Truffles’ smell of success is in their genes

In the paper published online this week in Nature Ecology & Evolution (Murat et al., 2018), an international team led by Francis Martin, among which two Researchers at IPSP-CNR, Raffaella Balestrini and Antonietta Mello, has sequenced the genomes of the Piedmont white truffle (Tuber magnatum Pico) and the Burgundy black truffle (Tuber aestivum), as well as of lesser-known edible fungi such as the desert truffles (Terfezia boudieri), of pig truffles (Choiromyces venosus), and the genome of a black morel (Morchella importuna). Comparing these genomes with those of the already sequenced Perigord black truffle (Tuber melanosporum, Martin et al. 2010, Nature) the authors find unexpected genetic commonalities between the white and black truffle species, despite their separate evolutionary paths since their divergence over hundreds of millions of years. They also find that truffles have a limited set of the genes that allow other fungi to specialize in breaking down the cell walls of the plants on which they live. Instead, truffles finely tuned the expression of genes that produce smelly volatile organic compounds, generating the pungent aroma that attracts animals (famously pigs and truffle dogs) to disperse the truffle’s spores.