International Journal of Molecular Sciences Article Phylogenomic proof of Recurrent Demipolyploidization and Evolutionary Stalling of the “Triploid Bridge” in Arundo (Poaceae) 1,2, 1, 3 1 4 Wuhe Jike y, Mingai Li y, Nicola Zadra , Enrico Barbaro , Gaurav Sablok , Giorgio Bertorelle 2 , Omar Rota-Stabelli 3 and Claudio Varotto 1,* 1 Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all’Adige (TN), Italy;
[email protected] (W.J.);
[email protected] (M.L.);
[email protected] (E.B.) 2 Dipartimento di Scienze della Vita e Biotecnologie, Università degli Studi di Ferrara, 44121 Ferrara, Italy;
[email protected] 3 Department of Sustainable Ecosystems & Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, 38010 San Michele all’Adige (TN), Italy;
[email protected] (N.Z.);
[email protected] (O.R.-S.) 4 Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland; gaurav.sablok@helsinki.fi * Correspondence:
[email protected]; Tel.: +39-0461-615-108 These authors contributed equally to this work. y Received: 2 July 2020; Accepted: 22 July 2020; Published: 24 July 2020 Abstract: Polyploidization is a frequent phenomenon in plants, which entails the increase from one generation to the next by multiples of the haploid number of chromosomes. While tetraploidization is arguably the most common and stable outcome of polyploidization, over evolutionary time triploids often constitute only a transient phase, or a “triploid bridge”, between diploid and tetraploid levels. In this study, we reconstructed in a robust phylogenomic and statistical framework the evolutionary history of polyploidization in Arundo, a small genus from the Poaceae family with promising biomass, bioenergy and phytoremediation species.