Genome-wide association study reveals new loci involved in Arabidopsis thaliana and Turnip mosaic virus (TuMV) interactions in the field

The genetic architecture of plant response to viruses has often been studied in model nonnatural pathosystems under controlled conditions. There is an urgent need to elucidate the genetic architecture of the response to viruses in a natural setting. A field experiment was performed in each of two years. In total, 317 Arabidopsis thaliana accessions were inoculated with its natural Turnip mosaic virus (TuMV). The accessions were phenotyped for viral accumulation, frequency of infected plants, stem length and symptoms. Genome-wide association mapping was performed. Arabidopsis thaliana exhibits extensive natural variation in its response to TuMV in the field. The underlying genetic architecture reveals a more quantitative picture than in controlled conditions. Ten genomic regions were consistently identified across the two years. RTM3 (Restricted TEV Movement 3) is a major candidate for the response to TuMV in the field. New candidate genes include Dead box helicase 1, a Tim Barrel domain protein and the eukaryotic translation initiation factor eIF3b. To our knowledge, this study is the first to report the genetic architecture of quantitative response of A. thaliana to a naturally occurring virus in a field environment, thereby highlighting relevant candidate genes involved in plant virus interactions in nature.