ABSTRACT
CONTENTS 17.1 Introduction ............................................................................................................................. 279 17.2 Morphology of Sexual Development in Aspergillus nidulans ................................................ 280 17.3 Environmental Factors Affecting Sexual Development ......................................................... 280
17.3.1 Light and VeA ............................................................................................................ 282 17.3.2 Phytochrome Homolog, FphA ................................................................................... 283 17.3.3 Endogenous Inducer-psi Factor ............................................................................... 284 17.3.4 Reactive Oxygen Species and NADPH Oxidase (NoxA) .......................................... 284
17.4 Genes Related in the Mating Process ...................................................................................... 285 17.4.1 Mating-Type Loci (matA and matB) .......................................................................... 285 17.4.2 Putative Pheromone Receptors, GprA and GprB ...................................................... 285
17.5 Signal Transduction Components for Sexual Development .................................................... 286 17.5.1 Putative GPCR, GprD ................................................................................................ 286 17.5.2 MAPKK Kinase, SteC ............................................................................................... 287 17.5.3 MAP Kinase, SakA/HogA ........................................................................................ 288
17.6 Transcription Factors and Regulators Affecting Sexual Development ........................... 288 17.6.1 Positive Sexual Regulator, NsdD ............................................................................... 288 17.6.2 Positive Sexual Regulator, SteA ................................................................................. 291 17.6.3 Transcription Factors Containing Zn(II)2Cys6 Domain, RosA and NosA ................ 291 17.6.4 Development and Amino Acid Availability Control with cpcA and cpcB ................ 292 17.6.5 COP9 Signalosome (CSN) and csnD/E ..................................................................... 293
17.7 Developmental Coordinators and Modifi ers ........................................................................... 293 17.7.1 Spatio-Temporal Coordinators, StuA and MedA ....................................................... 293 17.7.2 Leucine Zipper Protein, DopA ................................................................................... 294 17.7.3 WD Repeat Protein, RcoA ......................................................................................... 294 17.7.4 Genomics and Sexual Development ........................................................................... 294
References .......................................................................................................................................... 295
17.1 Introduction Many ascomycetes produce more than one type of spore derived mitotically or meiotically. The genus aspergilli consists of at least 186 species, and 72 species among them are known to produce ascospores as well as conidia, indicating that the genus aspergilli includes perfect fungi (Pontecorvo et al., 1953; Samson, 1994). Aspergillus nidulans is one of the genetic model organisms and is representative of the perfect Aspergillus species. The name Aspergillus came from aspergillum, which is an apparatus for sprinkling holy water, by observing the shape of the conidiophore. The species name nidulans means “nest-like,” which represents a closed fruiting body, cleistothecia. Taken together, the name Aspergillus nidulans means a fungus having asexual conidiophores and sexual cleistothecia. In addition, since it is a perfect fungus, A. nidulans has a sexual stage name, that is, teleomorph,
which is Emericella nidulans. Unlike many other heterothallic fi lamentous fungi including Neurospora crassa, which require a sexual partner having an opposite mating type, A. nidulans is homothallic, which means it does not need a different mating-type partner to produce fruiting bodies. In other words, a single conidium or ascospore of A. nidulans can complete both the asexual and sexual life cycle in normal conditions that are governed by a genetically programmed regulation system (Pontecorvo et al., 1954; Braus et al., 2002).
