The role of small RNAs in wide hybridisation and allopolyploidisation between Brassica rapa and Brassica nigra.
The role of small RNAs in wide hybridisation and allopolyploidisation between Brassica rapa and Brassica nigra.
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小RNA在白菜和黑芥广泛杂交和异源多倍化中的作用
DOI：
10.1186/s12870-014-0272-9
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发表时间：
2014-10-19
影响因子：
5.3
通讯作者：
Chen L
中科院分区：
文献类型：
--
作者：
Ghani MA;Li J;Rao L;Raza MA;Cao L;Yu N;Zou X;Chen L
背景：异源多倍体的形成包括杂交和染色体加倍两个过程。杂交使不同的基因组在同一细胞中结合，在此过程中发生基因组“休克”和不稳定性，而染色体加倍导致加倍和重建基因组剂量。近年来的研究表明，小分子RNA在维持基因组的重建和稳定中起着重要作用。然而，迄今为止，很少有人知道小RNA在广泛杂交和染色体加倍过程中的作用，这是阐明多倍体形成机制所必需的。结果：异源四倍体与亲本和异源二倍体相比，表现出较高的杂种优势。甲基化敏感性扩增多态性（MSAP）分析表明，异源二倍体的甲基化模式变化比例显著高于异源四倍体，而双亲的DNA甲基化比例高于异源二倍体和异源四倍体。小分子RNA检测结果显示，异源二倍体和异源四倍体中miRNAs的表达量均较亲本增加，siRNAs的表达量较亲本B有增有减。rapa和B.黑，分别。此外，miRNA的百分比随着多倍体水平的增加而增加，但siRNA和DNA甲基化改变的百分比随着多倍体水平的增加而降低。结论：siRNA和DNA甲基化在异源四倍体形成过程中对维持基因组稳定性起重要作用。miRNAs调控基因表达，诱导表型变异，可能在异源四倍体杂种优势的形成中发挥重要作用。本研究结果为阐明异源四倍体比亲本和异源二倍体具有生长优势提供了新的信息。
Background:An allopolyploid formation consists of the two processes of hybridisation and chromosome doubling. Hybridisation makes a different genome combined in the same cell, and genome "shock" and instability occur during this process, whereas chromosome doubling results in doubling and reconstructing the genome dosage. Recent studies have demonstrated that small RNAs, play an important role in maintaining the genome reconstruction and stability. However, to date, little is known regarding the role of small RNAs during the process of wide hybridisation and chromosome doubling, which is essential to elucidate the mechanism of polyploidisation. Therefore, the genetic and DNA methylation alterations and changes in the siRNA and miRNA were assessed during the formation of an allodiploid and its allotetraploid between Brassica rapa and Brassica nigra in the present study.Results:The phenotypic analysis exhibited that the allotetraploid had high heterosis compared with their parents and the allodiploid. The methylation-sensitive amplification polymorphism (MSAP) analysis indicated that the proportion of changes in the methylation pattern of the allodiploid was significantly higher than that found in the allotetraploid, while the DNA methylation ratio was higher in the parents than the allodiploid and allotetraploid. The small RNAs results showed that the expression levels of miRNAs increased in the allodiploid and allotetraploid compared with the parents, and the expression levels of siRNAs increased and decreased compared with the parents B. rapa and B. nigra, respectively. Moreover, the percentages of miRNAs increased with an increase in the polyploidy levels, but the percentages of siRNAs and DNA methylation alterations decreased with an increase in the polyploidy levels. Furthermore, qRT-PCR analysis showed that the expression levels of the target genes were negatively corrected with the expressed miRNAs.Conclusions:The study showed that siRNAs and DNA methylation play an important role in maintaining the genome stability in the formation of an allotetraploid. The miRNAs regulate gene expression and induce the phenotype variation, which may play an important role in the occurrence of heterosis in the allotetraploid. The findings of this study may provide new information for elucidating that the allotetraploids have a growth advantage over the parents and the allodiploids.