Naturally occurring and semisynthetic ergot alkaloids play a role in health care or
as recreational drugs in Western and indigenous Mexican societies. Evidence is summarized
that ergot alkaloids present in Central American Convolvulaceae like Turbina corymbosa, Ipomoea violacea, and Ipomoea asarifolia are colonized by different species of a newly described clavicipitaceous fungal genus
named Periglandula. The fungi are associated with peltate glandular trichomes on the adaxial leaf surface
of its host plants. The Periglandula fungi are not yet culturable in vitro but were demonstrated to have the capacity to synthesize ergot alkaloids. The alkaloids
do not remain in the fungal mycelium but are translocated via the glandular trichomes
into their plant host. Both fungi and host benefit from a symbiotic lifestyle. In
evolutionary terms the alkaloid biosynthetic gene cluster in the Periglandula/Ipomoea symbiosis is likely to have a conserved (basic) structure while biosynthetic ergot
gene clusters within the genera Claviceps and Epichloe were under ecological selection for alkaloid diversification.
Key words
Ipomoea asarifolia
-
Turbina corymbosa
- Convolvulaceae - Clavicipitaceae -
Periglandula
- ergot alkaloids - hallucinogens
