# On site discrimination between two closely related commercial strains of oyster mushroom using a loop-mediated isothermal amplification (LAMP) test

## TL;DR

This paper introduces a fast and specific LAMP test to distinguish two commercial oyster mushroom strains, SPOPPO and ALLERPO, on-site to protect intellectual property rights.

## Contribution

The first LAMP-based method to discriminate between closely related Pleurotus ostreatus strains.

## Key findings

- A LAMP test was developed to identify SPOPPO and ALLERPO within 30 minutes with high specificity.
- Strain-specific recombinations in the genome were targeted to differentiate SPOPPO and ALLERPO from other strains.
- The msh4 gene was used to distinguish sporeless strains from sporulating ones using LAMP.

## Abstract

Protection of the intellectual property (IP) rights on new crop varieties is important as it allows the breeding company or entity that produced the variety to earn back (part of) the investment. Infringement on the IP rights of mushroom varieties is not uncommon. In order to combat infringement of the IP rights on two strains of Oyster mushroom (SPOPPO and ALLERPO) it is important to be able to readily recognize and discriminate the two strains in commercial practice. This article describes the development of tools for the on-site identification of two closely related sporeless strains of Oyster mushroom.

To develop a reliable method of discriminating between SPOPPO and ALLERPO, we used either the LAMP technique or a modification of that technique. It allows for fast (within 30 min) identification of the commercially used strains SPOPPO and ALLERPO with high specificity. Fast on-site answers on strain identity can be important when experiencing unexpected strain behavior or when strains are of suspect origin. Both strains are discriminated from sporulating strains by a LAMP reaction on the intact version of the msh4 gene; sporeless strains contain a msh4 gene with a large insert that renders the associated protein inactive.

SPOPPO and ALLERPO are distinguished from each other and other commercially used Pleurotus ostreatus strains by LAMP reactions that target genomic regions with strain specific recombinations. To our knowledge, this is the first time LAMP reactions have been developed to discriminate between Pleurotus ostreatus strains.

The online version contains supplementary material available at 10.1007/s11033-025-11156-0.