Recent advances of plant polyploidy and polyploid genome evolution

Polyploidization refers to the evolutionary phenomenon that chromosome sets of a species are doubled and which can pass to offspring during the reproductive process. While polyploidy is a ubiquitous feature of all angiosperm plants, its roles in genome evolution and species diversification have been and are still debated. With the advances of DNA sequencing, molecular biology and genomic technologies, significant progress in studies of plant polyploidy and genome evolution has been made during the last decade. In this review, we will follow the research history of plant polyploidy to introduce the classification systems of plant polyploidy as well as the academic debates that are still going on. Then, we summarize recent achievements primarily in major polyploid crops including wheat, rapeseed and cotton, with a special emphasis on the progress of chromosome number and structural variations, genetic and epigenetic modifications as well as gene expression at the mRNA and protein levels. We hope that the summaries and perspectives raised in this review will improve our understanding of the importance of plant polyploidy to species diversification and genome evolution and motivate further studies in this field.