16 Sexual Development in Fungi

Sexual development is the process that allows species to reproduce with the potential of generating genetically recombinant progeny. In fungi, sexual reproduction is sustained by a large diversity of developmental processes, which include different mating strategies both at the level of genetic determination and structural organization, as well as diverse morphogenetic systems exhibiting complex temporal and developmental regulation. Sexual reproduction involves the succession of a number of developmental events, which include the differentiation of mating structures, the recognition and attraction of mating partners, and the subsequent alternation of haploid and diploid phases sustained by the progression of plasmogamy, karyogamy, and meiosis. Different temporal organization between these processes can generate distinct genetic constitutions and recombinant genotypes throughout the life cycle of a fungus, as well as amplify the genetic exchange resulting from a single mating event. Sexual reproduction in fungi is often associated to the differentiation of complex multicellular structures, and the progression through the sexual stages requires precise coordination with the differentiation of multiple cell types. In addition, sexual development is also a major process where genome integrity is scrutinized and preserved. The fundamental processes governing sexual development in fungi are now significantly understood at the cellular and molecular level, and increasing comparative analyses among different fungal lineages have started to expose some essential differences in the orchestration of their developmental processes, which account for the diversity of sexual reproductive strategies that have evolved in fungi.