Scientists document the bizarre mating habits of TRUFFLES in an effort to make them easier and more reliable to grow in farms
- Unlike many other types of fungi, truffles actually reproduce sexually
- Scientists have learned truffles need a male and female pair to reproduce
- One of the main obstacles to truffle reproduction is their tendency to kill members of the opposite sex that encroach on their territory
The mystery of truffle reproductive habits has helped keep the culinary delicacy relatively difficult to farm, but researchers have steadily been working to understand the sex lives of truffles so that farmers can more reliably grow them.
Other fungi, like mushroom, reproduce asexually by spreading their spores through the air.
For years researchers thought truffles reproduced in a similar fashion, by spreading their spores not through the air but through the feces of the dogs or pigs that would dig them out of the ground.
The reproductive habits of truffles have long been a source of mystery for researchers
In 2008, Frencesco Paolocci, a researcher from the Institute of Biosciences and Bioresources in Perugia, Italy discovered the common wisdom was wrong and truffles are very much sexual entities.
According to a report in New Scientist, Paolocci discovered that truffles were also split into male and female forms, and could only reproduce when a member of each sex partnered.
A female partner would deliver nutrients to the new tissue and a male partner to deliver DNA.
Within each sex are a further two distinct mating types, named MAT 1 and MAT 2, which need to be paired before reproduction can begin.
Unfortunately, different truffle types are more likely to kill each other than to reproduce when put in close proximity with one another.
This is because truffles are part of a much larger system of wispy white roots known as a mycelium, which spreads out across the forest floor like a thicker sort of spider web.
Unlike many other fungi, truffles actually reproduce sexually rather than asexually, though they’re often as likely to kill potential partners for encroaching in their territory
The Mycelium draws nutrients from tree roots and feeds small nodes of truffles underground.
When mycelium from a different mating type encroaches on the territory of another, they appear to induce a kind of necrosis in one another to protect their host tree.
‘They don’t have their sexual partners around,’ truffle researcher Marc-André Selosse told New Scientist.
‘It’s like having cities of only men or only women.’
Adding to the mystery, male truffles appear to be difficult to trace and tend to only reproduce once or twice before disappearing.
The current theory is that male truffle spores lie dormant in the soil and only germinate after a genetically similar female truffle spreads across a nearby root.
This could help explain the comparative genetic similarity between parent couples in truffles.
‘The fathers are genetically very close to the mothers, and we know that the more physically close they are, the more genetically close,’ Selosse said.
HOW DO YOU GROW TRUFFLES?
Historically, truffles were simply ‘found’ and could not be grown.
They were often tracked down by Truffle pigs that had an excellent nose for the fungus.
In the 19th century, many of the attempts at cultivating the truffle failed miserably.
French gourmet Jean Anthelme Brillat-Savarin once called truffles ‘the diamond of the kitchen’.
In 1825, he said: ‘The most learned men have sought to ascertain the secret [to growing truffles], and fancied they discovered the seed.
‘Their promises, however, were vain, and no planting was ever followed by a harvest.’
The truffle fungus requires a host, often the roots of a tree in order to grow properly.
Truffles are produced by inoculating the seeds of trees with the fungus.
This fragile process occurs in a greenhouse and can take some time, the trees are then planted and as the plant grows, so do the roots and, as a result, so do the truffles.
The tubers can then be harvested when they are fully developed.