High mobility group (HMG-box) genes in the honeybee fungal pathogen Ascosphaera apis.

The genome of the honeybee fungal pathogen Ascosphaera apis (Maassen) encodes three putative high mobility group (HMG-box) transcription factors. The predicted proteins (MAT1-2, STE11 and HTF), each of which contain a single strongly conserved HMG-box, exhibit high similarity to mating type proteins and STE11-like transcription factors previously identified in other ascomycete fungi, some of them important plant and human pathogens. In this study we characterized the A. apis HMG-box containing genes and analyzed the structure of the mating type locus (MAT1-2) and its flanking regions. The MAT1-2 locus contains a single gene encoding a protein with an HMG-box. We also have determined the transcriptional patterns of all three HMG-box containing genes in both mating type idiomorphs and discuss a potential role of these transcription factors in A. apis development and reproduction. A multiplex PCR method with primers amplifying mat1-2-1 and Ste11 gene fragments is described. This new method allows for identification of a single mating type idiomorph and might become an essential tool for applied and basic research of chalkbrood disease in honeybees.