Background: Resistance to carbendazim and other benzimidazole fungicides in Botrytis cinerea (Pers. ex Fr.) and most other fungi is usually conferred by mutation(s) in a single chromosomal beta-tubulin gene, often with several allelic mutations. In Fusarium graminearum Schwade, however, carbendazim resistance is not associated with a mutation in the corresponding beta-tubulin gene.
Results: The beta-tubulin gene conferring carbendazim resistance in B. cinerea was cloned and connected with two homologous arms of the beta-tubulin gene of F. graminearum by using a double-joint polymerase chain reaction (PCR). This fragment was transferred into F. graminearum via homologous double crossover at the site where the beta-tubulin gene of F. graminearum is normally located (the beta-tubulin gene of F. graminearum had been deleted). The transformants were confirmed and tested for their sensitivity to carbendazim.
Conclusion: The beta-tubulin gene conferring carbendazim resistance in B. cinerea could not express this resistance in F. graminearum, as transformants were still very sensitive to carbendazim.