Guyanagaster necrorhizus

Guyanagaster necrorhizus is a gasteromycete, or fungus in the Basidiomycota that cannot forcibly discharge its spores, that is closely related to the root-rotting mushroom-forming genus Armillaria. Guyanagaster is known only from the Pakaraima Mountains in western Guyana. The basidiomes are subhypogeous, entirely enclosed with a thick, durable peridium and have a residual stipe that is usually attached to dead and decaying tree roots. The spores are produced internally within a tough, decay-resistant gleba. The gleba changes color as it matures from white to pink to brick red at maturity. Research on this fungus involves resolving its phylogenetic relationship with the genus Armillaria and determining if it is a pathogen, like Armillaria spp. 

Another research aspect regarding G. necrorhizus is determining how it accomplishes spore dispersal. Field observations have led to the hypothesis it may be utilizing arthropods as its dispersal agent. Two crucial aspects to maintaining a dispersal mutualism are being able to properly 1) attract the dispersal agent and 2) reward the dispersal agent so that they continue to consume and disperse. Yet, how G. necrorhizus accomplishes either of these tasks remain unknown but are the subject of future studies. Research on this remarkable fungus is approached from multiple angles, including field experiments, chemical assays and genomic studies.

 

 

 

 

 Select Publications

 

  • Henkel TW, Smith ME, Aime MC. 2010. Guyanagaster, a new wood-decaying sequestrate genus of Agaricales from the Guiana Shield. American Journal of Botany 97:1474–1484. doi: 10.3732/ajb.1000097

  • Koch RA, Aime MC. 2018. Population structure of Guyanagaster necrorhizus supports termite dispersal for this enigmatic fungus. Molecular Ecology 27: 26672679. doi: 10.111/mec.14710

  • Koch RA, Yoon GM, Aryal UK, Lail K, Amirebrahimi M, LaButti K, Lipzen A, Riley R, Barry K, Henrissat B, Grigoriev I, Herr JR, Aime MC. 2021.  Symbiotic nitrogen-fixation in the reproductive structures of a basidiomycete fungus.  Current Biology 31: 1-10. doi: 10.1016/j.cub.2021.06.033

  • Koch RA, Wilson AW, Sene O, Henkel TW, Aime MC. 2017. Resolved phylogeny and biogeography of the root pathogen Armillaria and its gasteroid relative, Guyanagaster. BMC Evolutionary Biology 17:33. doi: 10.1186/s12862-017-0877-3