Strange Fungi with even stranger insides

Abstract

Since most mycologists work on ascomycetes or basidiomycetes it is easy to forget chytridiomycetes when thinking about fungi, let alone anaerobic chytridiomycetes. So it was hardly surprising that more than one hundred years ago scientists did not recognise the motile spores in a rumen sample as being fungi. Since it was general knowledge that the rumen was infested with bacteria and ciliates the flagellated cells seen by Liebetanz and Braune (1913; 1910) were considered to be flagellates (see Fig 1). About 50 years later there are some careful remarks in the literature about this Callimastix species by Vavra and Joyon (1966) but they do not explicitly mention that it might be a fungus. It took until the seventies before Colin Orpin finally dared to suggest that those strange anaerobic flagellates that live in the rumen might actually be fungi (Munn et al., 1981; Orpin, 1975; 1977). That scientific dogmas are enormous barriers is obvious from the fact that even the great rumen microbiologist Robert Hungate did not believe that fungi could be anaerobic. The late Rudolf Prins told me that in the sixties, when he and Hungate discovered 'fluffy' colonies in anoxic tubes, they always threw them away because oxygen must have seeped in!

Careful examinations by Heath (1983; 1988b) and Barr (1980; 1988) morphologically linked the anaerobic chytrids to the fungi. Modern phylogenetic analyses have confirmed these findings and reveal the chytrid fungi to be the earliest fungal branch (Bowman et al., 1992; Doré and Stahl, 1991; Li and Heath, 1992; Van der Auwera and De Wachter, 1996).