State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China.
State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, China.
Mol Biol Evol. 2021 May 19;38(6):2513-2519. doi: 10.1093/molbev/msab045.
Polyploidization is a major driving force in plant evolution. Allopolyploidization, involving hybridization and genome doubling, can cause extensive transcriptome reprogramming which confers allopolyploids higher evolutionary potential than their diploid progenitors. To date, little is known about the interplay between hybridization and genome doubling in transcriptome reprogramming. Here, we performed genome-wide analyses of transcriptome reprogramming during allopolyploidization in wheat and brassica lineages. Our results indicated that hybridization-induced transcriptional and splicing changes of genes can be largely recovered to parental levels by genome doubling in allopolyploids. As transcriptome reprogramming is an important contributor to heterosis, our finding updates a longstanding theory that heterosis in interspecific hybrids can be permanently fixed through genome doubling. Our results also indicated that much of the transcriptome reprogramming in interspecific hybrids was not caused by the merging of two parental genomes, providing novel insights into the mechanisms underlying both heterosis and hybrid speciation.
多倍化是植物进化的主要驱动力。异源多倍化涉及杂交和基因组加倍，可导致广泛的转录组重编程，使异源多倍体比其二倍体祖先具有更高的进化潜力。迄今为止，人们对杂交和基因组加倍在转录组重编程中的相互作用知之甚少。在这里，我们对小麦和芸薹属植物的异源多倍体化过程中的转录组重编程进行了全基因组分析。我们的结果表明，在异源多倍体中，基因组加倍可以使杂交诱导的基因转录和剪接变化在很大程度上恢复到亲本水平。由于转录组重编程是杂种优势的重要贡献者，我们的发现更新了一个长期存在的理论，即种间杂种的杂种优势可以通过基因组加倍永久固定。我们的结果还表明，种间杂种中的大部分转录组重编程不是由两个亲本基因组的融合引起的，这为杂种优势和杂种物种形成的机制提供了新的见解。
