Polyploidy or whole genome duplication (WGD) has been suggested as one of the major forces in plant evolution. WGD has been implicated in speciation and biodiversification, providing new genetic combinations in natural populations to favor evolution and increasing organism complexity, which often leads to growth vigor and better adaptation to adverse environments, conferring evolutionary advantages to plants. These advantages have also been incorporated into crop breeding programs. Thus, many tetraploid crops show increased stress tolerance, although the physiological, cellular, and molecular mechanisms underlying these different adaptation abilities are poorly known.
The advantages and inconveniences of being polyploid are analysed and discussed in this review, in which we summarize the latest advances made in Arabidopsis polyploidy, but also in other agronomic plant species.
Chromosome status in the genus Arabidopsis after polyploidization events. A. arenosa and A. thaliana persist as both diploid and autotetraploid. Allopolyploid A. suecica is formed by a single hybridization event between A. thaliana and A. arenosa. Mechanisms leading to autotetraploids and allotetraploids are indicated. Other non-shown genus members also suffer polyploidization. Thus, A. lyrata autotetraploid are also frequent and A. kamchatica is originated from multiple allopolyploidization events between A. halleri and A. lyrata. Figure shows also status of endoreplicated tissues obtained by development-associated endocycles. Endoreplication process not only occurs during the development of A. thaliana, but also in A. suecica and A. arenosa.