Instability of chromosome number and DNA methylation variation induced by hybridization and amphidiploid formation between Raphanus sativus L. and Brassica alboglabraBailey

BMC Plant Biology

Research Article

Xiangsong Li¹  Hong Long¹  Yanjie Wang¹  Xuanli Li¹  Lihua Wei¹  Bing Wang¹  Weiwei Guo¹  Jiangsheng Wu²  Honggao Chen² 

[1] College of Life Sciences and Technology, Huazhong Agricultural University, 430070, Wuhan, China;National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070, Wuhan, China;

关键词: Chromosome Number;    Embryo Rescue;    CCGG Site;    Distant Hybridization;    Full Methylation;   

DOI  :  10.1186/1471-2229-10-207

 received in 2009-12-14, accepted in 2010-09-17,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundDistant 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.ResultsF1 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.ConclusionsOur 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.

【 授权许可】

Unknown   
© Li et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.