Gap closed in the genetic map of kingdom fungi

Sep 20, 2013
Mycelium: a network of Pyronema confluens cells. The detail indicated here has a length of about 120 micrometres. Credit: Stefanie Traeger

An international research team headed by PD Dr Minou Nowrousian from the Ruhr-Universität Bochum (RUB) has sequenced the genome of the ascomycete Pyronema confluens, thus closing a gap in the genetic map of fungi. For the first time, scientists have shown for fungi that, in the entire genome, those genes that are active during the sexual development evolve more rapidly than other genes. A similar effect was already described for animals and plants; for fungi, however, this question had hardly been addressed at all. The team from Germany, Spain and the USA has published their findings in PLoS Genetics.

Pyronema – a typical representative of its systematic group

Today, the genomes of more than 250 have been sequenced. Among the basal filamentous ascomycetes – a group of ascomycetes that includes e.g. truffles and morels – only one representative has been analysed so far: the truffle Tuber melanosporum. "With 125 million , the truffle is unusually big, yet it is coding for relatively few genes, namely some 7,500," says Minou Nowrousian from the Department of General and Molecular Botany. "Until now, it was not clear whether this is typical of basal filamentous ascomycetes or whether it is caused by the truffle's 'atypical' lifestyle." Unlike other filamentous ascomycetes, the truffle does not develop – so-called fruiting bodies – above ground but rather below ground. Moreover, it only grows in symbiosis with (mycorrhiza). Pyronema, on the other hand, is a typical representative of its group.

Intermediary evolutionary stage

The genome of Pyronema confluens contains 50 million base pairs and some 13,000 genes; it is thus smaller than that of the truffle, and yet it contains more genes. These findings confirm the truffle's special position and provide new insights into the evolution of ascomycetes. "Pyronema confluens bears a stronger resemblance to higher ascomycetes than to the truffle," concludes Minou Nowrousian. However, the scientists have also discovered differences to higher ascomycetes, for example in the DNA sequence containing the genetic blueprint for mating type genes. Mating type genes are the main regulators of and, in Pyronema confluens, they do not show the standardised structure that is typical for higher ascomycetes. "Pyronema confluens may represent an intermediary evolutionary stage in the evolution of mating type genes," says the Bochum biologist.

Light-activated genes

One characteristic feature of the fungus under investigation is the fact that it produces fruiting bodies only in light. Fittingly, the researchers discovered genes in the Pyronema genome containing blueprints for photoreceptors for different wavelengths of visible light. The activity of some of those genes increased in light.

Explore further: New species of truffle found in Finland

More information: Traeger S, et al. (2013) The genome and development-dependent transcriptomes of Pyronema confluens: a window into fungal evolution, PLoS Genet 9(9): e1003820. DOI: 10.1371/journal.pgen.1003820

add to favorites email to friend print save as pdf

Related Stories

New species of truffle found in Finland

May 16, 2013

A species of truffle that is considered to be rare has been found for the first time in Finland. Previously it has been thought to exist only in the Pacific Northwest region of the United States. The truffle ...

Scientists scent breakthrough in truffle trafficking

Mar 28, 2010

One of Europe's gastronomic jewels, the fabled black Perigord truffle, has been genetically unravelled, a feat that could doom fakers who pass off inferior truffles as the real thing, scientists said on Sunday.

Scientists reveal the sex wars of the truffle grounds

Oct 25, 2010

They are one of the most highly prized delicacies in the culinary world, but now scientists have discovered that black truffles are locked in a gender war for reproduction. The research, published in New Ph ...

Recommended for you

Deadly human pathogen Cryptococcus fully sequenced

Apr 17, 2014

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...