mRNA library of Oncidium root symbiosed with P. indica
Total RNA was isolated from control roots and those colonized with P. indica using the pine tree method. The RNA integrity number (RIN) was examined on Agilent 2100; when the RIN was > 8.0, the samples were sent to BGI (Shengzheng China) for small RNA Solexa sequencing. In brief: the small molecule RNAs were separated by 15% (w/v) PAGE (18–30 nt), subsequently, the purified small RNAs were ligated to a pair of Solexa adaptors to the 5’ and 3’ ends, reverse transcribed to cDNA using a RT primer, and finally amplified by PCR and sequenced.