Two, uncultured cryptic fungal cells recovered from the university pond; cells are labelled green, tails labelled red and DNA labelled blue.
Image: Dr Thomas Richards.

Exeter researchers secure funding to sequence cryptic fungal genomes, one cell at a time

Funding from the United States Department for Energy, Joint Genome Institute (DOE JGI) has been awarded to an international team of researchers, including Dr Thomas Richards, to sequence the genomes of “uncultivable fungi” sampled directly from the environment.

Exeter researcher Dr Thomas Richards formed part of the team which, in 2011, used DNA tagging microscopy to investigate the biology of a new group of fungi sourced from the University pond, adding a previously uncharacterised branch to the tree of life and gaining media attention.

Excitingly, these findings suggested this group, named Cryptomycota (hidden fungi), may account for as much as 50% of the diversity of the fungal kingdom that has, until now, been largely a mystery as these microorganisms cannot be grown in a laboratory.

This newly investigated group is unique compared to studied fungi in that they seem to lack a chitin cell wall for most of their life-cycle. This ‘dinner jacket’ was previously considered essential to the success of the fungi, allowing them to out-compete other microbes in obtaining nutrients and growth.

The funding, recently secured by Dr Richards and collaborators at the University of Michigan and University of California, Riverside, will allow the genome of these microbes to be sequenced for the first time by isolating single cells directly from environmental samples.

Dr Richards commented, “The cells we want to sample are tiny, less than 200th of a millimetre in diameter; using a new approach based on methods developed to study cancer cells we can isolate single representatives of these ‘fungi’ directly from the environment, extract and sequence their DNA. This approach allows us to study the genome of these fungi, the blueprint for how these microbes function in the environment.”

Single cell genomics is a new field of study that promises to revolutionise our approach to evolutionary biology. The University of Exeter - through its Systems Biology initiative - has invested heavily in developing this science.

“Ninety-nine percent of the biological diversity on Earth remains uninvestigated because most microbes cannot be grown in the laboratory. These new single cell approaches promise to allow us to unlock this diversity, complete the tree of life and understand how microbes function, for example how they cause disease”, commented Dr Richards.

Date: 23 October 2014

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