远缘杂交诱导的油菜遗传与表观遗传变化

发布时间：2018-06-07 20:25

本文选题：甘蓝型油菜 + 白菜型油菜　；参考：《华中农业大学》2016年博士论文

【摘要】：不同物种的基因组融合导致的异源多倍化过程常常伴随着遗传学和表观遗传学的改变。如将一个亲本的基因组从异源多倍体中分离出来,可较准确的研究异源多倍化所诱导的基因组变化。在本研究中,我们首先利用甘蓝型油菜(Brassica napus,2n=38,AACC)与诸葛菜(Orychophragmus violaceus,2n=24,OO)的体细胞融合产生的异源六倍体(2n=62,AACCOO)与甘蓝型油菜(2n=38,AACC)连续回交所培育出的9个不同附加系,自交所产生的甘蓝型油菜类型后代为材料,通过AFLP、SSAP、MSAP分析,与甘蓝型油菜供体比较,研究结果表明经历多倍化后甘蓝型油菜在基因组成分、转座子活性、DNA甲基化方面都发生了一定程度的;由不同附加系衍生出来的甘蓝型油菜之间的差异很有可能是由于受到了不同的外源染色体的影响。值得指出,那些包含有诸葛菜rRNA显性位点(相对于甘蓝型油菜为显性)的附加系倾向于产生更小的变异,暗示外源rRNA的表达量对基因组的稳定有一定影响。这些结果对理解不同基因组的融合与分离过程中亲本染色体组的遗传改变提供了新的线索。其次,天然甘蓝型油菜经历了长期的进化过程,确切的亲本难以确定,故很难研究祖先基因组的改变。我们利用AFLP、SSAP、MSAP等技术,观察了从甘蓝型油菜中分离出的白菜型油菜(Brassica rapa,2n=20,AA)的基因组组成、转座子活动、DNA甲基化。通过与甘蓝型油菜供体比较,由于C染色体组的丢失,分离出的白菜型油菜显示大量的AFLP片段丢失,但也有大量的新带产生,可能重复杂交所诱导和外源片段渗入。11个A基因组特异的LTR(Copia)反转录转座子表现高频率的SSAP片段丢失和低频率的新带产生。还检测到广泛的甲基化变化。这些结果暗示分离出的白菜型油菜中发生较大范围的遗传学和表观遗传学改变,这些变化可能来源于长期的进化、杂交诱导、外源染色体片段的渗入和其它因素。
[Abstract]:Genetic and epigenetic changes are often associated with heterogeneous polyploidy resulting from genomic fusion of different species. If the genomes of one parent were isolated from the allopolyploids, the genome changes induced by heteroploidy could be studied more accurately. In this study, we first used somatic cell fusion of Brassica napusus 2nC38ACCC and Orychophragmus violaceusus 2nc24OOO) to produce allohexaploid (2nCCOO) and Brassica napusus 2nC38ACCC). Nine different additional lines were obtained by backcrossing continuously with Brassica napusa 2nC38AAACC. in this study, the allohexaploid was obtained from the somatic cell fusion of Orychophragmus violaceusus 2nc24OO) and Brassica napusus 2nCCOO) was used to produce 9 additional lines. The progenies of Brassica napus from self-pollination were analyzed by AFLPS-SSAPP-MSAP and compared with the donors of Brassica napus. The results showed that the genome components of Brassica napus were polyploid. The DNA methylation of transposon actives occurred to a certain extent, and the differences among Brassica napus derived from different additive lines were probably due to the influence of different exogenous chromosomes. It is worth noting that those additional lines containing dominant sites of rRNA in Zhuge (compared with Brassica napus are dominant) tend to produce smaller variations suggesting that the expression of exogenous rRNA may affect the stability of the genome. These results provide a new clue for understanding the genetic changes of parent chromosomes in the process of fusion and separation of different genomes. Secondly, natural Brassica napus has undergone a long period of evolution, the exact parents are difficult to determine, so it is difficult to study the changes of ancestor genome. The genomic composition and DNA methylation of Brassica rapa2ntio 20 (AAA) isolated from Brassica rapa (Brassica rapa) from Brassica napus were studied by AFLP- SSAP- MSAP and other techniques, including DNA methylation of transposon activity in Brassica rapa (Brassica rapa). Compared with the donor of Brassica napus, because of the loss of C chromosome group, the isolated Brassica napus showed a large number of AFLP fragments lost, but a large number of new bands were produced. 11 A genome-specific LTR-Copia) reverse transposons showed high frequency SSAP loss and low frequency new band production. Extensive methylation changes were also detected. These results suggested that a large range of genetic and epigenetic changes occurred in the isolated Brassica campestris. These changes may result from long-term evolution, hybridization induction, the infiltration of exogenous chromosomal fragments and other factors.
【学位授予单位】：华中农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S565.4

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