Revelation of the Balanol Biosynthetic Pathway in Tolypocladium ophioglossoides

Abstract

A cryptic gene cluster, bln, was activated by genome mining in Tolypocladium ophioglossoides. This activation led to the production of balanol and eight other metabolites. Gene disruption and metabolite profile analysis showed that the biosynthesis of balanol involved the convergence of independent PKS and NRPS pathways, and a biosynthetic pathway for balanol was proposed.Letter pubs.acs.org/OrgLett

Secondary metabolites from hypocrealean entomopathogenic fungi: genomics as a tool to elucidate the encoded parvome

“…Genome sequence analysis of T. ophioglossoides led to the identification of the BGC for balanol 24 (Scheme 7), a composite PK-NRP metabolite that is a potent ATP-competitive inhibitor of protein kinases C and A. 73 Overexpression of the putative cluster-specific regulator BlnR allowed the expression of the otherwise silent 18-gene BGC, and subsequent deletions of key biosynthetic genes in the BlnRoverexpressing background helped to clarify the biosynthesis of balanol 24. The BGC contains a subcluster organized around the BlnA nrPKS with orthologous genes to that for monodictyphenone biosynthesis from A. nidulans.…”

“…Thus, the balanol BGC is the composite of two semi-independent subclusters that produce a PK and an NRP moiety in a parallel manner, with biosynthesis converging on the BlnN NRPS that fuses the two biosynthons. 1,73 The meroterpenoid immunosuppressants subglutinol A (25, Scheme 8) and subglutinol B were first isolated from Fusarium subglutinans, 75 but these and additional congeners such as compounds 26 and 27 were also obtained from the HEF M. robertsii. 76 Subglutinols feature a PK-derived α-pyrone moiety attached to a terpenoid-derived decalin core fused with a tetrahydrofuran with a prenyl side chain.…”

“…Adapted from Cook et al 71 with permission (Copyright 2017, G3: Genes, Genomes, Genetics). Adapted from He et al 73 with permission (Copyright 2018, American Chemical Society). Adapted from Xia et al 81 with permission (Copyright 2017, Elsevier).…”

Gram-Level Production of Balanol through Regulatory Pathway and Medium Optimization in Herb Fungus Tolypocladium ophioglossoides

“…T. ophioglossoides is a kind of parasitic mushroom of certain Elaphomyces, and it has been used to relieve postmenopausal syndrome in women in Chinese traditional medicine throughout history. Several active compounds have been identified from T. ophioglossoides , such as balanol, cordycepol and tyrosol [ 8 , 9 , 10 ]. Compared with the annotated gene clusters based on the genome sequence of T. ophioglossoides , many other gene clusters are still cryptic during laboratory culture.…”

“…Although balanol has been produced through liquid fermentation, its yield was very low, even in large-scale fermentation. In recent decades, our group focused on the chemical synthesis of balanol, as well as its analogs, before elucidating f its biosynthetic pathway through overexpression of its cluster-situated regulator gene, blnR [ 10 ].…”