Total RNA from all the tissue samples (Figure S4) was extracted using the Spectrum™ Plant Total RNA Kit (Sigma‐Aldrich, USA) following the manufacturer's instructions. Aliquots of purified RNA were stored at −80 °C. The concentration of RNA was confirmed using Qubit fluorometer with Qubit RNA assay kit (Life Technologies, Australia). The integrity of total RNA was determined by electrophoretic separation on 1.2% (w/v) denaturing agarose gels. Sequencing libraries were constructed using 500 ng of total RNA with a TruSeq® Stranded Total RNA Sample Prep Kits with Ribo‐Zero (Illumina, San‐Diego, USA) following the manufacturer's instructions. Library concentrations were measured using a Qubit fluorometer with Qubit dsDNA BR assay kit (Life Technologies, USA) and Agilent high‐sensitivity DNA chips (Agilent Technologies, USA). The amplified libraries were pooled in equimolar amounts, and quality was assessed with Agilent high‐sensitivity DNA chips (Agilent Technologies, USA). Paired‐end 100‐bp x 2 sequencing was performed with HiSeq2000 (Illumina, San‐Diego, USA).