2.3. RNA purification
Total RNA was extracted using a modified CTAB method (Chang et al., 1993) from the pooled fruit and pedicel tissues of a Hongro/M9 apple tree sampled in May 2018 (37 DAFB) with four biological replicates. In the next two years, the tree subunit samples consisting of a branch, fruit, and pedicel were collected in time-course during ex-vivoincubation. To extract enough RNA, eight biological replicates were all aggregated and labelled as the same tissue type. The concentration of RNA was measured using BioDrop µLITE spectrophotometer (Cambridge, UK).