Gene-inspired mycosynthesis of skeletally new indole alkaloids.

Dalesindole, an antibacterial and anti-inflammatory indole alkaloid with an undescribed carbon skeleton, was stereoselectively constructed by Daldinia eschscholzii through class II aldolase catalyzed Michael addition of fungal chromone with 3,3'-diindolylmethane (DIM) formed in situ from indole-3-carbinol (I3C) under catalyses of monooxygenase and 8-amino-7-oxononanoate synthase (AONS). Dalesindole isomerizes via a retro-Michael reaction to give stereoisomers with bioactivities. The work provides an access to new bioactive hybrids of fungal oligoketide with microbially decorated exogenous chemistry.