Functional Outlook of Penicillium digitatum PdMFS6 Transporter to Elucidate Its Role in Fungicide Resistance and Virulence

A novel <i>Penicillium digitatum</i> MFS transporter, PdMFS6 (PDIP_42530), was recognized, and its function was studied to explain its relevance in the simultaneous development of resistance to different fungicide spectrums. No changes were detected after application of chemical fungicides in mutants with the deleted gene, but chemical susceptibility was severely impaired in overexpressing strains, that became persistent to different chemicals. Furthermore, <i>P. digitatum</i> deleted transformants showed less fungal virulence appraise upon citrus infection stored at 20 °C. In strains derived from Pd149-<i>P. digitatum</i> with low virulence and overexpressing PdMFS6, the signs of the disease were more evident. In addition, evaluation of gene transcription showed an increase in PdMFS6 gene expression over time in all <i>P. digitatum</i> strains tested. It is noteworthy that during citrus fruit infection, the wild-type Pd1 strain displayed an augmented level of transcription, indicating that this transporter plays a role in infectivity. The fungal transporter PdMFS6 could contribute to the susceptibility to chemicals commonly used in postharvest treatments, as well as to rise the virulence of <i>P. digitatum</i> during fruit infection.