ABSTRACT
Several fungi produce elaborate structures called conidiophores that bear asexual spores called conidia. These can be quite complex structures resembling a bunch of grapes, a spike of wheat, or a capitulum of dandelion. The conidiophore is a multicellular structure, but the cells are all attached transversely, not laterally. This is because in fungi cell wall is laid down transversely, not vertically. The conidiophore of Aspergillus nidulans (Ascomycotina) is a morphological device that loosely packs a large number of conidia in a small space in a short time and for the continuous dissemination of short-lived conidia by whiff of the wind, splash of rain, or insects. The principles elucidated from this relatively simple system apply to embryonic development, such as in how the embryo marks and measures space and time so that organs and tissues develop on schedule and in the right locations. A special advantage of studying development and differentiation in Aspergillus is that each of its conidia is uninucleate, providing a convenient source of identical haploid cells for UV mutagenesis for the selection of developmental mutants. A. nidulans is expected to prove more useful as a model for the study of fungal development as its genome sequence has been determined.
