Genomic and transcriptomic alterations following hybridisation and genome doubling in trigenomic allohexaploid Brassica carinata x Brassica rapa
Genomic and transcriptomic alterations following hybridisation and genome doubling in trigenomic allohexaploid Brassica carinata x Brassica rapa
复制标题
三基因组异源六倍体Brassica carinata x Brassica rapa杂交和基因组加倍后的基因组和转录组改变
DOI：
10.1111/j.1438-8677.2011.00553.x
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发表时间：
2012-09-01
期刊：
影响因子：
3.9
通讯作者：
Wang, J.
中科院分区：
文献类型：
--
作者：
Xu, Y.;Zhao, Q.;Wang, J.
异源多倍化是一种重要的进化力量，它涉及两个主要事件：种间杂交和基因组加倍。这两个事件在塑造新异源多倍体的基因组结构中具有重要的功能后果。杂交和基因组加倍对芸苔属异源多倍体基因组和转录组变化的各自影响尚未解决。本研究采用扩增片段长度多态性（AFLP）、甲基化敏感扩增多态性（MSAP）和cDNA-AFLP技术，对异源六倍体芸苔属（ArArArBcBcCcCc基因组）和三倍体芸苔属（ArBcCc基因组）的遗传、表观遗传和转录水平的变化进行了研究。将来自这些组的结果相互比较，并与它们的亲本埃塞俄比亚芥（BBCC基因组）和芜菁（AA基因组）进行比较。在三倍体杂种中检测到快速和显著的遗传、DNA甲基化和基因表达变化。在从三倍体到异源六倍体的转变过程中，一些杂交诱导的改变发生逆转。此外，还检测到新的遗传、表观遗传和转录改变。在三倍体杂种中，A基因组特异性DNA甲基化和基因表达改变的比例显着大于BC基因组特异性改变的比例。然而，在倍性转变期间，两个亲本基因组同样受到影响。杂交诱导的半CCG甲基化变化在基因组加倍后恢复。全CG甲基化变化是一个更普遍的过程，在杂交中开始，并在基因组加倍后继续。这些结果表明，基因组加倍可以改善杂交诱导的基因组和转录组的改变，并在三基因组芸苔属异源六倍体中引发额外的改变。此外，基因组加倍还改变了杂交诱导的祖细胞基因组偏向性改变和表观遗传改变特征。
Allopolyploidisation is a prominent evolutionary force that involves two major events: interspecific hybridisation and genome doubling. Both events have important functional consequences in shaping the genomic architecture of the neo-allopolyploids. The respective effects of hybridisation and genome doubling upon genomic and transcriptomic changes in Brassica allopolyploids are unresolved. In this study, amplified fragment length polymorphism (AFLP), methylation-sensitive amplification polymorphism (MSAP) and cDNA-AFLP approaches were used to track genetic, epigenetic and transcriptional changes in both allohexaploid Brassica (ArArBcBcCcCc genome) and triploid hybrids (ArBcCc genome). Results from these groups were compared with each other and also to their parents Brassica carinata (BBCC genome) and Brassica rapa (AA genome). Rapid and dramatic genetic, DNA methylation and gene expression changes were detected in the triploid hybrids. During the shift from triploidy to allohexaploidy, some of the hybridisation-induced alterations underwent reversion. Additionally, novel genetic, epigenetic and transcriptional alterations were also detected. The proportions of A-genome-specific DNA methylation and gene expression alterations were significantly greater than those of BC-genome-specific alterations in the triploid hybrids. However, the two parental genomes were equally affected during the ploidy shift. Hemi-CCG methylation changes induced by hybridisation were recovered after genome doubling. Full-CG methylation changes were a more general process initiated in the hybrid and continued after genome doubling. These results indicate that genome doubling could ameliorate genomic and transcriptomic alterations induced by hybridisation and instigate additional alterations in trigenomic Brassica allohexaploids. Moreover, genome doubling also modified hybridisation-induced progenitor genome-biased alterations and epigenetic alteration characteristics.