Nuclei isolation protocol from diverse angiosperm species
The ability to generate intact nuclei is crucial to the success of a variety of genomics experiments, such as Assay for Transposase-Accessible Chromatin using sequencing (ATAC- seq), Cleavage Under Targets and Tagmentation (CUT&Tag), and nuclei-based single cell sequencing (e.g., single nuclei ATAC-seq and single nuclei RNA-seq). For plants, the presence of the cell wall presents significant challenges in the isolation of nuclei from tissues. Here, we report an optimized nuclei isolation protocol that can be adapted for diverse angiosperm species, including maize, soybean, tomato, potato, and wheat, starting from fresh or frozen tissues. Nuclei release is achieved through chopping tissue on ice, where a key parameter affecting nuclei integrity is the concentration of detergent TritonX-100 in the nuclei isolation buffer. The method is simple, quick, and largely centrifugation-free, in which debris is removed by serial filtration. Initial nuclei release and filtration can be performed within 20 min. Fluorescence activated nuclei sorting is then used for final nuclei purification to remove other organelles such as plastids. The protocol uses 500 mg or less plant tissue as input and typically yields at least 100,000 - 200,000 purified nuclei per sample, a common input amount for downstream experiments. Throughout the protocol, we provide guidelines for optimization if performing nuclei isolation from a given species and tissue for the first time.