UPWr researcher discovers new species of fungus

The UPWr scientist came across the track of Colletotrichum acericola during her research for her PhD. She found the fungus on Krakowska and Bytomska streets in Wrocław, on the seeds of an ash-leaf maple. It caught her interest because, as she admits, it did not match any previously known species. – That is why I decided to take a closer look at it, and thanks to the cooperation with the Polish Academy of Sciences – Szafer Institute of Botany and the Institute of Nature Conservation, as well as with the Bydgoszcz University of Technology, it was possible to describe this 'Wrocław' species of fungus – says Dr Katarzyna Patejuk.

She adds that the fungus was interesting because it differed genetically from its closest relatives: the Colletotrichum agaves complex (this is a very narrow complex and, apart from one finding in Europe, on a commercial plant, it has not yet been recorded on wild European plants).

Fungi of the genus Colletotrichum are generally known as endophytes, i.e. species that live inside plant tissues without harming them and as economically important plant pathogens, causing so-called 'anthracnose'. "Wrocław's" fungus was found on an alien and invasive tree species, the ash-leaf maple, which threatens our local environment by, among other things, crowding out native species.

– Genetic studies of the Colletotrichum acericola have indicated that identical ITS sequences (i.e. gene sequences typical of the fungal kingdom, within which the most rapid changes occur and serve as the first step in any taxonomic study of these organisms) as in our species have been isolated in the USA, from the prairies of Minnesota, Illinois and Indiana. And this could mean that the fungus is native to North America and probably arrived in Europe on its host, the maple tree – says Dr Patejuk. And she stresses that this is of huge importance from a conservation point of view: firstly, the pathogen of the ash-leaf maple may weaken its invasiveness and expansion (a good thing), but it could also potentially pose a phytosanitary threat to our local, native maples – the sycamore or the common maple.

– This fits in with the so-called spillover phenomenon, when a newly arrived pathogen can jump onto local native species, but by not being used to the pathogen, it has a much stronger and worse effect on them, compared to the invasive plant with which it shared years of coevolution – explains Dr Katarzyna Patejuk. – A similar situation occurred with the grey squirrel's transmission of squirrel poxvirus, which has meant that our native red squirrel is now in retreat, as the virus is decimating its population. We are currently conducting research to rapidly detect this threat and protect our native maples. The results are promising. This is important because although Colletotrichum acericola was discovered in Wrocław, it is likely to be much more widely distributed – emphasises the UPWr scientist.

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