Submitted to: IMA Fungus
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2011
Publication Date: 10/3/2011
Citation: Crous, P.W., Pereira, O.L., Alfenas, A.C., Alfenas, R.F., Rossman, A.Y., Groenewald, J.Z., Minnis, A.M. 2011. What is Scirrhia? IMA Fungus. 2(2):127-133. Interpretive Summary: Fungi cause billions of dollars damage to our agricultural crops and natural resources each year. Knowledge of fungi that cause diseases throughout the world is crucial for preventing the inadvertent introduction of plant pathogens. A fungal pathogen of a fern in Brazil was determined to be a previous undescribed species that is related to a pathogen that occurs on common reed. In this paper the new species and the known pathogen are both described and illustrated. Molecular sequence data are used to determine the relationships of these species to other leaf spot fungi. It is discovered that these leaf spot fungi are closely related despite their morphological differences. This research will be used by plant pathologists and plant quarantine officials to identify these plant pathogenic fungi.
Technical Abstract: The ascomycete genus Scirrhia is presently treated as a member of the Dothideomycetidae, though uncertainty remains to which family it belongs in the Capnodiales within the Ascomycota. Recent collections on stems of a fern, Pteridium aquilinum (Dennstaedtiaceae) in Brazil, led to the discovery of a new species of Scirrhia, described here as S. brasiliensis. Based on DNA sequence data of the nuclear ribosomal DNA (LSU), Scirrhia is revealed to represent a member of Dothideomycetes, Capnodiales, Mycosphaerellaceae. Scirrhia is the first confirmed genus in Mycosphaerellaceae to have well developed pseudoparaphyses and a prominent hypostroma in which ascomata are arranged in parallel rows. Given the extremely slow growth rate and difficulty in obtaining cultures of S. brasiliensis on various growth media, it appears that Scirrhia could represent a genus of more obligate plant pathogens within Mycosphaerellaceae.