A new alkali-tolerant ascomycete Heleococcum alkalinum life history
2005
Kozlova, M.V.(Moscow State Univ. (Russian Federation). Faculty of Biology. Dept. of Mycology and Algology) | Bilanenko, E.N.(Moscow State Univ. (Russian Federation). Faculty of Biology. Dept. of Mycology and Algology)E-mail:[email protected]
A new ascomycete was isolated from saline soda soils (pH 10-11) of Central Asia and Africa. It is described as Heleococcurum alkalinum Bilanenko et Ivanova (Hypocreales) (Bilanenko et al., 2005). Here we present the results of a detailed ontogenetic study of H. alkalinum. The morphology and cytology of the species were studied and its life cycle was reconstructed. All the strains studied were found to be primary homothallic. Upon formation of coiled ascogonia, the monoconidial cultures produced dark brown cleistothecial ascomata with multilayered peridium and several asci, which are tightly packed in the ascocarp centrum. The ascus wall was found to diasappear long before ascospore maturation. Thus a syncytium in which developing ascospores are embedded is formed in the ascocarp centrum. The syncytium autolyses with time coming slime in which ascospores reveal. Mature ascospores are brown, thick-walled, smooth and not constricted at the septum, bicellular with one nucleus in each cell. The sterile elements and some cells though to be meristematic were also observed in the ascocarp centrum. This factor proves that H. alkalinum may be placed in Hypocreales although it is characterized by cleistothecial ascomata in contrast to majority of hypocrealen fungi. The species has an anamorph placed in Acremonium sect. Nectrioidea with conidiophores, varying from simple to branched and uninucleate phialoconidia.
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