Specific detection of the wheat blast pathogen (Magnaporthe oryzae Triticum) by loop-mediated isothermal amplification

Jarred Yasuhara-Bell, Kerry F. Pedley, Mark Farman, Barbara Valent, James P. Stack

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Wheat blast, caused by the Magnaporthe oryzae Triticum pathotype, is an economically important fungal disease of wheat. Wheat blast symptoms are similar to Fusarium head scab and can cause confusion in the field. Currently, no in-field diagnostic exists for M. oryzae Triticum. Loop-mediated isothermal amplification (LAMP) primers were designed to target the PoT2 and MoT3 loci, previously shown to be specific for M. oryzae and M. oryzae Triticum, respectively. Specificity was determined using 158 M. oryzae strains collected from infected wheat and other grasses and representing geographic and temporal variation. Negative controls included 50 Fusarium spp. isolates. Sensitivity was assessed using 10-fold serial dilutions of M. oryzae Triticum gDNA. PoT2- and MoT3-based assays showed high specificity for M. oryzae and M. oryzae Triticum, respectively, and sensitivity to approximately 5 pg of DNA per reaction. PoT2 and MoT3 assays were tested on M. oryzae Triticuminfected wheat seed and spikes and identified M. oryzae and M. oryzae Triticum, respectively, using a field DNA extraction kit and the portable Genie II system. The mitochondrial NADH-dehydrogenase (nad5) gene, an internal control for plant DNA, was multiplexed with PoT2 and MoT3 and showed results comparable with individual assays. These results show applicability for M. oryzae Triticum field surveillance, as well as identifying nonwheat species that may serve as a reservoir or source of inoculum for nearby wheat fields.

Original languageEnglish
Pages (from-to)2550-2559
Number of pages10
JournalPlant Disease
Volume102
Issue number12
DOIs
StatePublished - Dec 2018

Bibliographical note

Funding Information:
Funding: This work was supported by the Agriculture and Food Research Initiative (2009-55605-05201) and the United States Department of Agriculture National Institute of Food and Agriculture (2013-68004-20378).

Publisher Copyright:
© 2018 The American Phytopathological Society.

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science

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