Jose C. Huguet-Tapia, PhD
Research Scientist
University of Florida
Gainesville, FL, USA
Mukesh Jain, PhD
Research Coordinator
Department of Plant Pathology
Gainesville, Florida, United States
Amit Mondal
University of Florida
Gainesville, Florida, United States
Alison E. robertson, Dr
Professor
Iowa State University
Ames, Iowa, United States
Sanzhen Liu
Kansas State University
Manhattan, Kansas, United States
Yousong Ding
University of Florida
Gainesville, Florida, United States
Frank F. White, PhD
Professor
University of Florida
Gainesville, FL, USA
Clavibacter nebraskensis, the causative agent of Goss's wilt in maize, is a re-emerging pathogen with limited genetic characterization. Comparative genomics of C. nebraskensis isolates with varying pathogenicity revealed that independent missense mutations in a small, previously uncharacterized gene resulted in loss of virulence. This gene, named cvf1 (Clavibacter virulence factor 1), encodes a 107-amino acid protein conserved across actinobacteria, including all plant-pathogenic Clavibacter species. Complementation of cvf1 from the pathogenic strain Cn06-1 restored virulence in two nonpathogenic isolates, while deletion of cvf1 in Cn06-1 abolished pathogenicity. Transcriptomic analysis suggests that Cvf1 regulates a biosynthetic operon for the toxin aureonucleomycin (cn-anm) and two non-heme catalase genes. Deletion of cn-anm also resulted in a loss of pathogenicity, identifying an ANM-related toxin as a key virulence factor in C. nebraskensis and possibly other plant-pathogenic bacteria. These findings provide insights into the molecular basis of virulence in C. nebraskensis and its evolutionary adaptation within actinobacteria.