Polyploidy increases storage but decreases structural stability in Arabidopsis thaliana

Whole-genome duplication, leading to polyploidy and endopolyploidy, is widespread throughout the tree of life.1-3 Both polyploidy and endopolyploidy can increase cell size via nucleotypic effects, but the phenotypic consequences of increased cell size at the tissue and whole-organism levels are less well understood.1-4 We quantified the consequences of autopolyploidy and endopolyploidy in nine diploid accessions of Arabidopsis thaliana, representing a gradient in endopolyploidy, to their corresponding experimentally synthesized neo-tetraploid and neo-octoploid cytotypes. The increase in cell size following genome duplication increased plant storage capacity, which increased tolerance of resource limitation, but also incurred biomechanical costs because of a reduction in the amount of cell wall per unit tissue volume. Our findings also show that the functional consequences of autopolyploidy can vary with accession identity, and the presence of this variation suggests that there is potential for adaptation following whole-genome duplication.