Selection and Validation of Suitable Reference Genes for RT-qPCR Analysis in Bursaphelenchus Xylophilus

Abstract Quantitative reverse transcription polymerase chain reaction (RT-qPCR) is a powerful technique for studying gene expression, and it is widely used in molecular biology and genetic research. The key to quantitative accuracy depends on the stability of the reference genes used for data normalization under different experimental conditions. The pinewood nematode (PWN; Bursaphelenchus xylophilus) is the causal agent of a devastating disease, the pine wood disease (PWD), demanding extensive and prompt research to understand the molecular mechanism of PWD, but the identification of reference PWN genes for standardized RT-qPCR has not been reported yet. In this study, we have analyzed eight candidate reference genes of PWN under different temperature conditions and at different developmental stages. Delta Ct method, GeNorm, NormFinder, BestKeeper and RefFinder algorithms were used to evaluate the expression stability of these genes. 18SrRNA and HIS were selected for gene expression research under temperature treatments, while EF1γ and 18SrRNA for gene expression studies across different developmental stages. In general, the results indicate that 18SrRNA is the most stable gene for RT-qPCR under different conditions. Finally, we use arginine kinase gene (AK) in different temperature and heat shock protein 90 (HSP90) in different developmental stages to confirm the stability of expression. The systematic analysis of qRT-PCR reference gene selection of B. xylophilus will be helpful for future functional analysis and exploration of genetic resources of B. xylophilus.