Pathogenesis of bryophyte hosts by the ascomycete Atradidymella muscivora

• Author(s) / Creator(s)

  • Tsuneda, A.
  • Davey, M.L.
  • Currah, R.S.

• Atradidymella muscivora (Pleosporales) is a bryophyte pathogen that infects the mosses Aulacomnium palustre , Hylocomium splendens , and Polytrichum juniperinum . Light and scanning electron microscopy and extracellular enzyme production were used to characterize the interactions between this fungus and its native hosts and the model host Funaria hygrometrica. Penetration was direct via hyphae or appressoria, and hosts responded by forming layered, darkly pigmented deposits at penetration sites, similar to the papillae formed by vascular plants in response to fungal infection. Infected hosts gradually became chlorotic as hyphae grew intracellularly, presumably killing host cells. Pycnidia of the Phoma anamorph ( P. muscivora ) and uniloculate pseudothecia were initiated as tightly packed masses of stromatic dematiaceous hyphae within a single host cell. Mature pycnidia and pseudothecia were erumpent. A new microniche among bryophilous fungi is described, whereby A. muscivora supplants the gemmae of Aul. palustre and exploits the normal nutrient-fl ow of the moss gametophyte. Atradidymella muscivora produced both cellulases and soluble polyphenolic oxidases, allowing it to also function as a saprobe and degrade the cell walls of bryophytes. The saprophytic and pathogenic abilities of A. muscivora suggest it may play a role in nutrient cycling, population dynamics, and small-scale disturbances in boreal ecosystems.

• Date created

  2009

• Subjects / Keywords

  • Bryophilous
  • Stroma reduction
  • Microniche
  • Host response
  • Cell wall degradation
  • Papilla
  • Phoma muscivora
  • Pathogenesis

• Type of Item

  Article (Published)

• DOI

  https://doi.org/10.7939/R3VD6PG2J

• License

  This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited.