Transcriptomic Profiling Identifies Candidate Genes Involved in Polyporus Umbellatus Sclerotial Formation Affected by Oxalic Acid

Abstract Polyporus umbellatus is a precious medicinal fungus. The whole transcriptome of P. umbellatus exposed to different concentrations of oxalic acid was performed and analyzed using RNA-seq based on sequencing technology. Reactive oxygen species (ROS) detection of P. umbellatus mycelia was visually conducted and using non-invasive micro-test technology (NMT), the net Ca 2+ and H 2 O 2 fluxes of P. umbellatus were measured. Totally, 22,523 unigenes were generated by De novo assembly of reads and there are 1223 differentially expressed genes (DEGs) between the control group and the high oxalic acid complemented (PD_S) group and 459 DEGs between the control group and the low concentration oxalic acid additive (PU_SM) group. The transcriptomic analysis indicated DEGs encoding enzymes related to oxidative stress, energy metabolism and so on. Compared to that of the control group, the biomass of the sclerotia in the PU_SM group increased 66%, however, no sclerotia formed in the PD_S group. The low concentration of oxalic acid could increase Ca 2+ and H 2 O 2 influx, while the high concentration of oxalic acid presented slight H 2 O 2 efflux. There is a great significant positive correlation between the net Ca 2+ and H 2 O 2 fluxes. Different concentrations of exogenous oxalic acid affected P. umbellatus sclerotial formation in different ways.