The transcription factor PoMbp1 promotes the growth and development of <i>Pleurotus ostreatus</i> by regulating polysaccharide utilisation

The transcription factor Mbp1 was reported to regulate cell growth and proliferation in some fungi; however, its role in <i>Pleurotus ostreatus</i> remains largely unexplored. Here, we cloned the <i>PoMbp1</i> gene, which encodes a protein contains an APSES domain and is localised in the nucleus. The expression pattern analysis showed that <i>PoMbp1</i> was expressed more in the caps of the fruiting body than in other stages. The growth rates of the <i>PoMbp1</i> overexpression strains OE-<i>PoMbp1</i> were similar to those of wild-type, while that in the interference strains RNAi-<i>PoMbp1</i> were markedly reduced, indicating that <i>PoMbp1</i> positively regulates <i>P. ostreatus</i> development. Transcriptome sequencing showed that the DEGs between <i>PoMbp1</i> transformants and wild-type mainly enriched in carbohydrate metabolism, cell growth and death, etc. The DEGs in polysaccharide catabolic were highly expressed in the OE-<i>PoMbp1</i> strains. Treat <i>PoMbp1</i> transformants with different monosaccharides and polysaccharides, the OE-<i>PoMbp1</i> strains grew faster than wild-type on medium containing polysaccharide, whereas no differences were observed with monosaccharides. The RNAi-<i>PoMbp1</i> strains showed an opposite trend. These results indicated that PoMbp1 plays a positive role in fruit body development by enhancing the expression of genes related to polysaccharide utilisation. This study provides a theoretical reference for research on the mechanism of fruiting body development of <i>P. ostreatus</i>.