Production of Perithecia in Culture byCeratocystis Ulmi

Effect of linoleic acid on reproduction and yeast–mycelium dimorphism in the Dutch elm disease pathogens

“…In this study, we corroborated the effect of linoleic acid on synnemata and perithecia production in DED pathogens observed by Hubbes (1975) and Marshall et al (1982) in complex media (OCM). Based on our observations, no reproductive structures occurred on synthetic medium without elm wood (OMM).…”

“…This would support the involvement of linoleic acid in the production of synnemata, since the latter are found in elm bark beetle breeding galleries under the bark (Hubbes et al 1977). Linoleic acid also favored the production of sexual sporebearing structures (perithecia) in complex media such as agar media containing hot water extracts of American elm wood, American elm leaves, green tea or black tea (Marshall et al 1982).…”

“…Moreover, formation of perithecia in the DED pathogens was triggered by fatty acids in agar media with extracts of American elm wood, American elm leaves, and green and D r a f t black tea, according to Marshall et al (1982). These authors also reported that abundant perithecia were obtained on a medium containing only the extract of black tea, linoleic acid, and pyridoxine.…”

“…Linoleic acid was thus pointed out as the compound that favors formation of reproductive structures. Marshall et al (1982) hypothesized that elm phenolics were also involved in perithecia formation. However, results from an earlier study by Holmes (1970) although numbers were low and inconsistent, as pointed out by Marshall et al (1982).…”

Lipoxygenase inhibitors shift the yeast/mycelium dimorphism in Ceratocystis ulmi

“…Thus, it seems likely that C. ulmi follows the plant-higher fungus lipoxygenase pattern, with linoleic and linolenic acids as substrates, rather than the animal-lower fungus pattern, with arachidonic acid as the substrate. In this regard, plants synthesize jasmonic acid and other hormonelike substances from linolenic acid (33,34), while the importance of PUFAs to C. ulmi has been shown by the observation that on a defined agar medium exogenous linoleic acid causes C. ulmi to produce two reproductive structures (2,20), perithecia (sexual) and synnema (asexual). At least one phytopathogenic fungus, Botryodiplodia theobromae (1,22), is known to produce jasmonic acid.…”