title: Coevolution between a family of parasite virulence effectors and a class of LINE-1 retrotransposons.
abstract: Parasites are able to evolve rapidly and overcome host defense mechanisms, but the molecular basis of this adaptation is poorly understood. Powdery mildew fungi (Erysiphales, Ascomycota) are obligate biotrophic parasites infecting nearly 10,000 plant genera. They obtain their nutrients from host plants through specialized feeding structures known as haustoria. We previously identified the AVR(k1) powdery mildew-specific gene family encoding effectors that contribute to the successful establishment of haustoria. Here, we report the extensive proliferation of the AVR(k1) gene family throughout the genome of B. graminis, with sequences diverging in formae speciales adapted to infect different hosts. Also, importantly, we have discovered that the effectors have coevolved with a particular family of LINE-1 retrotransposons, named TE1a. The coevolution of these two entities indicates a mutual benefit to the association, which could ultimately contribute to parasite adaptation and success. We propose that the association would benefit 1) the powdery mildew fungus, by providing a mechanism for amplifying and diversifying effectors and 2) the associated retrotransposons, by providing a basis for their maintenance through selection in the fungal genome.
authors.affiliation: Department of Disease and Stress Biology, John Innes Centre, Norwich, United Kingdom. soledad.sacristan@upm.es
authors.forename: Soledad
authors.initials: S
authors.lastname: Sacristán
authors.forename: Marielle
authors.initials: M
authors.lastname: Vigouroux
authors.forename: Carsten
authors.initials: C
authors.lastname: Pedersen
authors.forename: Pari
authors.initials: P
authors.lastname: Skamnioti
authors.forename: Hans
authors.initials: H
authors.lastname: Thordal-Christensen
authors.forename: Cristina
authors.initials: C
authors.lastname: Micali
authors.forename: James K M
authors.initials: JK
authors.lastname: Brown
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ridout
mesh_terms: D001203:Ascomycota / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology; D019143:Evolution, Molecular; D005658:Fungi / Q000235:genetics / Q000378:metabolism; D015723:Gene Library; D005800:Genes, Fungal; D016681:Genome, Fungal; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D008957:Models, Genetic; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D010944:Plants / Q000382:microbiology*; D018626:Retroelements / Q000235:genetics*; D014774:Virulence
chemical_list: D018626:Retroelements