Dynamic 3D Chromatin Organization and Epigenetic Regulation of Gene Expression in Peanut Nodules

Research by Chunhai Mai and colleagues from Shanxi Agricultural University, in collaboration with other institutions, has shed new light on the complex interactions between chromatin architecture and gene expression during legume nodulation and nitrogen fixation. By generating a high-resolution 3D genomic map of peanut roots and root nodules, the team identified dynamic changes in genomic organization and gene expression that play a crucial role in nodulation and symbiotic nitrogen fixation. This study highlights the importance of chromatin architecture in shaping gene expression and provides new insights into the mechanisms underlying legume nodulation.

Key Takeaways:

• The research team developed a high-resolution 3D genomic map of peanut roots and root nodules, allowing them to study the dynamic changes in genomic organization and gene expression that occur during nodulation and symbiotic nitrogen fixation.
• The study found that 2.0% of chromosomal regions in nodules transition from a repressive (B) to an active (A) compartment, with significant alterations in topologically associated domains (TADs).
• Peanut nodules show more extensive cis-interactions, with hundreds of differentially expressed genes enriched in symbiotic pathways and nitrate metabolism.
• Assay for transposase-accessible chromatin with high-throughput sequencing identified 25,863 and 14,703 open chromatin regions (OCRs) in roots and nodules, respectively.
• The team revealed dynamic local OCRs (LoOCRs) and histone modifications associated with nodulation-related genes, including an H3K27me3 modification-mediated loop that may regulate the expression of Nodule Inception.
• The study provides new insights into the mechanisms underlying legume nodulation and highlights the importance of chromatin architecture in shaping gene expression.

Statistics:

• 2.0% of chromosomal regions in nodules transition from a repressive (B) to an active (A) compartment.
• 100s of differentially expressed genes are enriched in symbiotic pathways and nitrate metabolism in peanut nodules.
• 25,863 and 14,703 open chromatin regions (OCRs) are identified in roots and nodules, respectively.
• The study finds that chromatin architecture shapes gene expression during legume nodulation and nitrogen fixation.

Sources:

• Journal of Integrative Plant Biology, 2025 (Journal of Integrative Plant Biology, Onlinelibrary.wiley.com/journal/10.1111/(ISSN)1744-7909)
• Chunhai Mai, Shanxi Hou Ji laboratory, College of Agriculture, Shanxi Agricultural University, Jinzhong, 030801, People's Republic of China.
• Lixiang Wang, Suqin He, Bingjie Niu, Gaiya Jia, Tao Yang, Yiwei Xu, Meng Ren, Xiaorui Zhao, Xin Liu, and Zhaosheng Kong.