qRT-PCR
To determine the relative transcript levels of selected genes, qRT-PCR was performed with specific primers (Table S1) according to the manufacturer’s instructions for the BIO-RAD Real-time PCR system (Foster City, CA, USA) and the SYBR Premix Ex Taq II system (TaKaRa). Total RNA preparation and real-time RT-PCR were carried out following procedures described in our previous studies (Cai et al., 2015; F. Dang et al., 2013; Zhang et al., 2015). Total RNA was isolated from the pepper samples using TRIzol Reagent according to manufacturer’s protocol (Invitrogen, Canada). The mRNA was reverse-transcribed into cDNA using the reverse transcription system (Takara Biotechnology, Japan). Four replicates of each treatment were performed. Data were analyzed by the Livak method (Livak & Schmittgen, 2001) and expressed as a normalized relative expression level (2-ΔΔCT) of the respective genes. The relative transcript level of each sample was normalized toCaActin (GQ339766) and 18S ribosomal RNA (EF564281), respectively.