Zinc finger transcription factor FoZfp1 is required for growth, conidiation, osmoregulation, and full virulence in the Polygonatum kingianum pathogen Fusarium oxysporum

Abstract Polygonatum kingianum rhizome rot is a destructive soil-borne disease caused by Fusarium oxysporum, which adversely affects the yield and sustainable development of P. kingianum. However, there are few effective control measures against rhizome rot. Thus, understanding the infection mechanism of F. oxysporum is essential to manage rhizome rot in P. kingianum effectively. In this study, zinc finger transcription factor FoZfp1 consisting of two C2H2 motifs was up-regulated during F. oxysporum conidial germination. The FoZfp1 gene deletion mutant (△FoZfp1) and the mutant complementary (△FoZfp1-C) strains were generated by the target gene replacement technique. Biological characteristic analyses revealed that the △FoZfp1 mycelial growth and conidial production were slower than those of the wild-type F. oxysporum (WT) and △FoZfp1-C. Additionally, the inhibition rates and sensitivity of △FoZfp1 under cell wall and osmotic targeted stresses were decreased compared to those of WT and △FoZfp1-C. Pathogenicity assays further revealed that the virulence of △FoZfp1 on the P. kingianum leaves and rhizomes was significantly reduced. These results indicate that FoZfp1 is associated with mycelial growth, conidiation, osmoregulation, and pathogenicity in F. oxysporum on P. kingianum.