A recent paper in the journal PeerJ has demonstrated the incredible yet unknown diversity of life that may be lurking on the shelves of your local grocery store.

Dried porcini mushrooms Image: Wikimedia Commons

When Rachel Mason Dentinger popped down to a London market to purchase a few ingredients for dinner she had no idea that she might actually be discovering several new species!

Among Dentinger's dinner ingredients was something that would look to most people like a perfectly ordinary packet of dried porcini mushrooms ... unless you're a fungi expert – and Dentinger's husband happens to be world-renowned mycologist Dr Bryn Dentinger, working at at the Royal Botanic Gardens, Kew, in London. He decided to take a random sample from his would-be dinner and used a technique known as DNA barcoding to look at the genetic variation within the porcini mushrooms (because ... who doesn't DNA-sequence their dinner?).

Once the genetic analysis was complete, it turned out that Dentinger and his colleague Dr Laura Martinez-Suz had found three brand new species of porcini mushrooms.

But why were there that many different species lurking within just one packet of dried mushrooms? To be sure, it was a surprising turn of events ... but the scientists weren't completely floored by their discovery. That's because the porcini genus of mushrooms (Boletus) displays an incredible amount of diversity in the wild – and it's actually wild porcinis that end up on our plates.  

Most crops (like wheat, corn or carrots) are cultivated in monoculture – meaning vast swathes of land are planted with one single species of crop (often a genetically modified one). Porcini mushrooms, however, have so far proven impossible to cultivate. And here's why.

The mushroom we see above ground is just the 'tip of the fungus iceberg' Image:Matthew Kirkland/Flickr

Fungi are much like icebergs: the bit you see (the mushroom, or 'fruiting body' to use the correct terminology) is only a tiny percentage of the actual mass of the organism – the main body of the fungus is actually a huge mat of microscopic tubes (called mycelium) that spread out through the substrate searching for nutrients. To ensure easy access to food across such a vast space, fungi often form symbiotic relationships with nearby trees and plants, giving water and nutrients in exchange for sugars. 

Because, with very few exceptions, porcinis form these symbiotic partnerships, they can't be cultivated unless the correct partner is present. So the effort (and time) that would go into recreating the perfect porcini plot just wouldn't be worth it. For all of our technological prowess and abilities to genetically engineer organisms, sometimes we just have to bow to Mother Nature. 

Much more so than farmed crops, wild mushrooms have to respond to changes in their environment (there's no one around to regulate things like water, available space or nutrients). A mushroom in one area might have different pressures than a mushroom nearby – and so, over time, we're left with a very diverse, very well adjusted and very cryptic genus being scooped up and packaged for us to purchase at the grocery store. 

"We hope that [our work here] will encourage mycologists with ready access to fresh collections of these species to record and document their characteristics and discover new features that may help to distinguish them," urge the authors.

In a world where many feel there's no new science to do (or that you need billions of dollars and an atom smasher to make groundbreaking discoveries), it's great to see globally important research emerging from something as seemingly mundane as a local market.

"We are grateful to Rachel Mason Dentinger, who serendipitously supported this research through a spontaneous purchase of dried porcini for our dinner," the authors write, in what is surely one of the most amusing and heartwarming acknowledgements in any scientific paper.

Now, who said scientists don’t have a sense of humour? 

Top header image: Stephanie Watson, Flickr