Engineered Fungus Thermothelomyces thermophilus Producing Plant Storage Proteins

An efficientAgrobacterium-mediated genetic transformation based on the plant binary vector pPZP-RCS2 was carried out for the multiple heterologous protein production in filamentous fungusThermothelomycesthermophilusF-859 (formerlyMyceliophthorathermophilaF-859). The engineered fungusTh.thermophiluswas able to produce plant storage proteins ofZeamays(α-zein Z19) andAmaranthushypochondriacus(albumin A1) to enrich fungal biomass by valuable nutritional proteins and improved amino acid content. The mRNA levels ofz19anda1genes were significantly dependent on their driving promoters: the promoter of tryptophan synthase (PtrpC) was more efficient to expressa1, while the promoter of translation elongation factor (Ptef) provided much higher levels ofz19transcript abundance. In general, the total recombinant proteins and amino acid contents were higher in the Ptef-containing clones. This work describes a new strategy to improve mycoprotein nutritive value by overexpression of plant storage proteins.Keywords:filamentous fungi;Myceliophthorathermophila;mycoprotein;recombinant protein;maize alpha-zein;amaranth albumin A1