Gene, phenotype and function: GLABROUS1 and resistance to herbivory in natural populations of Arabidopsis lyrata

Abstract

The molecular genetic basis of adaptive variation is of fundamental importance for evolutionary dynamics, but is still poorly known. Only in very few cases has the relationship between genetic variation at the molecular level, phenotype and function been established in natural populations. We examined the functional significance and genetic basis of a polymorphism in production of leaf hairs, trichomes, in the perennial herb Arabidopsis lyrata. Earlier studies suggested that trichome production is subject to divergent selection. Here we show that the production of trichomes is correlated with reduced damage from insect herbivores in natural populations, and using statistical methods developed for medical genetics we document an association between loss of trichome production and mutations in the regulatory gene GLABROUS1. Sequence data suggest that independent mutations in this regulatory gene have provided the basis for parallel evolution of reduced resistance to insect herbivores in different populations of A. lyrata and in the closely related Arabidopsis thaliana. The results show that candidate genes identified in model organisms provide a valuable starting point for analysis of the genetic basis of phenotypic variation in natural populations.

Genome-wide effects of postglacial colonization in Arabidopsis lyrata

“…As such, it is a more tractable organism for population genetics and allows addressing evolutionary questions and testing the validity of theoretical models (Riihimäki et al, 2005). For instance, A. lyrata, together with other species of the genus Arabidopsis, is intensively used for the study of self-incompatibility evolution (Mable et al, 2005;Schierup et al, 2006) or the genetic basis of adaptation at different geographic scales (for example, Kärkkäinen et al, 2004;Riihimäki et al, 2005, Kivimäki et al 2007.…”

Population structure and historical biogeography of European Arabidopsis lyrata

“…Regional studies with locally dense sampling indicate that Icelandic and Scandinavian samples maintain extensive intra-population diversity (Jonsell et al, 1995;Gaudeul et al, 2007), and that Scandinavian populations may have not been subject to recent genetic bottlenecks . Furthermore, Kivimäki et al, (2007) showed that northern populations have allelic diversity at the FRIDGA locus that is missing from central European populations. These observations do not readily conform to the expectations of rapid post-glacial population expansion from a central European refugium.…”

“…Arabidopsis lyrata is an outcrossing perennial that shows extensive phenotypic variation and grows in natural habitats that span a large ecological range (Jonsell et al, 1995;Kivimäki et al, 2007;Leinonen et al, 2009;Sandring and Å gren, 2009). Already several local adaptation/ selection studies have been published (Kivimäki et al, 2007;Kuittinen et al, 2007;Leinonen et al, 2009), with special emphasis on studying self-incompatibility evolution Schierup et al, 2006;Mable and Adam, 2007). More of such studies are likely to emerge with the recent availability of the genomic sequence, which makes a comprehensive study of A. lyrata's phylogeographic structure timely.…”

Diversity of Armillaria ostoyae in Scots pine plantations in Poland

“…The molecular genetic basis of adaptive variation is of fundamental importance for evolutionary dynamics, but is still poorly known. Only in very few cases has the relationship between genetic variation at the molecular level, phenotype and function been established in natural populations (Kivimäki et al 2007). …”