Characterization of Blue Light Receptors in Aspergillus flavus

Aspergillus flavus is one of the potent pathogenic fungi that produce carcinogenic secondary metabolites, commonly known as aflatoxins. A. flavus mainly spread through airborne asexual spores, which are produced by asexual development under the influence of environmental factors such as light, temperature, and aeration. Light is a general environmental factor that regulates asexual development, stress resistance, and even mycotoxins in several fungi. When light is served as an external signal, photoreceptor proteins sense through a chromophore. Previous studies showed that FphA is a phytochrome for red-light detection, and LreA and LreB are white-collar homologs for blue-light detection in Aspergillus nidulans. It was proved that they are essential for asexual development in A. nidulans. However, it has not yet been studied in A. flavus. Therefore, we have studied the roles of light sensors in A. flavus. First, we produced each deletion mutant and analyzed asexual development. In results, the number of asexual spores was decreased in the deletion of lreA and lreB, while there was not affected in the ΔfphA mutant. Next, we checked the aflatoxin production in each deletion strain. As a result, light sensors were found to affect the production of aflatoxins. Taken together, these results suggest that three photosensors are present in A. flavus and regulate asexual development and aflatoxin production. *Supported by the Ministry of Environment