*2.2. RNA Extraction and Real-Time Fluorescent Quantitative PCR qRT-PCR Analysis*

Total RNA was extracted using the Trizol method [28]. Synthesis of cDNA was conducted with the PrimeScript™ kit (Takara, Dalian, China) according to the manufacturer's instructions. First, we downloaded the amino acid sequence of *CaHSP18.1a* from the Pepper Genomics Database (accessed date on 1 January 2020, http://peppergenome.snu.ac.kr/: Accession number: CA08g17060). Primer Premier 5.0 was used to design primers, and primer specificity was detected using NCBI Primer BLAST (https://www.ncbi.nlm.nih. gov/tools/primer-blast/, accessed on 5 January 2020) (Supplementary Table S1). The pepper ubiquitin binding gene *CaUbi3* (Accession number AY486137) was used as a reference gene [39]. qRT-PCR was performed using the iQ5.0 Bio-Rad iCycler thermal cycler (Bio-Rad, Hercules, CA, USA). The SYBR Green Super mix (Takara, Dalian, China) was used in the qRT-PCR reaction system following the manufacturer's instructions. The relative expression levels of the gene were analyzed using the 2−ΔΔCT method [40].
