qPCR-Based Reference Gene Validation in Canarium album: Stability Across Varieties and Developmental Stages

To obtain stable Chinese olive reference genes, eight genes (RPN2B, PIP1.4, NIFS1, RPS16, At5g12110, HSC-2, ABCG44, LOS1) exhibiting stable expression were identified as candidate reference genes from the transcriptome. The expression stability of these genes was evaluated across 33 Chinese olive fruit samples from different varieties and seven developmental stages. The most stable reference genes were determined through comparisons using ΔCq, geNorm, NormFinder, BestKeeper, and RefFinder. Analysis revealed that RPN2B and NIFS1 were consistently ranked among the most stable genes across the different algorithms and exhibited stable expression. Therefore, they are recommended as suitable reference genes for gene expression studies in Chinese olive fruits across different varieties and developmental stages. The four different methods of reference gene stability analysis were used to identify the most stable reference genes in different varieties and developmental stages of Chinese olive fruits, which can be used as a reference for the selection of reference genes in the subsequent gene expression studies of Chinese olive fruits.