The postharvest pathogen Penicillium digitatum is responsible for green mold decay on citrus fruit causing important economic losses. To examine possible elements involved in fungal pathogenesis/virulence and fungicide resistance, identification and functional characterization of PdSte12, a particular type of C2H2 fungal transcription factor was carried out. PdSte12 was functionally inactivated through homologous recombination. The deletant fungal strains (Delta PdSte12) failed to cause green mold decay on citrus fruit. Delta PdSte12 mutants exhibited reduced growth and impaired conidiogenesis during fungal infection towards citrus fruit. Additionally, PdSte12 was characterized via overexpression transformants, showing higher infectivity rate in a low virulence P. digitatum strain, providing evidence of PdSte12's role in virulence. Moreover, fungicide sensitivity evaluation showed that PdStel2 was not involved in fungicide resistance as other transcription factors are. These results indicate that the PdStel2 transcription factor controls invasive growth and asexual reproduction as the major virulence function. (C) 2016 Elsevier B.V. All rights reserved.