Fungal metabolic plasticity and sexual development mediate induced resistance to arthropod fungivory.
Prey organisms do not tolerate predator attack passively but react with a multitude of inducible defensive strategies. Although inducible defence strategies are well known in plants attacked by herbivorous insects, induced resistance of fungi against fungivorous animals is largely unknown. Resistance to fungivory is thought to be mediated by chemical properties of fungal tissue, i.e. by production of toxic secondary metabolites. However, whether fungi change their secondary metabolite composition to increase resistance against arthropod fungivory is unknown. We demonstrate that grazing by a soil arthropod, Folsomia candida, on the filamentous fungus Aspergillus nidulans induces a phenotype that repels future fungivores and retards fungivore growth. Arthropod-exposed colonies produced significantly higher amounts of toxic secondary metabolites and invested more in sexual reproduction relative to unchallenged fungi. Compared with vegetative tissue and asexual conidiospores, sexual fruiting bodies turned out to be highly resistant against fungivory in facultative sexual A. nidulans. This indicates that fungivore grazing triggers co-regulated allocation of resources to sexual reproduction and chemical defence in A. nidulans. Plastic investment in facultative sex and chemical defence may have evolved as a fungal strategy to escape from predation.
Molecular Phytopathology and Mycotoxin Research, Georg-August-University Göttingen, , Göttingen, Germany, J.F. Blumenbach Institute of Zoology and Anthropology, Georg-August-University Göttingen, , Göttingen, Germany.
Katharina
K
Döll
Subhankar
S
Chatterjee
Stefan
S
Scheu
Petr
P
Karlovsky
Marko
M
Rohlfs
D000704:Analysis of Variance; D000818:Animals; D001233:Aspergillus nidulans / Q000378:metabolism* / Q000472:pathogenicity / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D048690:Fruiting Bodies, Fungal / Q000737:chemistry* / Q000502:physiology; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D007313:Insecta / Q000502:physiology*; D011235:Predatory Behavior / Q000502:physiology*; D012098:Reproduction / Q000502:physiology; D064210:Secondary Metabolism / Q000502:physiology; D013045:Species Specificity; D053719:Tandem Mass Spectrometry
chemical defence; facultative sexuality; induced resistance; insect–fungus ecology; mycotoxins