Wild Yeast Project!

Wild Yeast Project!

Fantastic Yeasts and Where to Find Them

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. We have now identified three new yeast species, and sequenced the genomes of 5 species for the first time (with several more ongoing).

In September 2019, pupils at 15 primary schools from 13 counties in Ireland helped us to collect soil samples. You can see the location of the schools on the map below . UCD undergraduate students also collected soil samples.

To see more detail, click on the arrow beside “Schools 2019”.

Children from Castleplunkett NS, Co. Roscommon, collected some soil samples. (you can click on the images to see larger photos).

The undergraduates worked hard to extract yeasts from the soil.

Below are some of the fungi that grew from soil collected by pupils from New Ross Educate Together, Co. Wexford, and pictures of yeast taken down a microscope from soil collected by pupils at Urhan NS, Co. Cork.



What did we find?

We found 16 different yeast species in soil samples collected by primary school pupils in 2019 (see below). We found two that have only been described once before. One is called Ogataea degrootiae, collected by pupils from Kilglass NS, Co. Sligo. This species was discovered in 2018 by school pupils in the Netherlands (see here). Another species is called Hanseniaspora scholastica. We found this twice in 2019, in soil samples collected by pupils from St Bernard’s NS in Co. Longford and from Kilcommon NS in Co. Tipperary. Hanseniaspora scholastica was first isolated by UCD students in 2017, and hasn’t yet been described in other countries (see here). We now know that Hanseniaspora scholastica is probably quite common in Ireland. No other study has worked out all the letters in the DNA instructions (called sequencing the genome) for Ogataea degrootiae or Hanseniaspora scholastica.

The undergraduate students found some more species in different soil samples, including Candida tropicalis, which can cause disease in humans. They also found what appears to be two new Candida species, one from a wormery, and one from soil. These have not yet been named.

The undergraduates have chosen to sequence the genomes of Ogataea degrootiae, the two isolates of Hanseniaspora scholasticathe two new Candida species, and some isolates of Candida tropicalis. Apart from Candida tropicalis, this will be the first time that the genomes of these species have been sequenced. 

Species identified soil samples from schools (species in bold chosen for further study)

St Finians NS, Garryhill, Co. Carlow: Pichia fermentans, Schwanniomyces capriotti, Candida sake, Kazachstania servazzii

Urhan NS, Co. Cork: Barnettozyma californica, Kazachstania servazzii, Cyberlindnera suaveolens 

Leap NS, Co. Cork: Hanseniaspora uvarum

Knockaderry NS, Co. Kerry: Wickerhamomyces anomalus

Allen NS, Co. Kildare: Wickerhamomyces anomalus

Abbeyleix South NS, Co. Laois: Vanrija albida

St. Brigid’s NS, Co. Limerick: Barnettozyma californica

St. Bernard’s NS Co. Longford: Kazachstania servazzii, Hanseniaspora scholastica

Whitecross Primary School, Co. Meath: Torulaspora delbrueckii

St. Ciarán’s NS, Co. Offaly: Saccharomyces paradoxus, Kazachstania servazzii

Castleplunkett NS, Co. Roscommon: Wickerhamomyces anomalus

Kilglass NS, Co. Sligo: Naumovozyma castellii, Ogataea degrootiae, Saccharomyces paradoxus

Kilcommon NS, Co. Tipperary: Hanseniaspora uvarum, Hanseniaspora scholastica, Saccharomyces paradoxus, Barnettozyma californica

New Ross Educate Together NS, Co. Wexford: Candida tropicalis

Gorey Educate Together, Co.  Wexford: Kazachstania servazzii, Kazachstania marxianus, Hanseniaspora uvarum, Torulaspora delbrueckii

What we have done from 2017-2020

Identified 3 new species (Hanseniaspora scholastica and two new Candida species not yet named).

Sequenced and published the genomes from isolates of 6 yeast species, 5 for the very first time. You can link from the species name to the publication.

Taphrina betulina (witches broom)

Kazachstania servazzii

Symmetrospora coprosmae

Metschnikowia pulcherrima

Nadsonia starkeyi-henricii

Barnettozyma californica