Phellem tissue from 3y branches
RNA-seq library preparation and sequencing was outsourced.  Total RNAfrom xylem and phellogen tissues was converted to cDNA using theSMART-seq procedure and the paired-end library was prepared followingthe Nextera fragmentation protocol. the sequencing was performed usingthe Ultra-low Sequencing method through Illumina HiSeq 2500 platform.