Fantastic Yeasts and Where to Find Them
2019: We are currently recruiting primary schools to take part in a large project starting September 2019, where we hope to collect soil samples from all counties in Ireland. Look out for an email!
Welcome to the Wild Yeast Project at University College Dublin. Did you know that there are more organisms in a teaspoon of soil than there are people on the entire planet? In this project, UCD students survey the yeasts living in Irish soil. Yeasts are fungi – they belong to the same family as mushrooms. However, yeasts often have have only one or a few cells, so they are easier to work with, and to grow in the lab. We don’t know what kinds of yeasts live in Irish soil, but we do know that they are required to keep the soil healthy. Climate change may affect the yeasts, so we want to find out what kinds (species) are living here as soon as possible.
This project is part of two third year undergraduate research modules. Starting in 2017, undergraduate students collected soil samples from around Ireland, and used microbiological and genetic techniques to identify yeast species living in the soil. They chose 8 interesting species, and sequenced their genomes (i.e. examine all their DNA). They also learned how to analyse the data from the genomes.
In 2018, some school children and friends of UCD helped to collect soil samples. In the map below, you can see all the sites that soils were collected from. The blue X’s show samples where we did not identify yeasts, and the purple stars are sites were we did identify yeasts.
To see more detail, click on the arrow beside “Yeasts 2018-2019”. If you helped with the project, you should be able to find your name, either at the down facing arrow beside “Other soils tested”, or the one beside “Yeasts identified”. If you click on your name, it will show you the name of any species that we identified from your sample. It might be easier to go to a bigger version of the map here.
You can click on each location to see what we found.
What is living in your soil? The picture below shows some of the organisms that grew. Some of these are bacteria, some as filamentous (fuzzy) fungi, and some (marked with an arrow) are yeast…
People that helped to collect soil
Boys from Mr Lyons 4th Class, St Mary’s Boys National School, Rathfarnham. Darragh McKenzie took some soil from the playing field at the back of the school, and we identified the yeast Lodderomyces elongisporus in the soil. The Butler lab at UCD is interested in this yeast because it closely related to other species that cause disease (though Lodderomyces is not dangerous). Seán O’Farrell took some soil from his back garden, and we found Kazachstania servazzii living in it. Kazachstania was named by a woman scientist called Zubkova, who isolated it for the first time in Kazakhstan in 1971. Kazachstania sometimes spoils food (make food and drinks sour). We chose Seán’s yeast for further investigation, so maybe we will find more interesting information!
Isobel and Eoin Butler from St Oliver Plunkett’s School in Balrothery collected soil from a wheat field in Meath (Isobel) and their back garden (Eoin). We found Aureobasidium pullulans in Isobel’s sample, and Solicoccozyma terricola in Eoin’s. There are pictures of what these look like under the microscope below. Can you see that they both have single cells with small daughter cells “budding” off? The cells from the two species are very different sizes.
Aureobasidium pullulans is often found near plants (maybe the wheat in the field), but it doesn’t cause any harm. Solicoccozyma terricola is often found in leaf litter in forests, and it’s not completely known what it does.
The undergraduate students chose several species for genome sequencing. These were followed up from January-May 2019. The species chosen are:
Papiliotrema frias: isolated from a park in Crumlin in Dublin. This is only the second time that this species was isolated. It was first found in a glacier in Patagonia (Argentina) and it was assumed to live only in very cold places.
Taphrina betulina: isolated from the shore of Lough Corrib. This yeast causes “witches brooms” to form in trees, which look like messy bird’s nests.
Vishniacozyma victoriae: isolated from several places. This was first identified in glaciers, but it is now known to be common in soils in Europe. Not much is known about the lifestyle of this species.
Naganishia diffluens: found in two different places. Relatives of this yeast have been used to make biodiesel.
Symmetrospora coprosmae: isolated from a public field in Dublin 8. This species seems to have been isolated only once before, from a leaf in New Zealand in 1995.
Saitozyma podzolica: isolated from a suburban garden in Dublin. This species is found in soil all over the world, and might be able to break down plant material.
Kazachstania servazzii: found in two places. This species can spoil packaged foods like pizzas, by making lots of gas. The students have prepared 3 scientific papers describing some of these species, and they will be submitted for publication over the summer.
In 2017/2018, UCD undergraduates identified a new yeast species, never seen before. They called it Hanseniaspora scholastica, and you can read more about this here. They also published some scientific papers describing their other work.