Accession-specific Parent-of-origin Dependent and Independent Genome Dosage Effects on Salt Tolerance in Arabidopsis Thaliana

Improving the salt stress tolerance of crops is an important goal in plant breeding. Changes in the number of chromosome pairs (i.e. ploidy level) cause genome dosage effects which can result in improved traits or emergence of novel traits. The genetic and epigenetic contribution of maternal or paternal chromosomes can differentially affect physiological and metabolic characteristics of F1 offspring. Hence genome dosage effects can be parent-of-origin independent or dependent. The model plant Arabidopsis thaliana displays both genome dosage and parent-of-origin effects on plant growth under normal, non-stress conditions. Using an insogenic ploidy series of diploid, triploid and tetraploid lines we investigate the extent of genome dosage effects and their parent-of-origin dependency on in vitro salt stress tolerance of seedlings across ten different A. thaliana accessions (genetic backgrounds). We demonstrate genome dosage effects on salt stress tolerance in five accessions, and using reciprocal triploid lines demonstrate parent-of-origin dependent genome dosage effects on salt stress tolerance in three accessions. Our results indicate that epigenetic genome dosage and genome dosage balance effects can have significant impacts on abiotic stress tolerance in plants.