Polyploid plants carry multiple ancestral genomes within a single nucleus, a condition that can boost adaptability but also trigger internal genetic conflict. How these distinct genomes avoid regulatory chaos has long remained unclear. This study reveals that polyploid rapeseed achieves transcriptional balance through coordinated genomic and epigenomic convergence between its two subgenomes. By integrating chromatin accessibility, histone modifications, DNA methylation, and gene expression data, the researchers show that regulatory features of homoeologous genes become increasingly similar after polyploidization. This convergence significantly reduces expression divergence between duplicated gene pairs and stabilizes genome-wide transcription. The findings uncover a multilayered regulatory strategy that allows polyploid crops to harmonize competing genomes while preserving adaptability to environmental stress.
Polyploidization—whole-genome duplication following interspecific hybridization—is a major force in plant evolution and crop domestication. While polyploid crops often display superior stress tolerance and agronomic performance, the sudden coexistence of divergent parental genomes can lead to “genome shock,” disrupting gene regulation and threatening genome stability. Previous studies have shown that epigenetic reprogramming accompanies polyploid formation, but how genomic variation and epigenomic remodeling jointly regulate homoeologous gene expression remains poorly understood. In particular, whether distinct subgenomes evolve independently or converge toward coordinated regulation has been unclear. Based on these challenges, there is a need to systematically investigate how genomic and epigenomic interactions maintain transcriptional balance in polyploid plants.
Researchers from Huazhong Agricultural University and collaborating institutes reported in January 2026 that coordinated genomic and epigenomic convergence plays a central role in stabilizing gene expression in allotetraploid rapeseed ( Brassica napus ). Published (DOI: 10.1093/hr/uhaf266) in Horticulture Research , the study compares rapeseed with its two diploid progenitors and shows that regulatory features of duplicated genes become increasingly aligned after polyploidization. By constructing high-resolution epigenomic maps, the team demonstrates how chromatin states and cis-regulatory elements act together to reduce expression divergence between subgenomes.
To dissect regulatory coordination in polyploid genomes, the researchers generated comprehensive multi-omics datasets for rapeseed and its diploid ancestors, including chromatin accessibility (ATAC-seq), four key histone modifications, DNA methylation, and transcriptomes. Comparative analyses of more than 14,000 strictly conserved homoeologous gene pairs revealed extensive epigenomic remodeling following polyploidization. Activating and repressive chromatin marks showed conserved regulatory patterns, yet their distribution increasingly converged between rapeseed subgenomes.
Crucially, homoeologous genes with conserved epigenomic features exhibited significantly lower expression divergence than those with divergent chromatin states, indicating that epigenomic convergence directly contributes to transcriptional balance. The study also uncovered pronounced asymmetry between subgenomes: the subgenome displayed greater epigenomic plasticity and regulatory innovation, while the Cn subgenome maintained higher sequence conservation and epigenetic stability.
Further analyses of cis-regulatory elements showed that transcription factor binding sites also converged between subgenomes, driven by asymmetric genomic variation. Together, these results reveal a multilayered regulatory framework in which genomic structure, chromatin state, and cis-regulatory evolution jointly buffer subgenomic conflict and promote adaptive stability in polyploid rapeseed.
“Polyploid genomes face a fundamental challenge: how to coordinate two divergent regulatory systems without compromising stability,” said the study’s senior author. “Our findings show that rapeseed resolves this challenge through coordinated convergence at both genomic and epigenomic levels.” The authors emphasize that epigenomic plasticity provides a rapid and flexible mechanism for harmonizing gene expression, while underlying genomic conservation anchors long-term stability. This dual strategy, they note, may represent a general principle governing the evolutionary success of polyploid crops.
Understanding how polyploid crops stabilize gene expression has important implications for crop improvement and precision breeding. By revealing how epigenomic convergence buffers regulatory conflict, this study provides a conceptual framework for manipulating chromatin states and cis-regulatory elements to enhance stress resilience and yield in polyploid species. The findings also suggest that targeting epigenetic pathways may offer new strategies to optimize gene expression without altering DNA sequence. More broadly, the work advances our understanding of polyploid genome evolution and lays a theoretical foundation for designing next-generation polyploid crops adapted to changing environments.
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References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhaf266
Funding information
This work was supported by the National Natural Science Foundation of China (32222063 and 32370636 to L.Z., 31930032 to J.S., 32200471 to Z.Q.), the National Key Research and Development Program of China (2023YFF1000700 and 2021YFF1000100 to L.Z.). We thank the bioinformatics computing platform at National Key Laboratory of Crop Genetic Improvement in Huazhong Agricultural University.
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.
Horticulture Research
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Genomic and epigenomic coordination maintains subgenome transcriptional balance in allotetraploid Brassica napus
3-Oct-2025
The authors declare that they have no competing interests.