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- Title
SOME BIOCHEMICAL AND ECOLOGICAL ASPECTS OF THE PHYTOPATHOGENIC FUNGUS CLAVICEPS PURPUREA.
- Authors
Andrei, Adrian-Ştefan
- Abstract
Claviceps purpurea is a phytopathogenic fungus that grows on cereals and forage grasses. C. purpurea most commonly infects outcrossing species such as rye (its most common host), as well as triticale, wheat and barley. It rarely infects oats. Three groups within this species (G1, G2 and G3) have been recognized, based on habitat association, sclerotia and conidia morphology, as well as alkaloid production. These groups have been further supported by Random Amplification of Polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers, suggesting that this species may be more accurately described as a species complex. However, all divergent ecotypes can coexist in sympatric populations with no obvious physical barriers to prevent gene-flow. The highly poisonous purple-black sclerotia of the fungus Claviceps purpurea (ergot) and many other Claviceps species are aposematic. Highly toxic fungal sclerotia are associated with conspicuous colours (black, yellow, purple, reddish, brown, violet, white and their combinations) and severely harm herbivores that consume the infected plants, thus meeting the criteria for aposematism. This grass-parasitic ascomycete contains numerous terpenoid indol alkaloids, some of which have dramatic physiological effects and are of great medicinal value. Ergot extracts have long been used in traditional medicine, and several isolated specific alkaloids, as well as semi-synthetic derivates of these, have proved useful remedies in modern medicine. Ergot alkaloid amide and peptide derivatives have a wide variety of physiological effects, including serotonin- and dopamine-receptor agonists and antagonists, vaso-constrictors, neurotoxins and hallucinogens. C. purpurea produces the pharmacologically important ergopeptines, a class of cyclol-structured alkaloid peptides containing D-lysergic acid. These compounds are assembled from D-lysergic acid and three different amino acids by the non-ribosomal peptide synthetase enzymes LPS1 and LPS2. The presence of two distinct NRPS subunits catalyzing formation of ergot peptides is the first example of fungal NRPS system consisting of different NRPS subunits.
- Subjects
CLAVICEPS purpurea; GRAIN; TRITICALE; SCLEROTIUM (Mycelium); CONIDIA; RAPD technique; ERGOT alkaloids
- Publication
Contributii Botanice, 2010, Vol 45, p87
- ISSN
0069-9616
- Publication type
Article