Genotype-specific changes associated to early synthesis of autotetraploids in wild potato species

Abstract

Polyploidy is an important factor in plant evolution that may trigger drastic genome reorganization and phenotypic differentiation. In the last decade, extensive studies have been carried to understand the consequences of allopolyploidization, where the effects of ploidy change may be confounded by interspecific hybridization. By contrast, less is known on autopolyploidization, which only involves doubling of homologous chromosomes. This study was undertaken to assess leaf anatomical modifications and gene expression changes occurring after doubling the somatic chromosome complement of diploid (2n = 2x = 24) potato species Solanum commersonii Dunal and S. bulbocastanum Dunal. Polyploidization did not induce qualitative changes in leaf structure and, for several leaf traits, anatomic modifications were stochastic. In addition, in both species a diploid superiority was generally observed, suggesting the occurrence of a high-ploidy syndrome. Expression change study was carried out on eight important cell cycle-regulatory genes in plant. It revealed a strong alteration of the expression patterns in the 4x genotypes with respect to the 2x parents. Changes often exceed the twofold, with no consistent trend towards up-or down regulation when comparing 2x vis-à-vis 4x. We discuss the possible relevance of epigenetic changes in controlling the expression of duplicated genes.

Field performance of vegetative form traits of neopolyploids produced by in vitro colchicine treatment in Pyrus communis

“…Autopolyploidization induced either an increase or a decrease in the area of leaf lamina (Aversano et al, 2015). As previously reported, in the present study, the triploid clone '3x − 2' had a decrease of leaf size, this is in conformity with Aversano et al (2015) report that some potato autotetraploids showing a decrease of leaf lamina area than its diploid, suggesting the occurrence of a high-ploidy syndrome.…”

Induction of Synthetic Polyploids and Assessment of Genomic Stability in Lippia alba

“…On the other hand, the new synthetic tetraploids showed similar molecular profile when compared to the mother plant (diploid), corroborating the cytogenetic data. Similar results have been observed in Solanum commersonii Dunal, Solanum bulbocastanum Dunal, and in Citrus limonia (L.) Osbeck (Allario et al, 2011;Aversano et al, 2013Aversano et al, , 2015. The distinctiveness of the triploids and the similarity of the tetraploids comparing with the diploid was also detected by genetic similarity analysis.…”

Sexual Polyploidization inMedicago sativaL.: Impact on the Phenotype, Gene Transcription, and Genome Methylation

“…For several traits our autopolyploids performed better than both their parents and 2x hybrids, suggesting that sexual polyploidization between heterozygous, diverse genotypes resulted in increased heterozygosity of 4x BSP plants, a possible cause of “polyploid heterosis”. By contrast, in maize, tobacco, and potato autopolyploids obtained through somatic doubling, 4x plants did not display a polyploid superiority ( Riddle et al 2010 ; Stupar et al 2007 ; Anssour et al 2009 ; Aversano et al 2015 ). This probably reflects the fact that somatic polyploids have the same alleles as the diploid parents, and thus do not have increased allele interactions that can enhance heterosis.…”