|WEN, NUAN - Washington State University|
|MANNING-THOMPSON, YVONNE - Washington State University|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2019
Publication Date: 7/12/2019
Citation: Wen, N., Manning-Thompson, Y., Garland Campbell, K.A., Paulitz, T.C. 2019. Distribution of Cereal Cyst Nematodes (Heterodera avenae and H. filipjevi) in Eastern Washington State. Plant Disease. 103(9):2171-2178. https://doi.org/10.1094/PDIS-10-18-1881-SR.
Interpretive Summary: Cereal Cyst Nematode (CCN) (Heterodera avenae and H. filipjevi) are important pathogens of wheat and other cereal crops. H. avenae was first found in the US in W. Oregon and moved to NE Oregon in the 1980s. In 2010 we discovered it in eastern Washington, along with H. filipjevi in 2014. But little was known about the distribution of these two pathogens in wheat in eastern Washington. We developed DNA techniques that could identify the species in a single cyst, and surveyed fields from 2010 to 2017. H. avenae is the most widely distributed, while H. filipjevi appears to be confined to SE Whitman County.
Technical Abstract: Cereal cyst nematodes (CCN, Heterodera avenae and H. filipjevi), cause substantial world-wide yield loss in small grain cereals such as wheat, barley and oat. H. avenae was first detected in the United States in Oregon in 1974 and had spread to northeast Oregon by the mid-1980s. Although H. avenae was detected in eastern Washington in 1984, extensive infestations were not noticed until 2010. H. filipjevi, first detected in Oregon in 2008, was found in eastern Washington in 2014. Thus an extensive survey was undertaken in eastern Washington and methods were developed to distinguish species using DNA sequencing of single cysts. In this study, we surveyed 356 wheat and barley fields in eastern Washington from 2007 to 2017. CCN from the infested locations were identified to species level by sequencing the ribosomal internal transcribed spacers (ITS) and/or 28S ribosomal RNA (rRNA) genes. The sequences were compared in the GenBank database in the National Center for Biotechnology Information (NCBI), to identify species. The results show that H. filipjevi was primarily confined to southern Whitman County, WA; and H. avenae had a wider distribution across the higher precipitation annual cropping area of eastern Whitman County, WA. Knowledge of species identification is critical for deployment of host resistance as an effective means of management, since resistance genes for one species of CCN may not be effective against the other.