Major Facilitator Superfamily Transporter Participates in the Formation of Dimeric Sorbicillinoids Pigments.

ABSTRACT

Understanding the biosynthetic pathways of fungal pigments can help elucidate their roles in fungal growth processes. Trichodimerol is a unique cage-like dimeric sorbicillinoids pigment that is commonly isolated from many fungi, however, its biosynthesis is just partially clarified. In this study, we report that a biosynthetic gene cluster encoded major facilitator superfamily transporter (StaE) from the fungus Stagonospora sp. SYSU-MS7888 is involved in the formation of trichodimerol, together with several other dimeric sorbicillinoids. Using Aspergillus oryzae NSARI as a heterologous host, we demonstrated that the formation of dimeric sorbicillinoids required co-expression of the transporter StaE with biosynthetic genes (two PKSs and one monooxygenase) that are responsible for constructing the monomer precursor sorbicillinol. Fluorescence microscopy results showed that eGFP-tagged StaE is localized on the endoplasmic reticulum, suggesting that sorbicillinoid dimerizations might be compartmentalized in this organelle.