A recently discovered mechanism can play a critical role in virulence of an infectious fungus, as per Howard Hughes Medical Institute investigators at Duke University Medical Center.

The finding suggested that changes in light after fungal invasion of the human body can be termed as a important but previously neglected cue that sparks infection.

From Sciencedaily.com:

The potentially life-threatening fungus C. neoformans invades the central nervous system to cause disease, most commonly in patients who lack a functioning immune system, such as organ transplant recipients, those with HIV/AIDS, and patients treated with steroids or cancer chemotherapy. The fungus’ global importance as a health threat has therefore risen in parallel with the increase in immunosuppressive therapies and the worldwide HIV/AIDS epidemic.

Light normally inhibits mating of C. neoformans. The Duke team has now identified two genes responsible for that light response. Loss of the same genes also reduces fungal virulence in mice, they reported.

Earlier studies had linked the genes to light-sensing in another distantly related fungal lineage, an indication that the fungal light sensor arose early in evolution and may be shared by many extant fungal species. Other well-studied fungi, such as Saccharomyces cerevisiae, or baker’s yeast, have apparently lost their ability to sense light, Heitman said, and have neither of the conserved light-sensing proteins.

“Fungi have many negative implications for human life as they lead to human disease, as well as plant disease and mold,” said Idnurm, a post-doctoral fellow at Duke. “However, fungi also play important beneficial roles, for example, as a source of food and pharmaceuticals.

HHMI investigator Joseph Heitman, M.D., James B. Duke professor of molecular genetics and microbiology and medicine at Duke, remarked that the light therapy could provide an effective way to combat against many fungal infections when used in a combination with anti-fungal treatments.