Development of a new tool to detect Melampsora medusae f.sp. tremuloidae causing rust disease on Populus tremuloides.

Melampsora medusae f. sp. tremuloidae is a quarantine organism for the EU. In North America, this fungus causes rust disease on Populus tremuloides. In Europe, Populus tremula, an aspen closely related to P. tremuloides, is widespread and plays an important ecological role. Introduction of M. medusae f. sp. tremuloidae into Europe could be a major risk if this forma specialis could evolve and become virulent on P. tremula. To date no PCR-based assay exists to specifically detect M. medusae f. sp. tremuloidae. In this study, a sensitive and specific real-time PCR assay has been developed based on the 28S rDNA. The assay proved to be reliable using many real-time PCR kits and platforms. It can be used to monitor the introduction and the spread of M. medusae f. sp. tremuloidae in the context of phytosanitary regulations.