Author
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McAlpin, Cesaria |
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Submitted to: Mycologia
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/3/2004 Publication Date: 10/13/2004 Citation: McAlpin, C.E. 2004. Synnema and sclerotium production in aspergillus caelatus and the influence of substrate composition on their development in selected strains. Mycologia. 96(5):937-947. Interpretive Summary: Seed-like structures called sclerotia are produced by many fungi to survive harsh conditions. Knowing how these structures develop may help prevent their formation and therefore, better disease management. The production of synnemata is an important character for identifying species in the Aspergillus group and other fungi. Aspergillus caelatus produces both synnemata and sclerotia with stalk (as well as sclerotia without stalk) which are considered primitive characteristics; the presence of these structures show a link between this fungus and an ancient fungus (Stilbothamnium togoense) found in tropical rainforests. Formation and maturation of the synnemata and sclerotia were greatly affected by the type of media as well as the kind and amount of the carbon and nitrogen sources in the media. Technical Abstract: The ability of Aspergillus caelatus, a new species in Aspergillus section Flavi, to produce synnemata and sclerotia was investigated. Forty eight isolates of A. caelatus differed widely in their production of synnemata and sclerotia; 83% of the isolates produced varying numbers of synnemata and sclerotia and 17% produced neither sclerotia nor synnemata. Most strains produced synnemata and mostly sessile and few stipitate sclerotia on the same Czapek agar (CZA) plate. A. caelatus NRRL 25528 produced more sclerotia than synnemata whereas NRRL 26119 produced abundant synnemata and few sclerotia. The induction and maturation of sclerotia in A. caelatus were greatly affected by the type of media and the kind and concentration of the carbon and nitrogen sources. The irregularly shaped sessile and stipitate sclerotia of A. caelatus resembled structures produced by Stilbothamnium togoense, a tropical fungus recognized for its ability to produce the same types of sclerotia, although at a much reduced size. The production of synnemata and stipitate/sessile sclerotia by several wild type strains of A. caelatus further substantiates previous suggestions for an evolutionary link between the Aspergillus section Flavi and S. togoense. |
