Analysis of manganese-regulated gene expression in the ligninolytic basidiomycete Ceriporiopsis subvermispora

Abstract

In this work, we explore the use of the unbiased cDNA-AFLP strategy to identify genes involved in Mn2+ homeostasis in Ceriporiopsis subvermispora. In this ligninolytic white-rot fungus, whose genome has not yet been sequenced, three Mn peroxidase genes responding to Mn2+ have been characterized. Using cDNA-AFLP to identify transcript-derived fragments (TDFs), a total of 37 differentially expressed cDNA fragments were identified by comparing band intensities among cDNA-AFLP patterns obtained from mycelia from cultures supplemented with different concentrations of Mn2+. Of 21 differentially expressed TDFs, nine were classified as upregulated, five as downregulated and seven as unregulated. Of these, six upregulated and two downregulated TDFs were selected for further characterization. The expected TDFs for the known Mn peroxidases were not isolated, but several genes encoding proteins related to protein sorting, storage and excretion of excess Mn2+ were identified. Transcripts induced under Mn2+ supplementation exhibited homologies to the elongation factor eEF3, a HDEL sequence binding protein and the ARD1 subunit of the N-acetyltransferase complex, among others. Overall, the results obtained in this study suggest a complex picture of Mn2+ homeostasis and provide the possibility to search for common regulatory elements in the promoters of the novel putatively identified genes.