Genetic testing needed to ensure truffle growers are producing the intended species

In a recent study published in the journal Mycorrhiza, truffle researchers from the University of Florida and Michigan State University have discovered that some truffle producers in the eastern United States unintentionally cultivate winter truffles (Tuber brumale) alongside European black truffles (Tuber melanosporum). The two species are closely related and share a nearly identical appearance, but the winter truffles sell at a lower price compared to the highly sought-after European black truffles, which are renowned in haute cuisine.

The researchers collaborated with North American truffle farmers and examined specimens from ten anonymous truffle orchards across six states in the eastern U.S. Surprisingly, all but one of the analyzed specimens turned out to be winter truffles. Truffle collectors had sent these specimens for analysis after noticing their unusual characteristics.

To identify the specimens accurately, the researchers utilized genetic testing, as European black truffles and winter truffles are visually indistinguishable. The winter truffle shares the same black, textured exterior and white-veined interior as the European black truffle but differs in price and culinary properties.

Ben Lemmond, the first author of the study and a doctoral student studying plant pathology at the UF/IFAS College of Agricultural and Life Sciences, emphasizes that other truffle producers in the eastern U.S. might also face similar issues. He suggests that growers should consider genetic testing of spores used for inoculation and seedlings to ensure the intended truffle species will be produced in the future.

Matthew Smith, senior author of the study and an associate professor in the UF/IFAS department of plant pathology, explains that truffle orchard owners need to decide how to proceed. They may need to take additional steps to separate the black truffles from the winter truffles. Removing the unwanted truffle species already established in the soil would require uprooting the trees, essentially starting the orchard from scratch. However, even in that scenario, traces of winter truffle spores might potentially remain in the soil.

While winter truffles may lack the prestige of European black truffles, there is still a market for them. Lemmond stresses the importance of accurately identifying the truffle species sold to chefs and consumers, especially now that a new truffle species from Europe has been discovered in North America. He highlights that beyond “black truffles” and “white truffles,” there are over a dozen species of commercially harvested truffles, each with distinct culinary properties.

The study’s authors express gratitude to the truffle growers and collectors who provided the specimens, as their contribution helps enhance the scientific understanding of truffle biodiversity in North America, which remains largely unknown. The researchers appreciate their collaborative relationship with North American truffle growers and the growing truffle industry in the U.S. They believe that working together offers opportunities for meaningful citizen science, student training, and emphasizes the importance of quality control and verification of truffle-inoculated seedlings before planting, benefiting individual farmers and the entire truffle industry.

Source: University of Florida

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