# Moesziomyces antarcticus MMF1 Has a Role in the Secretion of Mannosylerythritol Lipids

## TL;DR

This study shows that the MMF1 gene in Moesziomyces antarcticus is important for secreting MELs, a type of glycolipid, but not for their production or cell growth.

## Contribution

The study demonstrates the role of MMF1 in MEL secretion in M. antarcticus, revealing a novel glycolipid secreted when MMF1 is disrupted.

## Key findings

- Disruption of MMF1 in M. antarcticus reduced secretion of MEL-A, MEL-B, and MEL-C.
- A distinct glycolipid was secreted by the MMF1 mutant strain.
- MMF1 is not essential for MEL synthesis or cell growth in M. antarcticus.

## Abstract

Mannosyl erythritol lipids (MELs) are glycolipid biosurfactants produced by Ustilaginomycete yeasts. The MEL biosynthetic pathway has been characterized in Ustilago maydis where a putative transporter encoded by MMF1 is required for the secretion of the glycolipid surfactant to the extracellular space. The anamorphic yeast Moesziomyces antarcticus is a prolific producer of MELs, but the mechanism of MEL secretion is less well characterized than in U. maydis. Homologous recombination was employed to generate a disruption of the MMF1 gene in M. antarcticus JCM10317. This mutation did not prevent the intracellular accumulation of MEL species but did result in significantly reduced secretion of the conventional MEL-A, MEL-B and MEL-C species detectable by thin-layer chromatography. However, the mutant strain did secrete a glycolipid species that is distinct from conventional MEL-A/B/C and similar to a glycolipid secreted by MMF1 mutant strains of U. maydis and Pseudozyma tsukubaensis. Despite the defect in MEL secretion displayed by the M. antarcticus strain harbouring a disrupted MMF1 gene, these cells did not display a significant defect in growth or cell morphology. The findings of this investigation provide evidence that M. antarcticus MMF1 encodes a transporter required for the secretion of MELs but not required for MEL synthesis or cell growth.