TY - JOUR

T1 - Evidence for Adaptive Introgression of Disease Resistance Genes Among Closely Related Arabidopsis Species

AU - Bechsgaard, Jesper

AU - Jorgensen, Tove Hedegaard

AU - Schierup, Mikkel Heide

N1 - Copyright © 2017 Bechsgaard et al.

PY - 2017/8/7

Y1 - 2017/8/7

N2 - The generation and maintenance of functional variation in the pathogen defense system of plants is central to the constant evolutionary battle between hosts and parasites. If a species is susceptible to a given pathogen, hybridization and subsequent introgression of a resistance allele from a related species can potentially be an important source of new immunity and is therefore expected to be selected for in a process referred to as adaptive introgression. Here, we survey sequence variation in 10 resistance (R-) genes and compare them with 37 reference genes in natural populations of the two closely related and interfertile species: Arabidopsis lyrata and A. halleri The R-genes are highly polymorphic in both species and show clear signs of trans-species polymorphisms. We show that A. lyrata and A. halleri have had a history of limited introgression for the reference genes. For the R-genes, the introgression rate has been significantly higher than for the reference genes, resulting in fewer fixed differences between species and a higher sharing of identical haplotypes. We conclude that R-genes likely cross the species boundaries at a higher rate than reference genes and therefore also that some of the increased diversity and trans-specific polymorphisms in R-genes is due to adaptive introgression.

AB - The generation and maintenance of functional variation in the pathogen defense system of plants is central to the constant evolutionary battle between hosts and parasites. If a species is susceptible to a given pathogen, hybridization and subsequent introgression of a resistance allele from a related species can potentially be an important source of new immunity and is therefore expected to be selected for in a process referred to as adaptive introgression. Here, we survey sequence variation in 10 resistance (R-) genes and compare them with 37 reference genes in natural populations of the two closely related and interfertile species: Arabidopsis lyrata and A. halleri The R-genes are highly polymorphic in both species and show clear signs of trans-species polymorphisms. We show that A. lyrata and A. halleri have had a history of limited introgression for the reference genes. For the R-genes, the introgression rate has been significantly higher than for the reference genes, resulting in fewer fixed differences between species and a higher sharing of identical haplotypes. We conclude that R-genes likely cross the species boundaries at a higher rate than reference genes and therefore also that some of the increased diversity and trans-specific polymorphisms in R-genes is due to adaptive introgression.

KW - Journal Article

U2 - 10.1534/g3.117.043984

DO - 10.1534/g3.117.043984

M3 - Journal article

C2 - 28630104

VL - 7

SP - 2677

EP - 2683

JO - G3: Genes, Genomes, Genetics (Bethesda)

JF - G3: Genes, Genomes, Genetics (Bethesda)

SN - 2160-1836

IS - 8

ER -