MALDI-TOF MS as a method for rapid identification of Phytophthora de Bary, 1876

PeerJ. 2021 Jul 19:9:e11662. doi: 10.7717/peerj.11662. eCollection 2021.

Abstract

The number of described species of the oomycete genus Phytophthora is growing rapidly, highlighting the need for low-cost, rapid tools for species identification. Here, a collection of 24 Phytophthora species (42 samples) from natural as well as anthropogenic habitats were genetically identified using the internal transcribed spacer (ITS) and cytochrome c oxidase subunit I (COI) regions. Because genetic identification is time consuming, we have created a complementary method based on by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Both methods were compared and hypothesis that the MALDI-TOF MS method can be a fast and reliable method for the identification of oomycetes was confirmed. Over 3500 mass spectra were acquired, manually reviewed for quality control, and consolidated into a single reference library using the Bruker MALDI Biotyper platform. Finally, a database containing 144 main spectra (MSPs) was created and published in repository. The method presented in this study will facilitate the use of MALDI-TOF MS as a complement to existing approaches for fast, reliable identification of Phytophthora isolates.

Keywords: Biotyping; COI; Database; ITS; Library; Maldi; Mass spectra; Phytophthora; Protein; Species determination.

Grants and funding

This work was supported by the internal grant agency of Czech University of Life Sciences Prague (CIGA) Project no. 20182019 and the European Regional Development Fund-Project Centre for the investigation of synthesis and transformation of nutritional substances in the food chain in interaction with potentially harmful substances of anthropogenic origin: comprehensive assessment of soil contamination risks for the quality of agricultural products (No. CZ.02.1.01/0.0/0.0/16_019/0000845). The authors received support and assistance from the Research Infrastructure METROFOOD-CZ supported by the Ministry of Education, Youth and Sports of the Czech Republic under Project No. LM2018100 and the Ministry of the Environment of the Czech Republic under Project No. IP–00027073–VUKOZ. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.