Evidence for suppression of immunity as a driver for genomic introgressions and host range expansion in races of Albugo candida, a generalist parasite.
How generalist parasites with wide host ranges can evolve is a central question in parasite evolution. Albugo candida is an obligate biotrophic parasite that consists of many physiological races that each specialize on distinct Brassicaceae host species. By analyzing genome sequence assemblies of five isolates, we show they represent three races that are genetically diverged by ∼1%. Despite this divergence, their genomes are mosaic-like, with ∼25% being introgressed from other races. Sequential infection experiments show that infection by adapted races enables subsequent infection of hosts by normally non-infecting races. This facilitates introgression and the exchange of effector repertoires, and may enable the evolution of novel races that can undergo clonal population expansion on new hosts. We discuss recent studies on hybridization in other eukaryotes such as yeast, Heliconius butterflies, Darwin's finches, sunflowers and cichlid fishes, and the implications of introgression for pathogen evolution in an agro-ecological environment.
The Sainsbury Laboratory, Norwich, United Kingdom.
Mark
M
McMullan
The Sainsbury Laboratory, Norwich, United Kingdom.
Anastasia
A
Gardiner
The Sainsbury Laboratory, Norwich, United Kingdom.
Kate
K
Bailey
Max Planck Research Group Fungal Biodiversity, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
Eric
E
Kemen
School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom.
Ben J
BJ
Ward
The Sainsbury Laboratory, Norwich, United Kingdom.
Volkan
V
Cevik
The Sainsbury Laboratory, Norwich, United Kingdom.
Alexandre
A
Robert-Seilaniantz
Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark.
Torsten
http://orcid.org/0000-0001-6759-0074
T
Schultz-Larsen
J.R. Simplot Company, Boise, United States.
Alexi
A
Balmuth
Warwick Crop Centre, University of Warwick, School of Life Sciences, Warwick, United Kingdom.
Eric
E
Holub
School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom.
Cock
C
van Oosterhout
The Sainsbury Laboratory, Norwich, United Kingdom.
Jonathan D G
JD
Jones
D000483:Alleles; D000818:Animals; D018744:DNA, Plant / Q000378:metabolism; D016678:Genome; D058507:Host Specificity; D007109:Immunity; D009711:Nucleotides / Q000235:genetics; D009868:Oomycetes / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity / Q000502:physiology*; D010271:Parasites / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity / Q000502:physiology*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011995:Recombination, Genetic / Q000235:genetics; D016415:Sequence Alignment; D014774:Virulence / Q000235:genetics
D018744:DNA, Plant; D009711:Nucleotides
Albugo candida; arabidopsis; evolutionary biology; genomics; hybridization; introgression; mosaic genome; oomycete; plant biology; recombination