Title: Evolution of asexual and sexual reproduction systems in a Basidiomycete: Mycena galericulata
Abstract: Sexual reproduction has become the dominant reproductive system throughout many higher organisms. Although asexual reproduction seems to have disappeared where sexual reproduction evolved, in several species both reproduction cycles occur together. Sexual reproduction is widespread in fungi and is the force behind recombination and the rising of new genotypes. Basidiomycetes however, also have the opportunity to reproduce asexually. Within the Basidiomycetes, asexual reproduction is a rather common phenomenon, especially in the genus Mycena. In Mycena galericulata (Scop.) S.F. Gray 1821 both reproduction cycles still seem to exist together within the same species which is expressed in basidiocarps with either 2or 4-spored basidia. However, it remains unclear what the relation is between the two forms of M. galericulata. To get a better understanding of the relation between the two forms, fruiting bodies have been collected in the field, crossings were performed, a growth experiment has been conducted, fluorescence pictures were taken from different strains and sequences have been obtained using the primers ITS, RPB2, EF1α and B36F. The sequences from the ITS locus were analyzed by constructing a phylogenetic tree. Firstly, the results from the field collection show that the ratio in which the 4-spored type occurs increases at the end of the growing season. Secondly, only successful crosses with clamp connections were obtained from 4-spored crossed with other 4-spored strains. Furthermore, the phylogenetic analysis, based on ITS sequences, did not show any difference between the 2and 4spored and suggests that it is still a mixed population. Furthermore, several sequences from the 2spored type showed double peaks. This was found for all four primer combinations which strongly underpins the conclusion that the 2-spored form is heterozygous. The occurrence of heterozygous 2spored is however, for the ITS locus, less common than in the 4-spored form. The other primer combinations do not show this pattern. In addition, 2-spored single spore cultures gave a single signal, while the sequences obtained from the same basidiocarp showed a double signal. Secondary homothallism and diploidy are suggested as possible explanations for these results, both hypotheses however, can be rejected using counter arguments underpinned with results obtained during this research. The relationship between the 2and 4-spored forms of M. galericulata is still not completely understood. More research is needed to truly understand the reproductive systems used by M. galericulata.
Publication Year: 2011
Publication Date: 2011-01-01
Language: en
Type: article
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot