Learning how to grow symbiotic fungi


UCL’s Mycology Laboratory is a world leader in the in vitro breeding of a certain fungus of great value to agriculture and research. Each year, Prof. Stéphane Declerck’s team shares its knowledge with people who come to UCL from all over the world. 

Truffles, boletes and other chanterelles are mycorrhizal fungi—fungus and vascular plant roots that have teamed up to grow together—which is one of three large fungus categories1 studied within the UCL Mycology Collection. Another mycorrhizal fungus, invisible to the naked eye, is the arbuscular mycorrhizal fungus, which teams up with the roots of 80% of plants. ‘The arbuscular mycorrhizal fungus is not in the least a parasite’, explains Prof. Declerck, Head of both the UCL Mycology Laboratory and the Mycology Collection.2 ‘It lives in symbiosis with the plant and helps it repel attacks, such as disease and pollutants. Some plants, such as most orchids, can’t live or grow without mycorrhizal symbiosis.’

An very useful little fungus

Arbuscular mycorrhizal fungi are very useful in agriculture and horticulture, especially of the organic variety. Indeed, they naturally protect and foster plant growth, reducing the need for pesticides and fertilisers. The agri-food industry isn’t the only interested party. ‘In fundamental research (such as genetics and cellular biology),’ says Prof. Declerck, ‘we study arbuscular mycorrhizal fungi to understand how the fungus and the plant talk to each other. Their symbiosis has existed for 450 million years. Fungi enabled plants to spread from the marine environment to land.’ That’s part of why scientists want to take a closer look.

Uncontaminated breeding

In the wild, arbuscular mycorrhizal fungi grow in association with roots but can be contaminated by air-borne microorganisms, including bacteria and other fungi. In the late 1990s, UCL’s Mycology Laboratory, in association with international institutions, developed a unique in vitro breeding technique. Prof. Declerck explains, ‘First, we isolate an arbuscular mycorrhizal fungus spore and disinfect it. Next, we place it beside a root in a sterilised(at 121°C) and gelled environment in a Petri dish that contains all the minerals necessary for growth. After a few weeks, the fungus colonises the root and grows in aseptic conditions—in other words, safe from undesirable contamination.’

In the end, in vitro breeding makes possible the reliable use, observation, study and analysis of ‘clean’—uncontaminated by microorganisms—arbuscular mycorrhizal fungi.

Mycothèque formation internationale

International training

The technique has attracted wide interest: companies, universities, scientists, engineers. Faced with such demand, the Mycology Laboratory began offering training in the early 2000s. Ever since, once or twice a year, a group of at most 12 participants come to UCL to learn how to breed arbuscular mycorrhizal fungi in vitro, including spore disinfection, inoculation, marrying and other techniques, as well as optional sessions that delve more deeply into the study of fungi. Prof. Declerck and colleagues published a book on the subject.3

‘For us,’ Prof. Declerck says, the first advantage of the training is that it helps us organise upstream, because it mobilises all Mycology Laboratory personnel during one week. Second, the money it earns helps pay for equipment and fund projects. So everybody wins.’4

Candice Leblanc

(1) The two other categories are filamentous fungi (such as moulds, wood-decay fungi) and yeasts.  

(2) The UCL Mycology Collection holds 30,000 fungus strains, making it one of the world’s largest fungal collections.

(3) Declerck, S., Strullu, D.G and Fortin, J.A., In Vitro Culture of Mycorrhizas, Heidelberg, Springer-Verlag, 2005, 386 pp.

(4) The training fee varies from €1,500 for university students to €3,000 for private companies. It includes five days of training, lunches, documentation and a sociocultural activity.

A Glance at Stéphane Declerck's bio

Stéphane Declerck

1992                       Degree in Agricultural Engineering, UCL
1996                       Doctorate in Biology and Plant Physiology, Université d’Angers (France)
1996-2004              Researcher, Microbiology Unit (Mycology Collection), UCL
2004-12                  Associate Professor, UCL
Since 2006             Director, Mycology Collection, UCL
2006-11                  Head of Microbiology Unit, UCL
Since 2012             Professor and Head of Mycology Laboratory, UCL
2013                       Winner of Prix Bauchau

Published on November 10, 2016