Application of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry for the Rapid Identification of Yeast Species From Polar Regions.

Chenyang He,Tao Zhang,Jianju Feng,Jing Su,Liyan Yu

doi:10.3389/fmicb.2022.832893

Abstract

Protein profiling based on matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) has proved to be a powerful tool for yeast identification. However, it is rarely used in the identification of yeast isolates from polar regions, which may be due to the limited data available for the differentiation of polar yeast species. The present study constructed a supplementary database of MALDI-TOF MS, including 33 yeast species from the Arctic and Antarctica. These yeast species were used to assess the accuracy and practicality of MALDI-TOF MS-based identification compared to the ribosomal DNA [internal transcribed spacer (ITS) and large subunit (LSU) gene regions] sequencing identification. Their dendrogram based on main spectra profiles (MSPs) in the supplementary database was somewhat consistent with their phylogenetic tree. The accuracy of MALDI-TOF MS identification was also compared by the ethanol-formic acid extraction method and the on-plate extraction method. In addition, peptide markers of some yeast species (e.g., Glaciozyma, Phenoliferia, Mrakia, and Vishniacozyma) were identified. It is concluded that the MALDI-TOF MS method can differentiate some closely related yeast species from polar regions, thus is suitable for the identification of polar yeasts.

Highlights

The Arctic and Antarctica have always been the hotspot areas to study the diversity of coldadapted microorganisms, including yeasts
22 yeast species were isolated from the Ny-Alesund Region (78°55′N, 11°56′E) located in the Svalbard Islands, and 11 species were isolated from the King George Island (62°23′S, 58°27′W) located in the South Shetland Islands
A total of 33 yeast species were isolated from the Arctic (22 species) and Antarctic (11 species) and were used for sequence similarity analysis (Table 1) and phylogenetic analysis (Figure 1)

Summary

Introduction

The Arctic and Antarctica have always been the hotspot areas to study the diversity of coldadapted microorganisms, including yeasts (i.e., a versatile group of eukaryotic organisms; Buzzini et al, 2017). It was found that polar yeasts with unique phenotypic characteristics had great biotechnological potentials, such as the production of cold-active enzymes. Multigene phylogenetic analyses based on DNA sequencing were used to identify novel yeast species isolated from various environments (Liu et al, 2015; Wang et al, 2015; Li et al, 2020). MALDI-TOF MS was effective for identifying yeast isolated from food (e.g., Candida and Debaryomyces species; Pavlovic et al, 2014), beverages (e.g., Saccharomyces species; Usbeck et al, 2014; Zhang et al, 2020), and clinical samples (e.g., Candida and Cryptococcus species; Tan et al, 2012; Patel, 2019; Pote et al, 2020)

Methods

Results

Conclusion