Identification and Characterization of a Red-Light Sensor FphA in Aspergillus flavus

Area of Science:

• Mycology
• Plant Pathology
• Molecular Biology

Background:

• Aspergillus flavus produces aflatoxin B1, a potent toxin contaminating food and feed.
• Environmental signals influence A. flavus, but red light's role is unknown.

Purpose of the Study:

• Identify and characterize the red-light sensing mechanism in A. flavus.
• Investigate the function of the identified red-light sensor in fungal development and toxin production.

Main Methods:

• Gene knockout and complementation of the fungal phytochrome A (FphA) gene.
• Phenotypic analysis of wild-type, knockout, and complementary strains.
• Assessment of aflatoxin B1 biosynthesis, conidia and sclerotia development, and pathogenicity.

Main Results:

• A hypothetical protein was identified as fungal phytochrome A (FphA), a red-light sensor.
• FphA regulates aflatoxin B1 biosynthesis, promoting it in the absence of the sensor.
• FphA is crucial for conidia and sclerotia development and peanut infection, with its RR domain being essential for function.

Conclusions:

• Fungal phytochrome A (FphA) is a key regulator of A. flavus development and aflatoxin B1 production in response to red light.
• FphA represents a potential target for controlling A. flavus proliferation and its associated mycotoxins.