Poplar Gene Expression Analysis

First strand cDNA was synthesized from 1.0 μg total RNA digested by DNase I by using the PrimeScript™ RT reagent Kit for RT-PCR (Takara, China), according to the manufacturer's instructions. The specific primers for poplar were synthesized by the Shanghai Sangon biotechnology company (Shanghai, China). qRT-PCR used a SYBR Premix ExTaq™ kit (Takara, China) in an ABI 7500. To quantify the relative expression level of the target genes, the poplar reference gene Actin (GenBank Accession No. AY261523.1/U60491) was used as the internal control. The Actin gene primer pairs were as follow: forward, 5′-CTCCATCATGAAATGCGATG-3′; reverse, 5′-TTGGGGCTAGTGCTGAGATT-3′ (Du et al., 2013a (link)). Three independent biological replicates were performed for each selected gene (two time technical repeats per biological replicate).