Use of transcriptomic profiling to identify candidate genes involved in Polyporus umbellatus sclerotial formation affected by oxalic acid

Abstract

Polyporus umbellatus is a precious medicinal fungus. Oxalic acid was observed to affect sclerotial formation and sclerotia possessed more medicinal compounds than mycelia. In this study, the transcriptome of P. umbellatus was analysed after the fungus was exposed to various concentrations of oxalic acid. The differentially expressed genes (DEGs) encoding a series of oxidases were upregulated, and reductases were downregulated, in the low-oxalic-acid (Low OA) group compared to the control (No OA) group, while the opposite phenomenon was observed in the high-oxalic-acid (High OA) group. The detection of reactive oxygen species (ROS) in P. umbellatus mycelia was performed visually, and Ca2+ and H2O2 fluxes were measured using non-invasive micro-test technology (NMT). The sclerotial biomass in the Low OA group increased by 66%, however, no sclerotia formed in the High OA group. The ROS fluorescence intensity increased significantly in the Low OA group but decreased considerably in the High OA group. Ca2+ and H2O2 influx significantly increased in the Low OA group, while H2O2 exhibited efflux in the High OA group. A higher level of oxidative stress formed in the Low OA group. Different concentrations of oxalic acid were determined to affect P. umbellatus sclerotial formation in different ways.

Transcriptome Analysis Revealed the Mechanism of Inhibition of Saprophytic Growth of Sparassis latifolia by Excessive Oxalic Acid

“…Many studies in fungi have profiled transcriptional changes in fungal mycelia in response to oxalic acid [ 13 ]. Consistent with our observations, excessive oxalic acid down-regulated the expression level of many genes [ 14 ]. The wood-degradation enzyme system of white and brown rot fungi is crucial for the mycelial growth performance and biological efficiency [ 28 ].…”

“…Transcriptome-based analysis of a wood-rot fungus Abortiporus biennis revealed that the addition of oxalic acid significantly promoted the expression of cellulolytic enzyme genes, but significantly inhibited the expression of lignolytic enzyme genes [ 13 ]. Xing et al used transcriptomic profiling to identify candidate genes involved in sclerotial formation by Polyporus umbellatus in the presence of oxalic acid [ 14 ]. These transcriptome data indicated that RNA-seq is a rapid and high-throughput approach for obtaining comprehensive differentially expressed genes (DEGs) of oxalic-acid-treated edible fungi.…”

PuCRZ1, an C2H2 transcription factor from Polyporus umbellatus, positively regulates mycelium response to osmotic stress

“…The regulatory role of CRZ1 in ganoderic acid biosynthesis has only been investigated in Ganoderma lucidum ( Li and Zhong, 2020 ). Previous studies have reported that environmental factors (oxidation, temperature, medium) affect the formation of P. umbellatus sclerotia ( Xing et al, 2013 , 2015 , 2021 ; Bandara et al, 2015 ). Here, we further investigated the function of the transcription factor CRZ1 in P. umbellatus and whether it is associated with resistance and sclerotia formation like other fungi.…”