Abstract
The Arabidopsis thaliana population has been exposed to unexperienced
biotic and abiotic stresses as a result of range expansion or
environmental change. To obtain a global picture of the genetic
adaptations in the population history of A. thaliana, we constructed a
database of the phenotypic-adaptations (p-adaptations) and gene
expression-adaptations (e-adaptations). We analysed the dynamics of the
allele frequencies at the 23,880 QTLs of 174 traits and 8,618 eQTLs of
1,829 genes with respect to the total SNPs in the genomes, and
identified 650 p-adaptations and 3,925 e-adaptations (FDR=0.05). The
population underwent large scale p-adaptations and e-adaptations along
four lineages, the eastward migration to Central Asia and South Siberia,
Russia, the northward migration to Sweden, the migration to Azerbaijan,
and the migration of the German population to the United States.
Extremely cold winters and short summers prolonged seed dormancy, and
expanded the root system architecture. Low temperatures prolonged the
growing season and low light intensity required the increased
chloroplast activity. The subtropical and humid environment enhanced
phytohormone signaling pathways in response to the biotic and abiotic
stresses. Exposure to heavy metals selected for alleles underlying low
heavy metal uptake from soil, lower growth rate, lower resistance to
bacteria, and higher expression of photosynthetic genes were selected.
The database of p-adaptations and e-adaptations, which complements
studies focusing on specific aspects of adaptation, may be useful for
future studies to understand the biological adaptations of A. thaliana
throughout its population history.