Development of loop mediated isothermal amplification for rapid species detection of Armillaria ostoyae using assimilating probe

Abstract

We introduced here the first loop mediated isothermal amplification (LAMP) assay for the identification of honey fungus, Armillaria ostoyae, a basidiomycote playing an important role in spruce declines in the Palaearctic region. In total, 101 isolates, representing three Armillaria species, were used to develop a new LAMP assay to determine species specific identification. We have here described LAMP primers enhanced with fluorescent dye that are able to amplify A. ostoyae DNA and detect fungi in a fast single step reaction. The detection limit of LAMP was 1 pg of genomic DNA per reaction. We optimized a new LAMP assay for the rapid detection of A. ostoyae using the translation elongation factor 1-α (tef1) marker and fluorescence labelled oligonucleotide assimilating probe. The LAMP assay does not require any specialized equipment, hence it can be used in the field for the rapid detection of A. ostoyae even using the portable and mobile device. The specificity of the assay was confirmed by the use of A. ostoyae strains and Armillaria cepistipes and Armillaria gallica strains, respectively. In conclusion, the assay could be a rapid, specific, sensitive and low-cost tool for identification of A. ostoyae as well as the first step for expansion of this method in practical applications.