Abstract Detail

Mycological Section

Sivagnanam, Kumaran [1], Barasubiye, Tharcisse [2], Seifert, Keith A. [2], Perreault, Hélène [3], Graefenhan, Tom [1].

MALDI-TOF-MS identification and characterization of Alternaria species associated with cereal grains.

A variety of fungal microorganisms such as Alternaria are known to infect plants, causing foliar and seed diseases that give rise to extensive loss of yield or crop quality. In addition to causing damage to cereal grains and other plants, they have shown adverse effects toward human health due to their propensity to form mycotoxins and airborne allergens. These increasing threats justify the need to develop a powerful, rapid screening method to better characterize fungal microorganisms based on their protein and metabolite profile. This study aimed at developing a more comprehensive MALDI-TOF-MS spectral library for Alternaria species associated with Canadian grains. Mycelia of 5-day old cultures were used for extraction of proteins directly spotted onto target plates. An alpha-cyano-4-hydroxycinnamic acid (CHCA) matrix solution was applied for mass spectrometry analysis, which was performed on an Ultraflex MALDI-TOF/TOF system. Spectra were collected in the positive ion mode as an average of 240 laser shots within a mass range of 2000 Da to 20,000 Da. A total of 79 Alternaria cultures were isolated from Canadian grains and analyzed using a MADI-TOF-MS system. Acquired spectra were loaded into the MALDI Biotyper 3.1 software and preprocessed using standard algorithms for baseline subtraction, smoothing, and normalization. The generated main spectra were subjected to cluster analysis using correlation as the distance index. A comprehensive spectral library of Alternaria isolates was created based on their main spectra constructed. Furthermore, all the main spectra of Alternaria were categorized into four clusters using a clustering approach that was based on the similarity scores implemented in the software. These findings were compared with results from the phylogenetic analysis of our Alternaria isolates in order to achieve an in depth molecular level understanding of fungal populations. We conclude, MALDI-TOF-MS technology can be a valuable tool for fungal taxonomy and the rapid identification of Alternaria isolates.

1 - Canadian Grain Commission, Grain Research Laboratory, 303 Main Street, Winnipeg, MB, R3C 3G8, Canada
2 - Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, ON, K1A 0C6, Canada
3 - University of Manitoba, Chemistry Department, 517 Parker Building, Winnipeg, MB, R3T 2N2, Canada

Keywords:
Mass Spectrometry
taxonomy
polyphasic taxonomy
Pleosporales.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PMY027
Abstract ID:1352
Candidate for Awards:None