2024/08/15 by Daowen Huo, Nathaniel Westrick, Nathaniel M. Westrick +4
Agricultural and Biological Sciences · Environmental Science · Biochemistry, Genetics and Molecular Biology · #Plant pathogens and resistance mechanisms #Turfgrass Adaptation and Management #Plant Pathogens and Fungal Diseases
paper · pdf · doi:10.1094/phyto-03-24-0094-r
Dollar spot is a destructive foliar disease of amenity turfgrass caused by Clarireedia spp. fungi, mainly C. jacksonii, on the Northern United States region's cool-season grass. Oxalic acid (OA) is an important pathogenicity factor in related fungal plant pathogens such as Sclerotinia sclerotiorum; however, the role of OA in the pathogenic development of C. jacksonii remains unclear due to its recalcitrance to genetic manipulation. To overcome these challenges, a CRISPR/Cas9-mediated homologous recombination approach was developed. Using this novel approach, the oxaloacetate acetylhydrolase ( oah) gene that is required for the biosynthesis of OA was deleted from a C. jacksonii wild-type (WT) strain. Two independent knockout mutants, Δ Cjoah-1 and Δ Cjoah-2, were generated and inoculated on potted creeping bentgrass along with a WT isolate and a genome sequenced isolate LWC-10. After 12 days, bentgrass inoculated with the mutants Δ Cjoah-1 and Δ Cjoah-2 exhibited 59.41% lower dollar spot severity compared with the WT and LWC-10 isolates. OA production and environmental acidification were significantly reduced in both mutants when compared with the WT and LWC-10. Surprisingly, stromal formation was also severely undermined in the mutants in vitro, suggesting a critical developmental role of OA independent of plant infection. These results demonstrate that OA plays a significant role in C. jacksonii virulence and provide novel directions for future management of dollar spot. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .