Evaluation\xa0of PCR markers for Phytophthora infestans mating type determination

Marta Brylińska,Sylwester Sobkowiak,Jadwiga Śliwka,Emil Stefańczyk

doi:10.1007/s10658-018-1445-4

Marta Brylińska, Sylwester Sobkowiak + Show 2 more

https://doi.org/10.1007/s10658-018-1445-4

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Abstract

Late blight is a devastating potato disease caused by Phytophthora infestans. This organism can reproduce asexually and sexually between the strains of two mating types named A1 and A2. Mating type is an important strain characteristic affecting the pathogen’s population structure. We validate different PCR markers for P. infestans mating type determination by comparison of the results obtained with the markers (W16, S1, PHYB) with the pairing test results for 26 isolates collected worldwide and for a group of 146 Polish isolates. This study identifies an interesting feature of the isolates of genotype US-1. For all these A1 mating type isolates, the product specific for A2 isolates is amplified using the marker W16. Analysis of sequences of W16 PCR products indicates high similarity of the US-1 isolates with modern A2 mating type isolates. When US-1 isolates are excluded from analysis, 95 and 96% of isolates are correctly assigned by markers W16 and S1, respectively, when compared with the pairing test results. Marker PHYB produces 14% of discrepant results with the pairing test. Our results show that molecular markers can be useful tools for P. infestans mating type determination, but their application should be preceded by validation in each local population since their efficiency may vary depending on a pathogen’s genotype.

Highlights

Phytophthora infestans (Mont.) de Bary, a member of the Oomycota, is one of the most important destroyers of potato (Solanum tuberosum) and tomato (S. lycopersicum) worldwide
Pairing tests confirmed the results obtained by other laboratories for the 26 control P. infestans isolates (Table 1)
Among 146 Polish P. infestans isolates from the year 2011, 94 isolates were A1 mating type and 52 isolates were A2 mating type according to the pairing test

Summary

Introduction

Phytophthora infestans (Mont.) de Bary, a member of the Oomycota, is one of the most important destroyers of potato (Solanum tuberosum) and tomato (S. lycopersicum) worldwide. This pathogen causes a disease named late blight and is able to completely devastate plants within a week. The average costs of yield losses and chemical protection against late blight are high and calculated at over 6 billion USD worldwide (Haverkort et al 2008). P. infestans is a hemibiotrophic organism, which can reproduce asexually (forming sporangia). Sporangia are dispersed by the wind for long distances and that causes a rapid spread of the disease (Govers et al 1997). The heterothallic nature of P. infestans was discovered by Smoot et al (1958) and Gallegly and Galindo (1958)

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