Diagnostic Molecular Markers for Identification of Different Races and a Pathotype of Columbia Root Knot Nematode

Abstract

Columbia root-knot nematode, Meloidogyne chitwoodi, parasitizes potato plants and causes visible small brown dots in the tuber flesh that dramatically reduce the market value of the crop. In the Pacific Northwest (PNW), two races of M. chitwoodi, Race 1 and Race 2 and a pathotype Race 1Roza exist. The races and pathotype of M. chitwoodi are primarily differentiated based on host tests. Currently, M. chitwoodi can be differentiated from M. hapla or other Meloidogyne Sp. based on morphology and by molecular markers however, the different pathotypes of M. chitwoodi cannot be differentiated using the aforementioned techniques. Based on the in silico genome comparison of M. chitwoodi Race 1, Race 2 and Race 1Roza, we developed diagnostic molecular markers that could successfully differentiate between M. chitwoodi races and pathotype. Further, we also developed three race-specific markers that can specifically amplify Race 1, Race 2, or Race 1Roza. Overall, we have potential markers that can successfully differentiate all the two races and one pathotype of M. chitwoodi through simplex PCR, which has potential application in plant disease diagnostics.