A novel ABC transporter gene ABC2 involved in multidrug susceptibility but not pathogenicity in rice blast fungus, Magnaporthe grisea

We cloned a novel ATP-binding cassette (ABC) transporter gene ABC2 from the rice blast fungus, Magnaporthe grisea. ABC2 protein had nucleotide-binding folds (NBF) and predicted transmembrane domains (TMD6) arranged in a duplicate [NBF-TMD6]2 configuration and showed the highest amino acid homology with BMR1 of Botrytis cinerea. Transcription of the gene was up-regulated by treatment with many toxicants, including several blasticides, demethylation inhibitors (DMI), and antibiotics. ABC2 disruptants displayed an increased sensitivity to bitertanol, myclobutanil, and tebuconazole (DMIs), camptothecin (alkaloid) and cycloheximide (antibiotic). This result demonstrated that ABC2 is a member of multidrug transporters. We performed infection assay of ABC2 disruptants towards rice. However, no obvious difference of disease severities between ABC2 disruptants and wild-type strain was observed, demonstrating that ABC2 is not involved in pathogenicity.