Comparative genomic analyses of the human fungal pathogens Coccidioides and their relatives.
While most Ascomycetes tend to associate principally with plants, the dimorphic fungi Coccidioides immitis and Coccidioides posadasii are primary pathogens of immunocompetent mammals, including humans. Infection results from environmental exposure to Coccidiodies, which is believed to grow as a soil saprophyte in arid deserts. To investigate hypotheses about the life history and evolution of Coccidioides, the genomes of several Onygenales, including C. immitis and C. posadasii; a close, nonpathogenic relative, Uncinocarpus reesii; and a more diverged pathogenic fungus, Histoplasma capsulatum, were sequenced and compared with those of 13 more distantly related Ascomycetes. This analysis identified increases and decreases in gene family size associated with a host/substrate shift from plants to animals in the Onygenales. In addition, comparison among Onygenales genomes revealed evolutionary changes in Coccidioides that may underlie its infectious phenotype, the identification of which may facilitate improved treatment and prevention of coccidioidomycosis. Overall, the results suggest that Coccidioides species are not soil saprophytes, but that they have evolved to remain associated with their dead animal hosts in soil, and that Coccidioides metabolism genes, membrane-related proteins, and putatively antigenic compounds have evolved in response to interaction with an animal host.
Sharpton
Thomas J
TJ
Department of Plant and Microbial Biology, University of California, Berkeley, 94720, USA. sharpton@berkeley.edu
Stajich
Jason E
JE
Rounsley
Steven D
SD
Gardner
Malcolm J
MJ
Wortman
Jennifer R
JR
Jordar
Vinita S
VS
Maiti
Rama
R
Kodira
Chinnappa D
CD
Neafsey
Daniel E
DE
Zeng
Qiandong
Q
Hung
Chiung-Yu
CY
McMahan
Cody
C
Muszewska
Anna
A
Grynberg
Marcin
M
Mandel
M Alejandra
MA
Kellner
Ellen M
EM
Barker
Bridget M
BM
Galgiani
John N
JN
Orbach
Marc J
MJ
Kirkland
Theo N
TN
Cole
Garry T
GT
Henn
Matthew R
MR
Birren
Bruce W
BW
Taylor
John W
JW
D000818:Animals; D003045:Coccidioides / Q000235:genetics*; D049810:Genetic Speciation; D016681:Genome, Fungal; D023281:Genomics / Q000379:methods; D006658:Histoplasma / Q000235:genetics; D006801:Humans; D003904:Mitosporic Fungi / Q000235:genetics*; D008969:Molecular Sequence Data; D020036:Onygenales / Q000235:genetics; D010802:Phylogeny; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA; D026801:Synteny