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Malassezia-like fungi widespread, diverse

Members of the Malassezia species are likely some of the most widespread fungi on the planet, according to a recently published literature review by Anthony S. Amend, PhD.

For more than 150 years, researchers have linked these fungi with skin conditions such as dandruff and eczema. However, the fungi is difficult to culture axenically, which has hindered the study of their systematics and diversity, according to Amend.

One of the hallmarks of Malassezia species is their incomplete fatty acids synthesis metabolic pathway, and dependence on a suite of extracellular lipases, phospholipases and acid sphingomyelinases, Amend wrote.

Despite being difficult to cultivate, putative Malassezia are readily detected in environmental DNA samples using standard fungal “barcoding” approaches.

Amend explained that M. restricta may be widespread, as DNA sequences similar to these species have been detected in habitats as diverse as deep-sea sediments, hydrothermal vents, stony corals, lobster larval guts and many other marine environments, in addition to Antarctic soils and on various plant roots.

The ribosomal DNA sequences of Malassezia in these studies are nearly identical to those of human associates, “suggesting either a very recent divergence in habitat or else that these organisms are highly tolerant to some of the planet’s most extreme environments,” Amend wrote.

Recent studies have shown that putatively familiar and novel Malassezia-like organisms live on marine hosts such as pinnipeds (often generalized as “seals”) and marine sponges from Hawaii.

Disclosure: Amend acknowledges the funding from NSF award 1255972. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.