Simultaneous Analysis of Single-nucleus Transcriptome and Chromatin Accessibility Unveils the Mechanisms of Leaf Cell Development in Arachis hypogaea L.
Authors: Liu Hao , Deng Quanqing , Du Puxuan , Lu Qing , Gangurde Sunil , Xiao Yuan , Hu Dongxiu , Wang Wenyi , Li Haifen , Li Shaoxiong , Liu Haiyan , Huang Lu , Wang Runfeng , Liang Xuanqiang , Varshney Rajeev , Hong Yanbin , Chen Xiaoping 
Published: March 2023

Abstract
Plant cell development is an asynchronous process that is governed by multiple layers of gene regulation. However, the correlation between transcriptome and chromatin regulatory events in an allotetraploid species at the single-cell resolution has not been widely studied. Herein, we employed fluorescence-activated nuclei sorting to isolate single nuclei and simultaneously investigate the transcriptome (snRNA-seq) and chromatin accessibility (snATAC-seq) landscapes in the same leaf single-cell of Arachis hypogaea. A total of 5,930 cells with 10,793 expressed genes were classified into 17 cell-clusters and 5,315 chromatin fragments were enriched to target 26,083 genes in the snATAC-seq landscape. The developmental trajectory revealed a conserved ethylene-AP2 module in leaf cell differentiation and provided novel insight for mesophyll and vascular cell development. Additionally, dual-omics described the epidermal progenitor cell development trajectory, primordium and palisade cells were able to convert into spongy cells, and bundle sheath cells developed earlier than other vascular-cells. Further cell-cycle analysis demonstrated that cytokinin biosynthesis promotes mesophyll cell genome replication and lipid pathway participates in guard cell development. snRNA-seq identified that the AT-hook transcription factor AhAHL11promotes leaf area growth by modulating auxin content, but snATAC-seq identified AhBHLH143 displaying contrasting results by repressing leaf development via the jasmonic acid pathway in ectopically expressed Arabidopsis. Conclusively, our study demonstrates that snRNA-seq combined with snATAC-seq is an effective platform for exploring the association between chromatin regulatory events and transcriptional activity across diverse cell types in peanut leaves. The broad application of this approach will enable significant advances in the functional research of tissue growth and development in plant species.
Plant cell development is an asynchronous process that is governed by multiple layers of gene regulation. However, the correlation between transcriptome and chromatin regulatory events in an allotetraploid species at the single-cell resolution has not been widely studied. Herein, we employed fluorescence-activated nuclei sorting to isolate single nuclei and simultaneously investigate the transcriptome (snRNA-seq) and chromatin accessibility (snATAC-seq) landscapes in the same leaf single-cell of peanut. Totally 5,930 cells with 10,793 expressed genes were classified into 17 cell-clusters and 5,315 chromatin fragments were enriched to target 26,083 genes in the snATAC-seq landscape. Developmental trajectory revealed a conserved ethylene-AP2 module in leaf cell differentiation and provided novel insights for mesophyll and vascular cells development. Further ell-cycle demonstrated that cytokinin promotes mesophyll-cell genome replication and lipid pathway participates in guard cell development. snRNA-seq identified AhAHL11 promotes leaf area growth by modulating auxin content, but snATAC-seq identified AhBHLH143 repressing leaf development via jasmonic acid pathway. Conclusively, snRNA-seq combined with snATAC-seq is an effective platform for exploring the association between chromatin regulatory events and transcriptional activity across diverse cell-types. The broad application of this approach will enable significant advances in the functional research of tissue growth and development in plant species.