Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/1999
Publication Date: N/A
Citation: Interpretive Summary: Phytoplasmas are bacteria-like organisms that infect many plants and often cause serious crop losses. Hazelnut trees also can be infected with phytoplasmas, causing nut crop losses as well as plant death. It has been only recently that research has focused on identifying and characterizing phytoplasmas from commercial hazelnut and associating their presence with disease symptoms. In the course of this work, we have identified clover yellow edge phytoplasma as a possible component of the hazelnut stunt syndrome in Oregon. This is the first report of the occurrence of clover yellow edge phytoplasma in hazelnut and the first report of any pathogen associated with the hazelnut stunt syndrome. This information will be of use to scientists and extension personnel who are concerned with this serious disease of hazelnut in Oregon.
Technical Abstract: During investigations into the cause of a stunt syndrome affecting cultivated hazelnut trees in Oregon, clover yellow edge (CYE) phytoplasma was detected for the first time in this crop. Hazelnut stunt syndrome has been observed only in Oregon. In 1999, leaf samples were collected from two affected and two symptomless hazelnut trees in a field plot at Oregon State University, Corvallis, and from a healthy greenhouse tree that had undergone heat treatment to eliminate apple mosaic virus. Leaf samples were sent to the Beltsville laboratory where they were assessed for phytoplasma infection by use of nested polymerase chain reactions primed by phytoplasma universal primer pairs P1/P7 and F2n/R2 for amplification of phytoplasma 16S ribosomal sequences. Phytoplasma characteristic 1.2 kbp DNA sequences were amplified from all field-tree samples. No DNA sequences were amplified from samples of the heat-treated tree. Restriction fragment length polymorphism patterns of rDNA digested with endonucleases indicated that all diseased hazelnut trees and symptomless field trees were infected by clover yellow edge phytoplasma. No phytoplasmas were detected in samples from the heat-treated greenhouse tree. The presence of CYE phytoplasma in the Oregon samples is the first report of this phytoplasma infecting Corylus.