Portal de Periódicos da CAPES

THE MATING SYSTEMS OF FUNGI

1963; Wiley; Volume: 62; Issue: 2 Linguagem: Inglês

10.1111/j.1469-8137.1963.tb06328.x

1469-8137

J. H. Burnett, M. EILEEN BOULTER,

Yeasts and Rust Fungi Studies

S ummary Isolations of Mycocaha denudata and M. duriaeana were grown in plate culture and their mating systems studied. The former species is heteromictic and shows both bipolar diaphoromixis and facultative homo‐heteromixis, the latter species is almost certainly homomictic. None of these mating systems have been found before in Nidulariales. It is suggested that the abundance, morphological variation and ecological tolerance of these species may be related to their kinds of mating system. Facultative homo‐heteromixis in M. denudata results in spores being produced in a single peridiolum which are either homocaryotic or heterocaryotic in respect of mating‐type factors. The condition is due to a dominant gene Pd which determines a precocious division of the four nuclei, formed by a normal meiosis, in each basidium. The eight nuclei so formed appear to migrate at random, in respect of the mating‐type factors they carry, into the basidiospores which are each ultimately binucleate. This mechanism is not yet known in other Basidiomycetes. Isolations of M. denudata fell into two groups (I and II) between which there was complete sterility but no other constant distinguishing features could be observed between them. The occurrence of such groups is thought to be of significance in fungi and at present it seems best to regard them as comparable to sibling species. Four mating‐type factors were identified amongst the six isolations of group I, seven amongst the sixteen isolations of group II. Estimates of the total numbers of mating‐type factors in group I and group II are seven to eight and twelve to thirteen respectively. Thus, like other Nidulariales, M. denudata appears to have only a relatively small number of mating‐type factors and the relation of this to inbreeding and dispersal mechanisms is discussed.