RNA samples were sequenced using Roche 454 sequencing technology. The main aim was to establish a database for network analysis to determine tissue specific expression patterns. Individual total RNA samples were prepared from bark tissues using the method first described by  and modified by . At least five grams of frozen bark tissues were weighed, ground to a fine powder under liquid nitrogen, and dispersed in CTAB buffer. Following two chloroform extractions, RNA was precipitated with LiCl2, extracted again with chloroform and precipitated with ethanol. The resulting RNA pellet was re-suspended in 40–100 μl of DEPC-treated water, and the quality was assessed with an Agilent Technologies 2100 Bioanalyzer (Agilent Technologies). Poly(A) RNA was purified from total RNA using the Ovation RNA-Seq System kit (NuGen) following supplier’s instructions. Reverse-transcription was performed using the Just cDNA kit (Stratagene) and random hexamer primers.