2.1 Chinese walnut sample collection and genomic DNA extraction
We collected leaf samples from a single individual of Chinese walnut (J. cathayensis ) growing in the Qingling Mountains, Xi’an, Shaanxi, China (altitude: 1489 m, 33°46’58”E, 108°34’06”N). Genomic DNA was obtained using a plant DNA extraction Kit (TIANGEN, Beijing, China). A total of 18 tissues were collected from the same tree described above for RNA sequencing (Figure 1a, b; Table S1).