Abstract Detail

Mycological Section

Jenkinson, Thomas [1], Toledo, Felipe [2], Zamudio, Kelly [3], Longcore, Joyce [4], James, Timothy [1].

Population structure of the amphibian-killing chytrid in Brazil is composed of both stable endemic and recently expanded lineages.

Chytridiomycosis of amphibians, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is the emerging infectious disease implicated in the recent population declines and extinction of amphibian species worldwide. Bd strains from regions of disease-mediated amphibian decline consistently belong to a single, hypervirulent clonal genotype (Bd-GPL). Recently however, multiple groups have reported the existence of novel Bd genotypes, including the existence of a hybrid genotype and a distinct local lineage from the Atlantic rainforest of southeastern Brazil (Bd-Brazil). We build on this prior work to define the spatial distribution of this newly discovered genetic variation, and determine the population history of novel and hybrid genotypes in the Brazilian Atlantic Forest. To investigate the genetic structure of novel, pandemic and hybrid lineages in this putative hybrid zone, pure isolates of pathogen strains were collected from Bd infected amphibians at ten field sites along a 2400 km transect of the historical range of the Atlantic rainforest. Isolates of Bd strains were genotyped by multilocus sequence typing with newly developed markers to assess the spatial distribution and structure of Bd genotypes. Bd-Brazil and hybrid strains show restricted distributions in the Atlantic Forest, while Bd-GPL strains are widespread and geographically unstructured. We provide evidence that newly discovered Brazilian lineages are endemic to the Atlantic Forest of Brazil and that Bd-GPL is likely a recently expanded invasive. We followed up on the population genetic study by Illumina sequencing select Brazilian isolated strains to assess lineage ages, and the organization of diversity in the genome. Preliminary results support the hypothesis of long term endemism of Bd-Brazil, and suggest that aneuploidy changes and copy number variation are important factors in the genomic evolution of Bd.

1 - University of Michigan, Ecology and Evolutionary Biology, 830 North University Avenue, Rm 2019, Ann Arbor, MI, 48109, USA
2 - University of Campinas (UNICAMP), Animal Biology, Rua Monteiro Lobato 255, Campinas, SP, 13083-862, Brazil
3 - Cornell University, Ecology and Evolutionary Biology, E206/217 Corson Hall , Ithaca, NY, 14853, USA
4 - University of Maine, School of Biology and Ecology, 5722 Deering Hall, Orono, ME, 04469, USA

Keywords:
Chytridiomycota
population genetics
Emerging Infectious Disease
pathogens.

Presentation Type: Oral Paper:Papers for Sections
Session: 67
Location: Salon 1/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 1:30 PM
Number: 67001
Abstract ID:1254
Candidate for Awards:None