Section

Colletotrichum (Ascomycota, Sordariomycetes, Glomerellales) is a very large fungal genus (> 800 species) that causes numerous economically important plant diseases worldwide, for example necrosis on fruits, leaves and stems of herbaceous and woody plants that are known as anthracnose, The genus also comprises endophytes that could be beneficial for plant health. Therefore, a correct species differentiation is crucial. However, the species can hardly be identified by morphology, and no living cultures or DNA are available of most species.

In order to study the systematics of Colletotrichum species, the fungi are cultivated on artificial media and characterised regarding cultural appearance and microscopical features like fruit bodies, conidia and appressoria. Phylogenetic trees are calculated on the basis of multilocus DNA sequence data (at least six loci). Species are differenciated by considering all available data (polyphasic approach).

The revision started 2008 at CBS-KNAW Fungal Biodiversity Centre (now Westerdijk Fungal Biodiversity Institute) in Utrecht, the Netherlands, and continues since 2014 at Senckenberg in collaboration with specialists from all over the world. To date, important species complexes were recognised and studied, the systematic position of many species (including the type species, C. lineola) clarified and about 80 new species described. In addition to working on further species complexes, the species diversity of certain host plants and biotopes in different countries is examined and entire Colletotrichum strain collections are revised, with new species constantly being discovered. An online data base for identification of Colletotrichum species on the basis of multiple DNA sequence data was developed and is regularly updated (https://qbank.eppo.int/fungi/).

Fungi can locally necrotise and clog the vascular system in wood, which can lead to the inhibition of growth, fructification, wilting and dying off of branches and whole trees and reduces the fruit yield. The spektrum of ascomycetes, that cause necroses in the wood of fruit trees is very large and comprises species of many diverse genera, e.g. Diplodia, Eutypa, Phaeoacremonium und Diaporthe. As these ascomycetes grow inside the wood and rarely sporulate or form fruit bodies, they are very difficult to identify and are to date little studied.

Previous studies include the spektrum of ascomycetes in the wood of fruit trees in South Africa and resulted in the discovery of several new species in different genera. As there are little data from Germany, this topic is now studied as part of the project “German Barcode of Life – Bridging the gap between science and practice (GBOL-2) –  Fungal pathogens & necrotic fungi in orchards”. The aim is the exploration of the fungal diversity in Germany, and also the collaboration on the development of a DNA-based diagnosis system for fungi (EcoChip).

Barcodes of microfungi are generated that are isolated from necroses in wood of fruit trees. Since even in Germany, a large proportion of the fungi in the wood of fruit trees are still unknown, so far only about half of the >170 differentiated species could be identified with certainty to the species level ; some of the new taxa have already been described. The GBOL project, which has been running for a number of years and in which other SGN research groups are/were already involved, received an award from the UN Decade on Biodiversity in 2016.

Biodiversity and biogeography of fungi have been in the focus of the Section Mycology for years, especially mapping of fungi in Saxony and of phytopathogenic microfungi (powdery and downy mildew pathogens, rost and smut fungi, anthracnose pathogens etc.). The occurrence of the genus Colletotrichum in Germany is also being investigated, which requires cultivation and DNA sequencing of the fungi. The focus here is initially on the species diversity on strawberries.

Continuous monitoring of the changing variability range of pathogens or pathogen types, allows for example an early detection of the occurence of new pathovars on cultivated plants. Particularly under the aspect of changing climatic conditions, the herbarium is a reliable and sustainable form of documentation of inventory as well as shifts in the distribution of fungi. At the same time, it provides a wide-range gene resource for specialised molecular studies. By means of DNA sequence data, taxonomic problems can be solved that allow an expanded understanding of host-fungus relationships.

The mycological collection at the Senckenberg Museum of Natural History Görlitz (Fungarium; GLM-F) is part of the Herbarium Senckenbergianum. The collection has its origin in the historical collection of the ‘Naturforschende Gesellschaft der Oberlausitz’, which, however, was lost to a large extent during the first half of the 20th century in consequence of war. Beginning in 1974, a systematic re-establishment of a mycological collection was initiated by the curator Ingrid Dunger, with the strong support of Ch. Stark, Görlitz and G. Zschieschang, Herrnhut.

The collection has since then been continuously expanding, by means of collection activities by the staff itself as well as intensive contributions from a number of citizen scientists. A further major factor is the acquisition of scientifically valuable material from private herbaria. The extensive digitalisation of the mycological collection is owed to the former head of Section Mycology, H. Boyle. Since September 2005 all collection data are available on the Internet via GBIF (Global Biodiversity Information Facility), where they are continuously updated and available for scientific purposes.

Presently, the fungal collections in GLM consist of more than 136,000 specimens belonging to diverse ecological and phylogenetic groups of fungi. Phytopathogenic microfungi such as rost and smut fungi as well as powdery mildew pathogens are a speciality of this collection, represented by a large part of the specimens, followed by wood-colonising macrofungi such as polypores and corticoid fungi.

The collection also contains organisms that are not true fungi, especially downy mildew pathogens and so-called slime moulds belonging to the Heteroconta or Amoebozoa, respectively. The latest specimens are dried cultures of phytopathogenic microfugi that had been isolated from plants, especially from wood necrosis of fruit trees, and cultivated on artificial culture media. These fungi are also maintained in a culture collection that serves as the main basis of research and teaching and includes more than 2,500 living strains.

More than half of the specimens were collected by citizen scientists, especially H. Jage,  F. Klenke (phytopathogenic microfungi), G. Zschieschang, S. Hoeflich, F. Gröger, G. Künst­ler (macrofungi), Ch. Stark, J. Schwik (wood-colonising macrofungi), F. Dämmrich (corticolid fungi), M. Eckel and H. Gottschalk (slime moulds, Ascomycetes). Special emphasis is given to the contributions of H. Jage, Kemberg (picture left below), who continuously collected phytopathogenic microfungi for decades and has an excellent knowledge both of plants and fungi. With approx. 60000 specimens in GLM (many of them are not yet incorporated in the collection), he is not only the most important collector of the Fungarium, but also one of the most important collectors of the Herbarium GLM. The unremitting collecting activities of the curators focused in the past mainly on wood-colonising macrofungi (I. Dunger; picture left above) and phytopathogenic microfungi (H. Boyle).

One of the main functions of the fungal collection Görlitz is the documentation of occurence and conservation of fungal species in the region; the data are part of the current Red Lists of threatened species and species lists of fungi in Saxony and in Germany. Another important task is the safe storage of type specimens (to date about 120 types), on the basis of which new species have been described. Speciens, especially of the collection of phytopathogenic microfungi, are regularly loaned to other specialists for taxonomic revision of specific genera and species. In the past, the collection was also basis for taxonomic research of the basidiomycete genus Hebeloma.Currently, species of the genus Colletotrichum as well as Ascomycota isolated from necrotic wood of fruit trees are studied taxonomically on the basis of multi-locus DNA sequence and morphological data by the Section Mycology.

This collection is part of the Herbarium Senckenbergianum.