title: Genes under positive selection in a model plant pathogenic fungus, Botrytis.
abstract: The rapid evolution of particular genes is essential for the adaptation of pathogens to new hosts and new environments. Powerful methods have been developed for detecting targets of selection in the genome. Here we used divergence data to compare genes among four closely related fungal pathogens adapted to different hosts to elucidate the functions putatively involved in adaptive processes. For this goal, ESTs were sequenced in the specialist fungal pathogens Botrytis tulipae and Botrytis ficariarum, and compared with genome sequences of Botrytis cinerea and Sclerotinia sclerotiorum, responsible for diseases on over 200 plant species. A maximum likelihood-based analysis of 642 predicted orthologs detected 21 genes showing footprints of positive selection. These results were validated by resequencing nine of these genes in additional Botrytis species, showing they have also been rapidly evolving in other related species. Twenty of the 21 genes had not previously been identified as pathogenicity factors in B. cinerea, but some had functions related to plant-fungus interactions. The putative functions were involved in respiratory and energy metabolism, protein and RNA metabolism, signal transduction or virulence, similarly to what was detected in previous studies using the same approach in other pathogens. Mutants of B. cinerea were generated for four of these genes as a first attempt to elucidate their functions.
authors.affiliation: Ecologie, Systématique et Evolution, Université Paris-Sud UMR8079, F-91405 Orsay Cedex, France.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Aguileta
authors.forename: Juliette
authors.initials: J
authors.lastname: Lengelle
authors.forename: Hélène
authors.initials: H
authors.lastname: Chiapello
authors.forename: Tatiana
authors.initials: T
authors.lastname: Giraud
authors.forename: Muriel
authors.initials: M
authors.lastname: Viaud
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Fournier
authors.forename: François
authors.initials: F
authors.lastname: Rodolphe
authors.forename: Sylvain
authors.initials: S
authors.lastname: Marthey
authors.forename: Aurélie
authors.initials: A
authors.lastname: Ducasse
authors.forename: Annie
authors.initials: A
authors.lastname: Gendrault
authors.forename: Julie
authors.initials: J
authors.lastname: Poulain
authors.forename: Patrick
authors.initials: P
authors.lastname: Wincker
authors.forename: Lilian
authors.initials: L
authors.lastname: Gout
mesh_terms: D020171:Botrytis / Q000235:genetics*; D002460:Cell Line; D016000:Cluster Analysis; D003198:Computer Simulation; D019143:Evolution, Molecular; D005800:Genes, Fungal; D016681:Genome, Fungal; D018551:Solanum lycopersicum / Q000382:microbiology; D015203:Reproducibility of Results; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA