Modulation of polyketide biosynthetic pathway of the endophytic fungus, Anteaglonium sp. FL0768, by copper (II) and anacardic acid

Abstract

In an attempt to explore the biosynthetic potential of endosymbiotic fungi, the secondary metabolite profiles of the endophytic fungus, Anteaglonium sp. FL0768, cultured under a variety of conditions were investigated. In potato dextrose broth (PDB) medium, Anteaglonium sp. FL0768 produced the heptaketides, herbaridine A (1), herbarin (2), 1-hydroxydehydroherbarin (3), scorpinone (4), and the methylated hexaketide 9S,11R-(+)-ascosalitoxin (5). Incorporation of commonly used epigenetic modifiers, 5-azacytidine and suberoylanilide hydroxamic acid, into the PDB culture medium of this fungus had no effect on its secondary metabolite profile. However, the histone acetyl transferase inhibitor, anacardic acid, slightly affected the metabolite profile affording scorpinone (4) as the major metabolite together with 1-hydroxydehydroherbarin (3) and a different methylated hexaketide, ascochitine (6). Intriguingly, incorporaion of Cu2+ into the PDB medium enhanced production of metabolites and drastically affected the biosynthetic pathway resulting in the production of pentaketide dimers, palmarumycin CE4 (7), palmarumycin CP4 (8), and palmarumycin CP1 (9), in addition to ascochitine (6). The structure of the new metabolite 7 was established with the help of spectroscopic data and by MnO2 oxidation to the known pentaketide dimer, palmarumycin CP3 (10). Biosynthetic pathways to some metabolites in Anteaglonium sp. FL0768 are presented and possible effects of AA and Cu2+ on these pathways are discussed.

Phytotoxic Secondary Metabolites from Fungi

“…Ascosalitoxin ( 209 ) was a trisubstituted salicylic aldehyde which belonged to the methylated hexaketide via polyketide biosynthetic pathway [ 165 ]. This metabolite was isolated from Ascochyta pisi var.…”

Antifungal Agents in Agriculture: Friends and Foes of Public Health

“…Endophytic fungi have been studied as an alternative and sustainable means of converting the natural compounds in host plants to antifungal compounds, which are not only effective against human pathogens but also against phytopathogens [127]. Endophytic microorganisms are found in plant species of extreme importance [124] and can be classified as competent, optional, obligatory, opportunistic, or passive, depending on their effects on plants [128][129][130][131]. Recently, they have gained special attention due to the benefits these microorganisms can confer onto their hosts in the form of pesticides, helping the growth and survival of plants and increasing their tolerance to extreme temperatures and drought as well as removing contaminants from the soil [132].…”

Phytotoxic Metabolites Produced by Legume-Associated Ascochyta and Its Related Genera in the Dothideomycetes

“…Stagonosporopsis salicorniae ) and Anteaglonium sp. [26,27]. These diverse fungi producing ascochitine all belong to the order Pleosporales in Dothideomycetes, suggesting ascochitine production is ancestral to the legume-associated Ascochyta and Phoma species.…”