Growth, Differentiation and Sexuality

13 Photomorphogenesis and Gravitropism in Fungi
L.M. Corrochano 1 ,P.Galland 2
CONTENTS
I. Introduction ......................... 233
II. Photomorphogenesis .................. 233
A. Ascomycota ....................... 235
1. Neurospora crassa ................. 235
a) ThePhotoreceptorSystem ....... 235
b) Effect of Light on Hyphal Growth . . 236
c) Photoconidiation .............. 237
d) Effect of Light
onSexualDevelopment ......... 238
e) Photoperiodism in Neurospora . . . 238
f) Photoreceptor Genes in Neurospora 239
2. Aspergillus nidulans ............... 239
a) Photoconidiation .............. 239
b) Effect of Light
on Sexual Development
andtheCircadianRhythm....... 240
3. Trichoderma ..................... 241
a) Photoconidiation .............. 241
4.OtherAscomycetes................ 241
B. Zygomycota ....................... 242
1. Phycomyces blakesleeanus .......... 242
a) Photophorogenesis............. 242
b) PhotophorogenesisMutants...... 242
c) LightTransductionChain........ 242
d) Effect of Light
onSexualDevelopment ......... 243
C. Basidiomycota ..................... 243
1. Coprinus cinereus (Coprinopsis cinerea) 243
a) Effect of Light
on Fruiting Body Development . . . 244
b) Other Effects
ofLightonDevelopment ........ 244
c) LightTransductionPathway...... 244
2. Cryptococcus neoformans ........... 245
III. Gravitropism ......................... 245
A. CriteriaforGravisusceptors........... 246
B. Basidiomycota ..................... 247
1.Gravisusceptors .................. 248
2. Kinetics, Dose Dependence
andThreshold ................... 248
3.Gravimorphogenesis .............. 249
C. Ascomycota ....................... 249
D. Zygomycota ....................... 249
1.Gravisusceptors .................. 249
1 Departamento de Genética, Facultad de Biología, Universidad de
Sevilla, Avenida Reina Mercedes 6, Apartado 1095, 41080 Sevilla,
Spain
2 Fachbereich Biologie, Philipps-Universität, Lahnberge, 35032
Marburg, Germany
2. Kinetics, Dose Dependence
andThreshold ................... 250
3.CytoskeletonandCalcium.......... 250
4. Sine Law and Exponential Law . . . . . . . 251
5.GravitropismMutants ............. 251
E. Glomeromycota .................... 251
IV. Conclusions .......................... 252
References ........................... 252
I. Introduction
Light and gravity are ubiquitous in nature and
serveassignalstoguidegrowthanddevelopment
of many types of organisms. Fungi take advantage
of the presence of ambient light, and changes
of light quality and quantity to modulate several
steps of their development. The induction of spore
formation and the development of structures for
spore dispersal are the most obvious fungal photoresponses
and have attracted the attention of scientists
worldwide. Many organisms sense gravity
as a guiding signal for directed growth, sometimes
in combination with other environmental signals
such as light. Fungi use the information provided
by the measurement of gravity to orient the growth
of morphological structures, many of them also involved
in spore development and dispersal. Light
and gravity are thus environmental stimuli that
are responsible independently or in coordination
for the final development and appearance of many
fungi.
II. Photomorphogenesis
Fungal development is often modified by the presence
of light (Table 13.1). The main developmental
transitions in the fungal life cycle are spore germination,
hyphal growth and branching, and formation
of reproductive structures for spore development
and dispersal. These developmental transitions
are regulated by various environmental fac-
The Mycota I
Growth, Differentation and Sexuality
Kües/Fischer (Eds.)
© Springer-Verlag Berlin Heidelberg 2006