On the road to understanding truffles in the underground.

The genome of the ectomycorrhizal ascomycete Tubermelanosporum has recently been published and this has given researchers unique opportunities to learn more about the biology of this precious edible fungus. The epigeous ascomycete lives in Mediterranean countries in symbiotic interaction with roots of broad-leaf trees such as oaks and hazel. A most important new finding was the single mating type locus in the genome that occurs with two alleles in natural populations. The life cycle is now confirmed to be heterothallic and the species is outcrossing. Unlike sexual development in the soil, mycorrhization of the roots by homokaryotic haploid mycelia is mating-type-independent. Gene regulation during mycorrhization and fruiting and environmental influences on it is now genome-wide addressed. Genome profiling for functions in specific metabolic pathways is undertaken. Insights in most enthralling features of tubers such as on odor formation are thus gained.