Characterization of three mnp genes of Fomitiporia mediterranea and report of additional class II peroxidases in the order hymenochaetales.

We report the sequence-based characterization and expression patterns of three manganese peroxidase genes from the white rot fungus and grape vine pathogen Fomitiporia mediterranea (Agaricomycotina, Hymenochaetales), termed Fmmnp1, Fmmnp2, and Fmmnp3. The predicted open reading frames (ORFs) are 1,516-, 1,351-, and 1,345-bp long and are interrupted by seven, four, and four introns, respectively. The deduced amino acid sequences encode manganese peroxidases (EC 1.11.1.13) containing 371, 369, and 371 residues, respectively, and are similar to the manganese peroxidases of the model white rot organism Phanerochaete chrysosporium. The expression of the genes is most likely differentially regulated, as revealed by real-time PCR analysis. Phylogenetic analysis reveals that other members of the order Hymenochaetales harbor mnp genes encoding proteins that are related only distantly to those of F. mediterranea. Furthermore, multiple partial lip- and mnp-like sequences obtained for Pycnoporus cinnabarinus (Agaricomycotina, Polyporales) suggest that lignin degradation by white rot taxa relies heavily on ligninolytic peroxidases and is not efficiently achieved by laccases only.