Influences of Light Regimes on Reproduction, Germination, Pigmentation, Pathogenesis and Overall development of a Variety of Filamentous Fungi – A Review

Light influences important physiological and morphological responses in fungi, hence they can sense near UV, blue, green, red and far-red lights using up to eleven (11) photoreceptors and signaling cascades to control a larger proportion of the genomes and adapt to environmental factors. Though light is an environmental signal regulating myriad of biological processes, fungi do not utilize it as a source of energy for synthesis of food but for information and other developmental processes. Two genes WC-1 and WC-2 have been identified to function as photoreceptor for blue light proteins or orthologs and transcription factor for other light induced phenomenon. Additionally, conserved WCC photoreceptor orthologs (FaWC1 and FaWC2) may also perform divergent roles in some fungal species such as light signals to regulate UV resistance, secondary metabolism and sexual reproduction as well as for virulent expression. Response to white light irradiation has also elicited different morphological and physiological changes in various species of fungi such as asexual reproduction and induction or inhibition of several developmental processes. Mushrooms also requires light for developmental processes such as the asexual stage for completion of its life cycle whereas it is unnecessary at the vegetative stage. This review provides some recent crucial impact of light irradiation on the developmental processes of fungi such as sporogenesis, germination/conidiation, reproductive development, pathogenesis, mycotoxin and mushroom development even though they are generally known to be achlorophyllous and non-photosynthetic. Thus, identifying conditions of light regime that will favour fungal development with reduced mycotoxin production will be beneficial to animals and human health. Additionally, developing new techniques to control fungal species may lead to the development of faster and more effective food-processing methods.