Abstract Detail

Karling Lecture

Corrochano, Luis M. [1].

Perception in fungi: sensing light and other signals.

Fungi use signals from the environment to regulate growth, development, and metabolism. For example, the growth of the fruiting bodies, sporangiophores, of Phycomyces blakesleeanus is governed by several environmental signals, including light, gravity, touch, wind, and the presence of nearby objects. These signals allow sporangiophore growth towards open air for efficient spore dispersal. The perception of light in fungal biology has been investigated in most detail. Light can be used as a signal from the environment to increase reproductive success, but it can be harmful due to damage to DNA. Fungi use light as a signal to regulate development, modulate growth, and promote the synthesis of protective pigments, like carotenoids. Fungal photoreceptors sense blue and red light and, after light reception, activate the transcription of genes that lead to the accumulation of the proteins needed for the cellular responses to light. The damage to DNA caused by UV radiation is corrected by blue-light sensing photolyases. Most fungi use proteins similar to WC-1 and WC-2 from Neurospora crassa for sensing blue light. In N. crassa and other fungi these two proteins form a photoreceptor and transcription factor complex that binds to the promoters of light-regulated genes to activate transcription. The activation by light of genes for enzymes that participate in pigment biosynthesis leads to the activation of metabolic pathways that should help to protect the cell from excessive light. This may be relevant in nature, as we have observed that the capacity of wild-type strains of Neurospora to accumulate carotenoids after exposure to light correlates with the latitude of the site where the strains were collected. Mucoromycotina fungi have multiple wc genes. In Phycomyces two of them encode a photoreceptor complex composed of MadA and MadB, that is required for all responses to light. A comparison of the set of photoreceptor genes in the genomes of selected fungi gives clues on the origin of fungal vision and its evolution across the fungal kingdom. The presence of multiple wc-1 genes have been observed in Mucoromycotina fungi, but other fungal genomes have a very complete set of additional photoreceptor genes that should allow light reception in a wide range of wavelengths, from the near UV to red light. Different evolutionary strategies have helped fungi to acquire the proteins that allow the perception of light.

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1 - University of Seville, Department of Genetics, Avda. Reina Mercedes, Sevilla, 41012, Spain

Keywords:
Phycomyces blakesleeanus
Neurospora crassa
Photobiology
phototropism
Photoreceptor
Blue light.

Presentation Type: Special Presentation
Session: S03
Location: Salon 8/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 9:15 AM
Number: S03001
Abstract ID:879
Candidate for Awards:None