library_construction_protocol: Roots and nodules were chopped and passed through a 30µm cell strainer. The filtered nuclei were purified by cell sorting using FACSAria II™ cell sorter (BD Biosciences). An average of 80-100,000 nuclei were collected for each sample, centrifuged, and re-suspended in phosphate buffered saline-bovine serum albumin 0.5%-RNA-inhibitor solution. Libraries were performed according to the manufacturer's instructions (single cell 3' v2 protocol, 10x Genomics).