Selection of Key Genes for Apricot Kernel Oil Synthesis Based on Transcriptome Analysis.

The purpose of this study was to identify the key genes regulating apricot kernel oil (AKO) biosynthesis and understand the molecular pathways of AKO synthesis and accumulation. This study used two varieties of apricot kernel to determine the oil contents and primary fatty acid compositions at different developmental stages. Candidate genes for AKO biosynthesis were selected through transcriptome sequencing technology and weighted gene co-expression network analysis (WGCNA), and these genes were verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The results indicate that during apricot ripening, the content of AKO exhibits an 'S'-shaped accumulation pattern. The primary fatty acid components are C18:1 and C18:2. The transcriptome sequencing produced 164.19 Gb of clean data and 17,411 differentially expressed genes. The WGCNA results indicate that significantly differentially expressed genes cluster into seven modules-gene clusters (module)-with the strongest correlations to AKO indicated in pink. Nineteen candidate genes were selected from the oil synthesis pathway and WGCNA results. The qRT-PCR results indicate that six key enzyme genes and three transcription factors play significant regulatory roles in AKO biosynthesis. This study elucidates the molecular pathways involved in AKO biosynthesis and explains the difference in oil content between bitter and sweet apricot kernels.