ChIRP-seq of Malus domestica:Malus baccata
After 24 h of Fe-deficiency treatment, the roots of Md/Mb grafted seedlings were collected. The roots were then used in ChIRP assays, which were conducted using a ChIRP Kit (BersinBio, Bes5104-3) following the manufacturers instructions. First, 1 g of root tissue was treated with 1% formaldehyde to crosslink proteinRNADNA complexes. Samples were then ground and sonicated to shear the DNA. Chromatin was separated using streptavidin magnetic beads with biotin probes. Then, the enriched DNA sequences were used to construct sequencing libraries, quantified on Agilent 2200 Bio-analyzer, and sequenced on an Illumina Nextseq 500.