Wednesday, April 17, 2013

On the trail of the amphibian chytrid fungus in the Atlantic Forests of Brazil

by guest blogger, Professor Timothy James
University of Michigan Herbarium

This January to March I traveled to Brazil to work on a few projects and to develop international collaborations.  All of these projects involve aquatic or zoosporic fungi.  One important fungus in particular is the disease agent of amphibian chytridiomycosis (Batrachochytrium dendrobatidis). Try to say that fast four times.  One major goal of the trip was to develop an international collaboration with Brazilian scientists.  The funds for the trip came from a joint program funded by the National Science Foundation and the Fundação de Amparo à Pesquisa do Estado de São Paulo (Foundation for Research Support of the State of São Paulo, or FAPESP).  Our primary collaborators for the project are L. Felipe Toledo and Domingos Leite at the Universidade de Campinas (UNICAMP). Besides having a meeting with folks from southern Brazil interested in amphibian disease, we (myself and two graduate students from U. Michigan, Clarisse Betancourt and Thomas Jenkinson) spent a lot of time hunting frogs and trying to isolate the chytrid fungus. We visited localities in these four states: São Paulo, Paraná, Rio de Janeiro, and Santa Catarina. We found chytrid infected tadpoles at each of the localities. The rate of chytrid infection was really high, roughly the 50% previously reported for Brazilian Atlantic Forest tadpoles (Toledo et al. 2006, South American Journal of Herpetology 1:185). This blew me away as we find almost zero percent tadpoles with dekeratinized mouthparts back in Michigan.

Picture of a Phyllomedusa being swabbed.  Swabs are tested in the lab using DNA methods to determine if the fungus pathogen is present.

After leaving Campinas, I moved to São Paulo to visit the lab of Carmen Pires-Zottarelli at the Instituto de Bôtanica.  The place is a holy land of botanical research in the best way.  It’s situated in green oasis right in the middle of the city and has the city’s public garden attached.  There’s at least six faculty doing mycological research there, including lichenologists and agaricologists, and my host lab which studies aquatic fungi.  We were working on molecular phylogenetics of chytrids and oomycetes.  One project involves documenting zoosporic fungi from Ilha do Cardoso, the most pristine habitat I saw while in Brazil.  

Ilha do Cardoso has forest that is dense with bromeliads, which makes great habitat for amphibians as well.  I don’t think any chytridiomycosis surveys have been done here.
Combining toadstools and toads was never something I’d imagined doing when I entered into the world of mycology.  But, since 1998 we’ve been experiencing a global pandemic of this fungus disease.  More research is needed to understand the disease’s origins and to help with amphibian conservation.  There’s no better place to do that than the Atlantic Forest of Brazil, which has over 500 endemic species of amphibians.

Hygrocybe c.f. conica mushrooms and the pumpkin toadlet Brachycephalus ephippium.


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