Global Molecular Diversity of the Halotolerant Fungus Hortaea werneckii.

Alessia Marchetta,Bert Gerrits Van Den Ende,Ferry Hagen,Filomena De Leo,Clara Urzì,Montarop Sudhadham,Abdullah Al-Hatmi,Nina Gunde-Cimerman,Sybren De Hoog,Polona Zalar

doi:10.3390/life8030031

Abstract

A global set of clinical and environmental strains of the halotolerant black yeast-like fungus Hortaea werneckii are analyzed by multilocus sequencing and AFLP, and physiological parameters are determined. Partial translation elongation factor 1-α proves to be suitable for typing because of the presence/absence of introns and also the presence of several SNPs. Local clonal expansion could be established by a combination of molecular methods, while the population from the Mediterranean Sea water also responds differently to combined temperature and salt stress. The species comprises molecular populations, which in part also differ physiologically allowing further diversification, but clinical strains did not deviate significantly from their environmental counterparts.

Highlights

Knowledge on fungi living under extreme conditions has increased significantly over the last two decades
Sequencing of the rDNA Internal transcribed spacer region (ITS) region and subsequent comparison in GenBank and in an in-house black yeast database maintained at the Westerdijk Institute confirmed all 67 strains belong to Hortaea werneckii, with identity ≥ 99%, e-value: 0, without gaps
The two main clusters, A and B, obtained from the Amplified Fragment Length Polymorphism (AFLP) analysis matched, with some exceptions, with the two clusters observed in the Haplotype network of translation elongation factor-1α (TEF1) (Figure 2)

Summary

Introduction

Knowledge on fungi living under extreme conditions has increased significantly over the last two decades. The halophilic black yeast H. werneckii is one of the most salt tolerant eukaryotic organisms so far described [8] It is characterized by melanin production, pleomorphism of yeast and filamentous phases, and meristematic development [9,10]—characters we observe in numerous rock-inhabiting fungi [6]. In culture it reproduces clonally, a sexual state is not known. The fungus has a global distribution in seawater and adjacent habitats, such as sea sponges, marine and salted freshwater fish, corals, microbial mats in salterns, beach soil, salt marsh plants and salted food [11,12,13]. The fungus is consistently encountered in deep Mediterranean Seawater [14]

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Results

Conclusion