Update 22/08/2024: Due to technical disruption, we are experiencing some delays to publication. We are working to restore services and apologise for the inconvenience. For further updates please visit our website
Most fungal mycelia contain haploid nuclei. This is a characteristic of Kingdom Fungi; unlike the other major eukaryotic groups, most true fungi are haploid. Even in fungus-like organisms in the Oomycota (Kingdom Chromista) like Phytophthora infestans, the cause of potato blight, the nuclei are diploid. This difference in ploidy is an important contrast between ‘true’ and ‘non-true’ fungi. Of course, there are exceptions to every rule and some true fungi are diploid, like Candida albicans, a yeast which causes disease in humans; and rhizomorphs and fruit bodies of Armillaria mellea (a pathogen of trees that belongs to the Basidiomycota) (Peabody et al.,2000).
In this chapter compatibility and the individualistic mycelium will be our main concerns. Formation and breakdown of heterokaryons and the nature and maintenance of the dikaryon are major topics, as are the mechanisms that regulate these processes: vegetative compatibility and the incompatibility systems. We also discuss gene segregation during the mitotic division cycle, which culminates conceptually in what is known as the parasexual cycle. Finally, we consider the segregations of the cytoplasmic genetic entities, mitochondria, plasmids, viruses and prions.
Compatibility and the individualistic mycelium
Because of the difference in ploidy, the life cycles of true fungi and those of other major groups of eukaryotes differ significantly. For example, for most true fungi diploid nuclei are only produced transiently during sexual reproduction, whereas the haploid state is limited to the gametes in most animals and plants.
Review the options below to login to check your access.
Log in with your Cambridge Higher Education account to check access.
There are no purchase options available for this title.
If you believe you should have access to this content, please contact your institutional librarian or consult our FAQ page for further information about accessing our content.