The Key Role of Peltate Glandular Trichomes in Symbiota Comprising Clavicipitaceous Fungi of the Genus Periglandula and Their Host Plants

Abstract

Clavicipitaceous fungi producing ergot alkaloids were recently discovered to be epibiotically associated with peltate glandular trichomes of Ipomoea asarifolia and Turbina corymbosa, dicotyledonous plants of the family Convolvulaceae. Mediators of the close association between fungi and trichomes may be sesquiterpenes, main components in the volatile oil of different convolvulaceous plants. Molecular biological studies and microscopic investigations led to the observation that the trichomes do not only secrete sesquiterpenes and palmitic acid but also seem to absorb ergot alkaloids from the epibiotic fungal species of the genus Periglandula. Thus, the trichomes are likely to have a dual and key function in a metabolic dialogue between fungus and host plant.

Survival and development of potato psyllid (Hemiptera: Triozidae) on Convolvulaceae: effects of a plant-fungus symbiosis (Periglandula)

“…These compounds are produced in grasses by fungal species in the family Clavicipitaceae (genus Epichloё ) which have formed a mutualistic relationship with grasses. A similar mutualistic association between Convolvulaceae and clavicipitaceous fungi in a different genus ( Periglandula ) has been shown to explain the presence of ergot alkaloids in Convolvulaceae [35, 36, 37, 38, 39]. The visual presence of fungal colonies on at least some of our targeted species (Fig 4 AB), combined with extensive literature confirming the presence of ergot alkaloids in Convolvulaceae, prompted us to examine whether psyllid development or lack of development was correlated with the presence or absence of ergot alkaloids.…”

Surface interactions of Fusarium graminearum on barley

“…Non-silicaaccumulating trichomes, characteristic of some dicots, include both 'non-glandular' and 'glandular' trichomes. The latter host a diversity of secondary metabolites and volatiles that have roles in protection from herbivory, fungal infection and abiotic stresses (Hauser, 2014;Horton et al, 2014;Kottb et al, 2015;Mandal et al, 2015;Steiner et al, 2015). To our knowledge, the silicaassociated trichomes of grasses have not been associated previously with plant resistance responses to biotic stress, at least not a cellular response to infection.…”

Ergot Alkaloids and their Hallucinogenic Potential in Morning Glories

“…Highly specialized natural products like ergot alkaloids were not expected to occur in such diverse organisms like fungi (Clavicipi-▶ Table 1 Alkaloid profiles of hallucinogenic Morning Glory plants A. nervosa [10,24], I. violacea [9,10], T. corymbosa [9,10,35,36,44], and I. asarifolia [10,35,36,44]. Isoforms of the alkaloids are not listed.…”

“…Overexpression of the gene leads to an enzyme that exhibits kinetic data in agreement with the function of a 4-(γ,γ-dimethylallyl)tryptophan synthase. Detection of the enzyme by a polyclonal antibody in the hyphae but not in the leaf demonstrates that not only transcription but also translation are processes that are allocated to the clavicipitaceous Periglandula fungus [44].…”

“…2 F). During unfolding of the plant buds and subsequent leaf expansion, the fluorescence fades away [44]. A very minor amount of agroclavine, an early intermediate in ergot alkaloid biosynthesis, was detectable by HPLC/ MS in the fungus [27].…”