LEONIE LUGINBUEHL & JEONGMIN CHOI
PLANTS AND BENEFICIAL FUNGI
The arbuscular mycorrhizal symbiosis
Welcome to our plant symbiosis website! Looking for the Friendly Fungus Game? See below!
Ever since the transition from water to land, plants have formed a beneficial relationship with a group of fungi called arbuscular mycorrhizal fungi. When nutrients are limited in the soil, plants invite the fungi to colonize their roots and form tree like structures called arbuscules inside the root cells. Fungi forage nutrients such as phosphates, nitrogen, and water from beyond the reach of their host plant’s roots and deliver them to plants in exchange for carbon fixed through photosynthesis. This relationship has been extremely successful for the last 450 million years and is still found in 80% of all land plants on earth. In addition to nutritional benefits, this underground network also confers several ecological benefits, including protection against drought and pathogen attack and increased soil stability. Thus, a better understanding of the mycorrhizal symbiosis is not only scientifically intriguing, but also holds great potential to improve crop production and ecological management.
CAMBRIDGE FESTIVAL: THE ADVENTURES OF A FRIENDLY FUNGUS
Ever wondered what fungi get up to? Did you know that some form friendly partnerships with plants?
Click the green flag below to play your way through the adventurous life of a mycorrhizal fungus, and see if you can complete all of the challenges! Please note: this game is not compatible with mobile devices.
Press the green flag to start
Press the yellow arrows to move through the stages
ABOUT
Our research groups at Cambridge University are particularly interested in the communication between symbiotic partners (plants and arbuscular mycorrhizal fungi) and mechanisms underpinning nutrient exchange. In Cambridge, we collaborate with researchers at the Department of Plant Sciences, the Crop Science Centre, and the Sainsbury Laboratory. Through these collaborations, we aim to advance our understanding on symbiosis to ensure global food supply.
We would like to increase the awareness of the importance and diversity of beneficial fungi in our gardens, in crop fields, and in nature. As part of a public engagement program funded by the Public Engagement Starter Fund from the University of Cambridge, we hope to engage the visitors of the Cambridge University Botanic Garden with this secret, relatively unexplored world beneath our feet and to make them aware of the importance of beneficial fungi in our natural ecosystem.
We hope that the next time people visit the Botanic Garden, they will not only see the beauty and diversity of plants aboveground, but will also be able to imagine the root-fungal network below their feet. - Leonie Luginbuehl and Jeongmin Choi
THE MYCORRHIZAL HOME EXPERIMENT
THE ARBUSCULAR MYCORRHIZAL
HOME KIT
60 chive mycorrhizal home kits were handed out to visitors at the Science Festival in the Cambridge University Botanic Garden in March 2019. With the kit, the visitors performed their own experiment at home. It contained sterilised soil, pots, fungal inoculum, and chive seeds. Half of the kits contained a commercial inoculum (inoculum 1), and the other half contained a different commercial inoculum (inoculum 2 - this pot was labelled with a red sticker). The visitors grew chive plants with and without fungal inoculum to test whether the symbiosis is established with the provided commercial inoculum. They then had the opportunity to bring their chive roots either to a planned stand at the Festival of Plants in May 2019 or directly to our laboratory to confirm the presence of the symbiosis.
RESULTS
To test whether fungal structures were present in roots of the mycorrhizal home kit or garden samples, the roots were first washed with water and put into an alkaline solution containing potassium hydroxide to clear natural root pigments. We then stained the roots with Trypan blue. This is a dye that binds to chitin, a molecule that makes up fungal cell walls, and therefore allows us to see whether fungal structures are present inside the roots.
CHIVES AND INOCULUM 1
CHIVES AND INOCULUM 2
SAMPLES FROM THE GARDEN
CHIVES AND INOCULUM 1
In the negative control (labelled "no fungi"), we only see a weak blue background stain in the roots with vasculature, a tissue responsible for transporting water, mineral and other compounds. However, many of the root samples grown with inoculum 1 clearly show tree-like structures (arbuscules), suggesting that the inoculum worked and the fungus was able to colonise the chive roots! Some roots also contained other fungal structures that resemble a different beneficial fungus called Piriformospora (also called Serendipita). Click on the images below to see the fungal structures in detail.
CHIVES AND INOCULUM 2
In the negative control (labelled "no fungi"), we only see a weak blue background stain in the roots with vasculature, a tissue responsible for transporting water, minerals and other compounds. In most roots inoculated with AM fungal inoculum 2, we observed several small, round, dark blue structures inside the roots. These structures don't look like arbuscular mycorrhizal fungi! Instead, they resemble a different beneficial fungus called Piriformospora (also called Serendipita). This fungus is commonly observed together with arbuscular mycorrhizal fungi, and this would explain why we see these other fungal structures in the roots grown with AM fungal inoculum. The lack of arbuscular mycorrhizal fungal structure in samples inoculated with inoculum 2 may be due to the difference in the substrate. The substrate of inoculum 2 has a very fine structure that makes it difficult for the water to drain properly. We think that this factor inhibited the growth of the chive plants, and might also have affected which beneficial fungus eventually was able to colonise the roots. Click on the images below to see the fungal structures in detail.
SAMPLES FROM VISITORS' GARDENS
In addition to the home experiment, we encouraged the garden visitors to submit root samples from their home garden to monitor the occurrence of arbuscular mycorrhizal fungi in their native environment. Here we present the images of five root samples that we received from the visitors. Now we can confirm that arbuscular mycorrhizal fungi also live in Cambridgeshire, beyond the laboratory and the Cambridge University Botanic Garden.
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THE SYMBIOSIS IN THE CAMBRIDGE UNIVERSITY BOTANIC GARDEN
We also sampled twelve different plant species that grow in the Ecological Mound at the Cambridge University Botanic Garden. We found that the symbiosis is present in almost all the plants we tested. Click on the images below to see the beautiful and diverse fungal structures that grow inside roots of plants from the Botanic Garden!
ACKNOWLEDGEMENTS
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We developed this project in collaboration with multiple institutes in Cambridge. We worked together with Chantal Helm and Pete Michna at the Cambridge University Botanic Garden. Researchers from the laboratories of Uta Paszkowski, Giles Oldroyd and Julian Hibberd in the Department of Plant Sciences and the Sainsbury Laboratory of the University of Cambridge volunteered to engage with the garden visitors at the research pop-up stands during the Cambridge Science Festival and the Festival of Plants. Our funding was provided by the Public Engagement Starter Fund 2018-2019 from the Public Engagement office at the University of Cambridge. We appreciate all our collaborators, volunteers, and funding agency for their enthusiasm and help with our public engagement activities. Finally, we thank all our garden visitors for their keen interest and participation in our research and the outreach program.