CRISPR-Editing AsDREBL Improved Creeping Bentgrass Abiotic Stress Tolerance

Cool-season creeping bentgrass (Agrostis stolonifera L., As) is extensively used on golf courses worldwide and is negatively affected by several fungal diseases and abiotic stresses including drought and salinity. CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated) gene editing technology was employed in this project to knock out the AsDREBL (dehydration responsive element binding-like factor) gene, a potential negative regulator in stress tolerance. With our established single guide RNA (sgRNA)-based CRISPR-editing vector and optimized creeping bentgrass tissue culture system using mature seed-derived embryogenic calli of cv. Crenshaw as explant, more than 20 transgenic plants were produced by gene gun bombardment. Fifteen confirmed AsDREBL mutant plants were tested for drought and salinity tolerance by withholding water and applying salt spray in greenhouse settings. Some of the mutants were shown to be more tolerant of drought and salinity stress compared to the non-edited, wild type Crenshaw plants. Our results demonstrate that CRISPR-gene editing technology can be successfully applied to improve the agronomical traits of turfgrass.