui Kao, Program Head/Chair
Majid R Foolad, Committee Member - Keywords:
- CRISPR/Cas9
promoter editing
Oryza sativa
rice breeding
grain yield
disease resistance
IPA1
Bsr-d1
CRISPR/Cas9
promoter editing
Oryza sativa
rice breeding
grain yield
disease resistance
IPA1
Bsr-d1 - Abstract:
- High yield and disease resistance are two of the most important breeding goals for food security as the world experiences rapid population growth and climate change. With the powerful and versatile Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated system (CRISPR/Cas) technology, crop genomes can be precisely manipulated to improve agronomically important traits and accelerate the development of elite crop cultivars. This study aims to demonstrate CRISPR/Cas technology for broader applications in crop breeding through promoter editing. CRISPR/Cas9-enabled multiplex genome editing was carried out to mutagenize the promoter region of two rice genes associated with yield and/or disease resistance, generating diverse set of regulatory elements and a pool of dosage effect alleles beneficial for crop phenotypic selection and trait improvement. To facilitate multiplex editing in rice promoters, the polycistronic tRNA-gRNA (PTG) multiplex editing strategy was employed to efficiently generate novel promoter alleles for IPA1 (Ideal Plant Architecture 1) and Bsr-d1 (Broad-Spectrum Resistance-Digu 1) genes in commercial rice cultivar ‘Jupiter’ that is widely grown in the southern US. By targeting the IPA1 and Bsr-d1 promoters with eight specific guide RNAs (gRNAs), respectively, a diverse array of insertions and deletions were generated and verified in both promoters. Selected mutant lines were characterized in the subsequent generations to obtain transgene-free, homozygous plants for further evaluation of yield and disease resistance phenotypes. Yield improvement and enhanced disease resistance of these promoter-edited rice lines are expected to be evaluated in field trials for potential commercialization and variety release in the future.