AUTHOR=Pan Qi , Zhu Bin , Zhang Dawei , Tong Chaobo , Ge Xianhong , Liu Shengyi , Li Zaiyun 

TITLE=Gene Expression Changes During the Allo-/Deallopolyploidization Process of Brassica napus

JOURNAL=Frontiers in Genetics

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2019.01279

DOI=10.3389/fgene.2019.01279

ISSN=1664-8021

ABSTRACT=<p>Gene expression changes due to allopolyploidization have been extensively studied in plants over the past few decades. Nearly all these studies focused on comparing the changes before and after genome merger. In this study, we used the uniquely restituted <italic>Brassica rapa</italic> (RBR, A<sub>e</sub>A<sub>e</sub>, 2n = 20) obtained from <italic>Brassica napus</italic> (A<sub>n</sub>A<sub>n</sub>C<sub>n</sub>C<sub>n</sub>, 2n = 38) to analyze the gene expression changes and its potential mechanism during the process of allo-/deallopolyploidization. RNA-seq-based transcriptome profiling identified a large number of differentially expressed genes (DEGs) between RBR and natural <italic>B. rapa</italic> (A<sub>r</sub>A<sub>r</sub>), suggesting potential effects of allopolyploidization/domestication of AA component of <italic>B. napus</italic> at the tetrapolyploid level. Meanwhile, it was revealed that up to 20% of gene expressions were immediately altered when compared with those in the A<sub>n</sub>-subgenome. Interestingly, one fifth of these changes are in fact indicative of the recovery of antecedent gene expression alternations occurring since the origin of <italic>B. napus</italic> and showed association with homoeologous expression bias between A<sub>n</sub> and C<sub>n</sub> subgenomes. Enrichment of distinct gene ontology (GO) categories of the above sets of genes further indicated potential functional cooperation of the A<sub>n</sub> and C<sub>n</sub> subgenome of <italic>B. napus</italic>. Whole genome methylation analysis revealed a small number of DEGs were identified in the differentially methylated regions.</p>