Melanin and pyomelanin in Aspergillus fumigatus: from its genetics to host interaction

  1. U. Perez Cuesta 1
  2. L. Aparicio Fernandez 1
  3. Xabier Guruceaga 1
  4. Leire Martin Souto 1
  5. A. Abad Diaz de Cerio 1
  6. Aitziber Antoran 1
  7. I. Buldain 1
  8. Fernando L. Hernando 1
  9. Andoni Ramírez Garcia 1
  10. Aitor Rementería Ruiz 1
  1. 1 University of the Basque Country (UPV/EHU)
International microbiology: official journal of the Spanish Society for Microbiology

ISSN: 1618-1905

Year of publication: 2020

Volume: 23

Issue: 1

Pages: 55-63

Type: Article

More publications in: International microbiology: official journal of the Spanish Society for Microbiology


Aspergillus fumigatus is a worldwide-distributed saprophytic fungus and the major cause of invasive aspergillosis. This fungus can produce two types of melanin—dihydroxynaphthalene melanin (DHN-melanin) and pyomelanin. These pigments are considered important resistance mechanisms to stress, as well as virulence factors. The aim of this review is to present the current knowledge of the genetic basis and metabolic pathways of melanin production, their activation, function, and interaction with the host immune system. The DHN-melanin pathway is encoded in a cluster that includes six genes (abr1, abr2, ayg1, arp1, arp2, and pksP/alb1 genes) whose encoded proteins seem to be the origin of the pigment in endosomes. These vesicles are secreted and the pigment is subsequently located in the wall of the conidium beneath the rodlet layer. Unlike DHN-melanin, pyomelanin does not have its own biosynthetic pathway but is related to the activation of the L-tyrosine/L-phenylalanine degradation pathway that includes a cluster of six genes (hppD, hmgX, hmgA, fahA, maiA, and hmgR). Its production is due to the polymerization of homogentisic acid and is linked to conidial germination. Despite the knowledge gained in recent years, further studies will be necessary to confirm the pathways that produce these pigments and their role in the virulence mechanisms of A. fumigatus.