Identification of a <i>Ganoderma lucidum</i> Endogenous Reference Gene and Its Validation for Quantitative Analysis of Spore Powders and Fruiting Bodies from Different Land Sources

Background: Ganoderma lucidum (G. lucidum) polysaccharides (GLPs) are believed to be one of the major bioactive components to promote health benefits. The uridine diphosphate glucose pyrophosphorylase (UGPase) genes are key to regulate the synthesis of GLPs. Therefore, this study sought to characterize the UGPase genes and evaluated the GLPs yield from different sources. Methods: The GLPs were extracted by water soaking alcohol precipitation method and contents were calculated by phenol sulfuric acid method. The whole UGPase gene and an internal reference gene were amplified separately, transferred into plasmid vector, cloned, sequencing and bioinformatics analysis. qPCR was performed to determine the mRNA expression of UGPase gene from different G. lucidum sources. Results: The contents of spore powder and fruiting bodies showed that there was a difference among these different products (P &lt; 0.05). The physicochemical properties of UGPase protein showed that the all G. lucidum from spore powder and fruiting body were similar. Moreover, the relative expression of UGPase mRNA in different sources as well as in the same source demonstrated a significant difference (P &lt; 0.05). The relative expression of GLP and UGPase mRNA in spore powder of the same ground source was higher than those in fruiting bodies (P &lt; 0.05). Conclusion: The quantitative detection of GLP contents and expression of UGPase mRNA levels proposed in the study can be used for the evaluation of the G. lucidum quality.