Transcription factor Pofst3 regulates Pleurotus ostreatus development by targeting multiple biological pathways

Pleurotus ostreatus is a popular edible mushroom cultivated worldwide. However, the mechanism of P. ostreatus primordia formation is unclear. Pofst3 is a MHR superfamily transcription factor, which has the function of regulating primordia formation. In this study, the target genes of Pofst3 in P. ostreatus were identified by DAP-Seq approach at the genome level, 1481 peaks were obtained and the Pofst3 binding motif sequence was GARGRVGARGAR. The interaction between transcription factor Pofst3 and this motif was confirmed in vitro and in vivo through electrophoretic mobility shift (EMSA) and yeast one-hybrid screening (Y1H) assays. Among the top 20 GO enrichment results, most were related to transcriptional regulation, and some transcription factor encoding genes, such as HMG-box (gene_5346), MADS-box (gene_86), FOG (gene_6211) and RFX (gene_3496) were obtained. Besides basic metabolism, MAPK signaling pathway, Inositol phosphate metabolism, Glycosylphosphatidylinositol (GPI)-anchor biosynthesis and Pentose phosphate pathway were significantly enriched in the KEGG pathway analysis. The expression levels of randomly selected 11 genes, some transcription factor genes, and genes involved in metabolic pathways in wild and Pofst3 transgenic P. ostreatus strains indicated that target genes likely involved in the development of the P. ostreatus primordia. These results indicated that transcription factor Pofst3 ultimately negatively regulated the development of P. ostreatus primordia very likely through regulating a series of biological pathways.