Genetics of local adaptation in the laboratory

Abstract

Flowering time in Arabidopsis thaliana is controlled by a large number of genes and various environmental factors, such as light and temperature. The objective of this study was to identify flowering time quantitative trait loci (QTL) under growth conditions simulating seasonal conditions from native geographic locations. Our growth chambers were set to simulate the sprinq conditions in Spain and Sweden, with appropriate changes in light color, intensity and day length, as well as temperature and relative humidity. Thus the Sweden-like spring conditions changed more dramatically compared to Spain-like spring conditions across the duration of our experiment. We have used these conditions to map QTL responsible for flowering time in the Kas-1/Col-g/ 1 recombinant inbred lines (RILs) across two replicate blocks. A linkage map from RILs was established using 119 markets including 64 new SNPs markers. One major QTL, mapping to the FRIGIDA (FRI) locus, was detected on the top of chromosome 4 that showed significant genexseasonal environment interactions. Three other minor QTL also were detected. One QTL mapping near FLOWERING LOCUS M(FLM) showed an epistatic interaction with the QTL at FRI. These QTLxenvironment and QTLxQTL interactions suggest that subtle ecologically relevant changes in light, temperature, and relative humidity are differentially felt by alleles controlling flowering time and may be responsible for adaptation to regional environments. Show more