A fungal cytochrome P450 is expressed during the interaction between the fungal pathogen Heterobasidion annosum sensu lato and conifer trees

Abstract

The infection-related expression of a Heterobasidion annosum (Fr.) Bref. sensu lato (s.l.) putative cytochrome P450 gene (CPM2) was analysed with realtime quantitative PCR. CPM2 was highly expressed after 20 days of growth in bark of living spruce trees, and up-regulated by nitrogen starvation on artificial media. Infection of pine seedlings in the presence of high-carbon medium results in low expression levels of CPM2, thus indicating that starvation is the primary regulatory factor for induction of this gene. The predicted cpm2 protein contains 507 amino acids with an estimated molecular mass of 56.1 kDa, and display all conserved amino acids of the cytochrome P450 protein family. The protein has a high similarity to the ord1/ordA O-methylsterigmatocystin oxidoreductases from Aspergillus flavus/A. parasiticus, responsible for catalysing the final step in aflatoxin biosynthesis. Results indicate that cpm2 is potentially important for pathogenicity in H. annosum s.l.

• Heterobasidion annosum
• conifer root rot
• forest pathology
• gene expression
• cytochrome P450

Acknowledgements

This work was financed by the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning. We are grateful to Mårten Lind and Maria Jonsson for assistance with nucleic acid extractions and to Gunilla Swedjemark for spruce inoculations.

Notes

Nucleotide sequence data are deposited in GenBank with Accession No. AY827553.