No abstract

Pleurotus tuber-regium is a sclerotium-producing mushroom with pharmacological and nutritional value. Many researches applied molecular biological strategies that allow analyzing numerous genes expressed in response to different growth stresses or tissues. In order to capture accurate and reliable results in gene expression studies, it is necessary to select appropriate internal reference genes. They must have relatively uniform expression in the majority of tested samples, thereby reducing the impact of the sample itself on the RT-qPCR results. The selection and validation of 14 candidate reference genes, including α-tub, β-tub, γ-tub, GAPDH, Tif-5a, Tef-1α, ATPase, acyl-CoA, U2ribo, S/G, Wlp, VtpAsE, E3upl, and Sdh, were carried out for gene expression analysis in P. tuber-regium mycelia in response to different temperatures, drought levels, and salinity shifts, fruitbody, and sclerotium. Four statistical algorithms, NormFinder, geNorm, BestKeeper, and RefFinder, were recruited to evaluate the transcription stability of candidate reference genes. The RT-qPCR expression stability analysis indicated that the E3upl and Tif-5a were the most stable expressed genes among all experimental samples, so the combination of these two reference genes is suitable for the analysis of gene expression patterns in P. tuber-regium.

Pleurotus tuber-regium is an edible and medicinal sclerotium-producing mushroom. The sclerotia of this mushroom also serve as food and folk medicine. Based on the description of its monokaryon genome, sequenced with Illumina and PacBio sequencing technologies, comparative transcriptomic analysis using RNA sequencing (RNA-seq) was employed to study its mechanism of sclerotium formation. The de novo assembled genome is 35.82 Mb in size with a N50 scaffold size of 4.29 Mb and encodes 12,173 putative proteins. Expression analysis demonstrated that 1,146 and 1,249 genes were upregulated and downregulated with the formation of sclerotia, respectively. The differentially expressed genes were associated with substrate decomposition, the oxidation-reduction process, cell wall synthesis, and other biological processes in P. tuber-regium. These genomic and transcriptomic resources provide useful information for the mechanism underlying sclerotium formation in P. tuber-regium.