Shedding light on the mysterious fungus kingdom
“All fungi deserve their rightful place in the fungus kingdom,” according to Henrik Nilsson, who is campaigning for the world’s six million species of fungi to all be given names. As a dedicated mycologist, and one of the University’s most frequently cited researchers, he has made crucial contributions to achieving this goal.
There is a rustling in the autumn leaves in the Gothenburg Botanical Gardens. Henrik Nilsson is holding a polypore fungus that he has just picked from a stump, and he waves his hand over the ground.
“If you took a teaspoon of soil from here, you would pick up about a hundred fungi, and probably half of them have no name. There is so much that we don’t know. Just think that a species can be 1.5 billion years old, and we have no idea what it is, what it does and why we can’t grow it. This fascinates me. I’ve always wanted to shine a spotlight on these unknown fungi,” he says.
Henrik Nilsson is a mycologist, or as he puts it, his job involves: “the science of the great, mysterious and often overlooked fungus kingdom”. A universe of around six million fungi which, according to Henrik, deserves much more attention, and where we are currently missing out on a lot.
The big challenge, which he has spent most of his research career addressing, is that the rules for categorising and naming fungi are not adapted to what we now know to be the nature of the fungi world. According to the current rules, for a fungus to be given a scientific name, it must have a fruiting body, or it must be possible to grow in a laboratory. But that is not what reality looks like for fungi.
“Fungi ought to be thought of as more or less subterranean and mostly hyphae-based organisms, which are essentially invisible. Far from all fungi form a fruiting body, or can be cultivated. This means that we have a system of rules that excludes the majority, at least two thirds, of all fungi,” he says.
The fact that so many varieties remain unknown creates several problems, Henrik points out.
“Fungi without names cannot be offered such extensive environmental protection rights internationally as those that have been named, and they are also overlooked in research. Actually, it’s quite bizarre. I mean, what if we were to draw a line through the periodic table and say: ‘the elements to the right of the line, nope, we don’t care about those’,” he says.
But the way we think about fungi is changing, and Henrik Nilsson has made significant contributions to this trend. Key in this is DNA sequencing, a method used by an increasing number of mycologists. The examination of genetic information provides more reliable, more extensive knowledge about different fungi.
Henrik Nilsson and a group of northern European research colleagues have seized on the opportunities offered by DNA-based information to develop the UNITE database. This database makes it possible to systematically register and retrieve information on all fungi, even those without a name, and it is now more or less a standard tool in mycology.
“Since many fungi do not have a scientific name, we give them a digital object identifier, a DOI, instead. This makes it possible to see information about where the fungi were found for example. This does not fully solve the naming problem, but at least we can now communicate about the fungi in a consistent way. I hope the database can help speed up the process and discussion around finding a better system of rules for identifying and naming fungi, that also includes DNA sequencing,” he says.
Currently, the database contains around 1.5 million DNA sequences and nearly 150,000 different species of fungus, and it is constantly growing. And the system also highlights the unnamed fungi to some extent. Henrik Nilsson and his colleagues have created an app that lists the fifty most wanted fungi that have no scientific name.
“In pace with DNA being used more and more to map our living world, and researching fungi being incorporated into various ecological studies for example, the database has also started being used by non-mycologists. It’s great to see that areas like conservation and agriculture are benefiting from the database, even if we’re doing this primarily for the sake of the fungi,” he says.
Another effect of the database, which Henrik Nilsson had not expected at all, is that he has been on the list of the most frequently cited researchers in the world for several years. This is largely because many studies using DNA-based identification choose to cite his articles.
“I’m delighted, but it’s not something I ever expected. I like the fact that things I do are being used, and the citations are a form of acknowledgement that I have somehow had an impact in the wider world,” he says.
When do you think all the world’s fungi will have a name?
“I feel that mycology is moving towards a future of innovative thinking that will cause it to flourish, but it is moving there very slowly. It will probably take another 20 years before the DNA aspect has a given place in the rulebook.”
THEN: Fungi have always played a major role for humans, but the scientific study of fungi, mycology, has always been somewhat side-lined. By tradition it was relegated to the plant kingdom for a long time, and it was only in the latter part of the 20th century that it became generally accepted that fungi constituted a kingdom of their own. For a long time, the classification and systematisation of fungi relied on their appearance (morphology), a source of information that does not function as well in the fungus kingdom as in the plant kingdom.
NOW: The use of DNA sequencing in mycology has brought about major changes in the way we systematise or even perceive fungi. We now know that fungi are everywhere, even in lakes and seas, and what appears to be the majority of fungi do not seem to form any noticeable fruiting bodies at all. Many of these newly discovered, almost invisible groups of fungi cannot be grown in the laboratory, sometimes because they form intricate symbiotic relationships with other organisms.
IN THE FUTURE: Molecular methods are helping us to get better at studying what fungi actually do in nature, and their importance in the ecosystem is turning out to be far-reaching. We are moving towards a future in which expertise in mycology will be needed in a wide range of scientific fields, just as we know today that we will never be able to understand the fungus kingdom unless we look at it in terms of our knowledge of other groups of organisms. Retaining traditional, morphology-based knowledge in the era of DNA biology is a challenge for mycology.