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POSTERS: Proteomics/Metabolomics/Genomics II

P-574 - Genome assembly and genetic factors underlying pathogenicity of Mycena citricolor causal agent of the American Leaf Spot in Coffee and multiple hosts.

Tuesday, August 5, 2025
10:15 AM - 11:00 AM HST
Location: Exhibit Hall 3

    Presenting Author(s)

  • CA

    Carlos A. Angel, PhD (he/him/his)

    Scientist & International Consultant. Fmr. Head of Plant Pathology
    Fmr CENICAFE, FNC Plant Pathology - Colombia. Consultant for Ag Aligned Global and IICA.
    Villamaria, Caldas, Colombia

    • Author(s)

  • NL

    Nasmille L. Larke-Mejia

    MSCA postdoctoral fellow at VOLT. , Fmr. Earlham Inst., Norwich UK.
    University of Copenhagen, Dept. of Biology, VOLT Center for Volatile Interactions
    Copenhagen E, Hovedstaden, Denmark

    • Author(s)

  • NA

    Nancy Arciniegas

    Contractor Research Scientist and Consultant
    Fmr CENICAFE, FNC Plant Pathology - Colombia
    Bogota, D.C., Cundinamarca, Colombia

    • Author(s)

  • JD

    José J. De Vega

    Group Leader
    Earlham Institute
    Norwich, England, United Kingdom

Abstract Text: Mycena citricolor, the fungal pathogen responsible for American Leaf Spot (ALS), is a threat to hundreds of hosts and highly important crops such as coffee and avocado, with yield losses ranging from 20% to 90% depending on environmental conditions and limited disease management. Unlike most Mycena species, which are saprophytic or rhizospheric, M. citricolor is the only known pathogenic member of its genus to aerial organs. It follows a hemibiotrophic lifestyle, initiating infection with a brief biotrophic phase before transitioning into a long necrotrophic phase, aided by the secreted toxin oxalic acid, inducing plant tissue damage. To explore genetic factors underlying M. citricolor's pathogenicity, we examined its genome through two assemblies, including a newly generated 77.5 Mb long-read assembly. Comparative analysis with saprophytic Mycena species revealed an expansion of virulence-associated protein families, an enriched secretome, and an increased number of known virulence factor copies. Across both assemblies, we identified over 300 candidate genes, with more than 100 exhibiting strong regulation during plant interactions. Notably, 42 well-characterized virulence factors (MFS1, CUTA, NoxA/B, OLE1, NorA, etc.) were present in multiple copies (3–4 times), alongside several clade-specific uncharacterized genes. These findings suggest that M. citricolor's pathogenicity is driven by genome-wide functional shifts, particularly the expansion of virulence-related genes, and that ALS resistance strategies may align with known plant responses to similar fungal pathogens.