title: GSM9232717: 23366-08_ATAC; Hordeum vulgare; ATAC-seq
library_construction_protocol: Nuclei were prepared by REquest Genomics (Athens, GA, USA). Barley tissue was chopped on ice using a razor blade for ~2 minutes in 600 μL of pre-chilled Nuclei Isolation Buffer (NIB) [https://doi.org/10.1186/1746-4811-9-31]. The chopped tissue was filtered through a 40-μm cell strainer and then subjected to centrifugation at 500 rcf for 5 minutes at 4C. The supernatant was removed and the pellet was resuspended in 500 μL of NIB. The sample was filtered again using a 20-μm cell strainer and then loaded onto the surface of 1 mL of a 35% Percoll buffer, prepared by mixing 35% Percoll with 65% NIB wash buffer. The nuclei centrifuged at 500 rcf for 10 minutes at 4C. The supernatant was carefully removed, and the pellets were washed in 100 μL of 1X TAPS buffer (5X TAPS buffer:  50mM TAPS-NaOH, pH8.0; 25mM MgCl2) [https://doi.org/10.1093/nar/gkw1179]. ATAC-seq libraries were prepared by REquest Genomics (Athens, GA, USA). Nuclei were reconstituted in 30 μL of 2.5X TAPS buffer. A total of 5 μL of nuclei were diluted tenfold and stained with DAPI (Sigma Cat. D9542) to evaluate the quality and abundance using a hemocytometer. A total of 50,000 nuclei were use for library preparation. The Tn5 assembly and library preparation procedures were conducted following previously established methods [https://doi.org/10.1093/nar/gkw1179].