Genomewide investigation into DNA elements and ABC transporters involved in imazalil resistance in Penicillium digitatum

Penicillium digitatum, causing citrus green mold, is one of the most devastating pathogenic fungi for postharvest fruits. The disease control is becoming less efficient because of the dispersal of fungicide-resistant strains. However, genome-scale analyses of its resistance mechanism are scarce. In this work, we sequenced the whole genome of the R1 genotype strain Pd01-ZJU and investigated the genes and DNA elements highly associated with drug resistance. Variation in DNA elements related to drug resistance between P.digitatum strains was revealed in both copy number and chromosomal location, indicating that their recent and frequent translocation might have contributed to environmental adaptation. In addition, ABC transporter proteins in Pd01-ZJU were characterized, and the roles of typical subfamilies (ABCG, ABCC, and ABCB) in imazalil resistance were explored using real-time PCR. Seven ABC proteins, including the previously characterized PMR1 and PMR5, were induced by imazalil, which suggests a role in drug resistance. In summary, this work presents genome information of the R1 genotype P.digitatum and systematically investigates DNA elements and ABC proteins associated with imazalil resistance for the first time, which would be indicative for studying resistant mechanisms in other pathogenic fungi.