Dynamic Chromatin Accessibility and Gene Expression Regulation During Maize Leaf Development.

Background/objectives: Chromatin accessibility is closely associated with transcriptional regulation during maize () leaf development. However, its precise role in controlling gene expression at different developmental stages remains poorly understood. This study aimed to investigate the dynamics of chromatin accessibility and its influence on genome-wide gene expression during the BBCH_11, BBCH_13, and BBCH_17 stages of maize leaf development.

Methods: Maize leaves were collected at the BBCH_11, BBCH_13, and BBCH_17 developmental stages, and chromatin accessibility was assessed using ATAC-seq. RNA-seq was performed to profile gene expression. Integrated analysis of ATAC-seq and RNA-seq data was conducted to elucidate the relationship between chromatin accessibility and transcriptional regulation.

Results: A total of 46,808, 38,242, and 41,084 accessible chromatin regions (ACRs) were identified at the BBCH_11, BBCH_13, and BBCH_17 stages, respectively, with 23.4%, 12.2%, and 21.9% of these regions located near transcription start sites (TSSs). Integrated analyses revealed that both the number and intensity of ACRs significantly influence gene expression levels. Motif analysis identified key transcription factors associated with leaf development and potential transcriptional repressors among genes, showing divergent regulation patterns in ATAC-seq and RNA-seq datasets.

Conclusions: These findings demonstrate that chromatin accessibility plays a crucial role in regulating the spatial and temporal expression of key genes during maize leaf development by modulating transcription factor binding. This study provides novel insights into the regulatory mechanisms underlying maize leaf development, contributing to a deeper understanding of chromatin-mediated gene expression.