Abstract Detail

Mycology

Koch, Rachel A. [1], Herr, Joshua R. [2].

Transcriptomics reveals the mycoparasitic strategy of the mushroom Entoloma abortivum on species of the mushroom Armillaria.

During mycoparasitism, a fungusーthe hostーis parasitized by another fungusーthe mycoparasite. The genetic underpinnings of these relationships are best characterized in Ascomycete fungi. However, within Basidiomycete fungi, there are rare instances of mushroom-forming species parasitizing the reproductive structures, or sporocarps, of other mushroom-forming species. One of the most enigmatic of these occurs between Entoloma abortivum and species of Armillaria, where hyphae of E. abortivum disrupts the development of Armillaria sporocarps, resulting in the formation of carpophoroids. However, it remains unknown whether carpophoroids are the direct result of a mycoparasitic relationship. To address the nature of this unique interaction, we analyzed gene expression of field-collected Armillaria and E. abortivum sporocarps and carpophoroids. Transcripts in the carpophoroids are primarily from E. abortivum, supporting the hypothesis that this species is killing Armillaria. Most notably, we identified differentially expressed E. abortivum β-trefoil-type lectins in the carpophoroid, which we hypothesize bind to Armillaria cell wall galactomannoproteins, thereby mediating recognition between the mycoparasite and the host. The most significantly upregulated E. abortivum transcripts in the carpophoroid code for oxalate decarboxylases, enzymes that degrade oxalic acid. Oxalic acid is a virulence factor in many plant pathogens, including Armillaria species, however, E. abortivum has evolved a sophisticated strategy to overcome this defense mechanism. The number of gene models and genes that code for carbohydrate-active enzymes in the E. abortivum transcriptome were reduced compared to other closely related species, perhaps a result of the specialized nature of this interaction.

1 - University of Nebraska-Lincoln, Plant Pathology , Lincoln, NE, 68503, USA
2 - University of Nebraska-Lincoln, Plant Pathology and Center for Plant Science Innovation, Lincoln, NE, 68503, USA

Keywords:
transcriptomics
mycoparasitism
symbiosis
Armillaria
Mycology.

Presentation Type: Oral Paper
Session: MY1, Mycology: Ecology and Conservation
Location: /
Date: Monday, July 19th, 2021
Time: 11:30 AM(EDT)
Number: MY1003
Abstract ID:605
Candidate for Awards:None