Phenotypic diploidization in plant functional traits uncovered by synthetic neopolyploids.

Whole genome doubling and post-polyploidization genome downsizing play key roles in the evolution of land plants, nevertheless the impact of genomic diploidization on functional traits still remains poorly explored. Using Dianthus broteri as a model, we compared the ecophysiological behaviour of colchicine-induced neotetraploids (4xNeo) to diploids (2x) and naturally occurring tetraploids (4xNat). In order to asses to what extent post-polyploidization evolutionary processes have affected to 4xNat, exhaustive leaf-gas exchange and chlorophyll fluorescence analyses were performed. Genomic diploidization and phenotypic novelty was evident. In addition, the distinct patterns of variation revealed that post-polyploidization processes alter the phenotypic shifts directly-mediated by genome doubling. Photosynthetic phenotype was affected in several ways but a prevalent phenotypic diploidization occurred (i.e., being 2x and 4xNat closer to each other than to 4xNeo). Altogether, our results highlight the potential of considering experimentally synthetized vs. naturally established polyploids when exploring the role of polyploidization on promoting functional divergence.