Whole genome duplications in plants: an overview from Arabidopsis.

Polyploidy is a common event in plants that involves the acquisition of more than two complete sets of chromosomes. Allopolyploidy originates from interspecies hybrids while autopolyploidy originates from intraspecies whole genome duplication (WGD) events. In spite of inconveniences derived from chromosomic rearrangement during polyploidization, natural plant polyploids species often exhibit improved growth vigour and adaptation to adverse environments, conferring evolutionary advantages. These advantages have also been incorporated into crop breeding programmes. Many tetraploid crops show increased stress tolerance, although the molecular mechanisms underlying these different adaptation abilities are poorly known. Understanding the physiological, cellular, and molecular mechanisms coupled to WGD, in both allo- and autopolyploidy, is a major challenge. Over the last few years, several studies, many of them in Arabidopsis, are shedding light on the basis of genetic, genomic, and epigenomic changes linked to WGD. In this review we summarize and discuss the latest advances made in Arabidopsis polyploidy, but also in other agronomic plant species.