Instability of chromosome number and DNA methylation variation induced by hybridization and amphidiploid formation between Raphanus sativus L. and Brassica alboglabraBailey
Open Access
- 17 September 2010
- journal article
- Published by Springer Science and Business Media LLC in BMC Plant Biology
- Vol. 10 (1), 207
- https://doi.org/10.1186/1471-2229-10-207
Abstract
Distant hybridization can result genome duplication and allopolyploid formation which may play a significant role in the origin and evolution of many plant species. It is unclear how the two or more divergent genomes coordinate in one nucleus with a single parental cytoplasm within allopolyploids. We used cytological and molecular methods to investigate the genetic and epigenetic instabilities associated with the process of distant hybridization and allopolyploid formation, measuring changes in chromosome number and DNA methylation across multiple generations. F1 plants from intergeneric hybridization between Raphanus sativus L. (2n = 18, RR) and Brassica alboglabra Bailey (2n = 18, CC) were obtained by hand crosses and subsequent embryo rescue. Random amplification of polymorphic DNA (RAPD) markers were used to identify the F1 hybrid plants. The RAPD data indicated that the hybrids produced specific bands similar to those of parents and new bands that were not present in either parent. Chromosome number variation of somatic cells from allotetraploids in the F4 to F10 generations showed that intensive genetic changes occurred in the early generations of distant hybridization, leading to the formation of mixopolyploids with different chromosome numbers. DNA methylation variation was revealed using MSAP (methylation-sensitive amplification polymorphism), which showed that cytosine methylation patterns changed markedly in the process of hybridization and amphidiploid formation. Differences in cytosine methylation levels demonstrated an epigenetic instability of the allopolyploid of Raphanobrassica between the genetically stable and unstable generations. Our results showed that chromosome instability occurred in the early generations of allopolyploidy and then the plants were reverted to largely euploidy in later generations. During this process, DNA methylation changed markedly. These results suggest that, epigenetic mechanisms play an important role in intergeneric distant hybridization, probably by maintaining a genetic balance through the modification of existing genetic materials.Keywords
This publication has 36 references indexed in Scilit:
- Genetic and Epigenetic Mechanisms for Gene Expression and Phenotypic Variation in Plant PolyploidsAnnual Review of Plant Biology, 2007
- Remodeling of DNA Methylation and Phenotypic and Transcriptional Changes in Synthetic Arabidopsis AllotetraploidsPlant Physiology, 2002
- A Sense of SelfTHE PLANT CELL ONLINE, 2001
- Stability and inheritance of methylation states at PstI sites in PisumMolecular Genetics and Genomics, 2001
- Phenotypic Instability and Rapid Gene Silencing in Newly Formed Arabidopsis AllotetraploidsTHE PLANT CELL ONLINE, 2000
- Patterns of cytosine methylation in an elite rice hybrid and its parental lines, detected by a methylation-sensitive amplification polymorphism techniqueMolecular Genetics and Genomics, 1999
- Rapid genomic changes in newly synthesized amphiploids ofTriticumandAegilops. II. Changes in low-copy coding DNA sequencesGenome, 1998
- Rapid genomic changes in newly synthesized amphiploids of Triticum and Aegilops. I. Changes in low-copy noncoding DNA sequencesGenome, 1998
- Differences in DNA methylation patterns are detectable during the dimorphic transition of fungi by amplification of restriction polymorphismsMolecular Genetics and Genomics, 1997
- Polyploid hybrids ofRaphanus sativus L. XBrassica oleracea LMolecular Genetics and Genomics, 1928